[api] Outline the fixed32 writers on ARM cores without unaligned access too

Cortex-M0+ and ARM9 turn the four byte unaligned store into a memcpy call with a stack
temporary at every fixed32 field, and the outlined helper itself became a memcpy call
there, so the helper now spells out the byte stores. Xtensa and host objects are byte for
byte unchanged; on the RP2040 bench config the api object loses 28 bytes and the fixed32
memcpy calls.

esphome/components/api/proto.h

@@ -287,19 +287,31 @@ class ProtoWriteBuffer {
   uint8_t *pos_;
 };
 
+// A four byte unaligned store is a memcpy call on ESP-IDF (-fno-builtin-memcpy) and on ARM cores without
+// unaligned access (Cortex-M0+, ARM9), so those targets share one outlined byte store helper per fixed32
+// field. Elsewhere the write inlines to a single store, or on ESP8266 to a few stores that measured
+// faster than a call, so it stays inline.
+#if defined(USE_ESP32) || (defined(__arm__) && !defined(__ARM_FEATURE_UNALIGNED))
+#define PROTO_OUTLINE_FOR_SIZE __attribute__((noinline))
+#define PROTO_FIXED32_BYTE_STORES true
+#else
+#define PROTO_OUTLINE_FOR_SIZE inline
+#define PROTO_FIXED32_BYTE_STORES false
+#endif
+
 // Varint encoding thresholds — used by both proto_encode_* free functions and ProtoSize.
 constexpr uint32_t VARINT_MAX_1_BYTE = 1 << 7;   // 128
 constexpr uint32_t VARINT_MAX_2_BYTE = 1 << 14;  // 16384
 
-/// Static encode helpers for generated encode() functions.
-/// Generated code hoists buffer.pos_ into a local uint8_t *__restrict__ pos,
-/// then calls these methods which take pos by reference. No struct, no overhead.
-/// For sub-messages, pos is synced back to buffer before the call and reloaded after.
+/// Static encode helpers for the generated encode bodies. Each takes the write cursor by value and
+/// returns it advanced, so outlined calls at -Os chain through the return register instead of a
+/// stack slot. Helpers without a _force suffix skip fields holding the proto3 default.
 class ProtoEncode {
  public:
   /// Write a multi-byte varint directly through a pos pointer.
   template<typename T>
-  static inline void encode_varint_raw_loop(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, T value) {
+  [[nodiscard]] static inline uint8_t *encode_varint_raw_loop(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                              T value) {
     do {
       PROTO_ENCODE_CHECK_BOUNDS(pos, 1);
       *pos++ = static_cast<uint8_t>(value | 0x80);
@@ -307,48 +319,49 @@ class ProtoEncode {
     } while (value > 0x7F);
     PROTO_ENCODE_CHECK_BOUNDS(pos, 1);
     *pos++ = static_cast<uint8_t>(value);
+    return pos;
   }
-  static inline void ESPHOME_ALWAYS_INLINE encode_varint_raw(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM,
-                                                             uint32_t value) {
+  [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
+  encode_varint_raw(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint32_t value) {
     if (value < VARINT_MAX_1_BYTE) [[likely]] {
       PROTO_ENCODE_CHECK_BOUNDS(pos, 1);
       *pos++ = static_cast<uint8_t>(value);
-      return;
+      return pos;
     }
-    encode_varint_raw_loop(pos PROTO_ENCODE_DEBUG_ARG, value);
+    return encode_varint_raw_loop(pos PROTO_ENCODE_DEBUG_ARG, value);
   }
   /// Encode a varint that is expected to be 1-2 bytes (e.g. zigzag RSSI, small lengths).
-  static inline void ESPHOME_ALWAYS_INLINE encode_varint_raw_short(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM,
-                                                                   uint32_t value) {
+  [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
+  encode_varint_raw_short(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint32_t value) {
     if (value < VARINT_MAX_1_BYTE) [[likely]] {
       PROTO_ENCODE_CHECK_BOUNDS(pos, 1);
       *pos++ = static_cast<uint8_t>(value);
-      return;
+      return pos;
     }
     if (value < VARINT_MAX_2_BYTE) [[likely]] {
       PROTO_ENCODE_CHECK_BOUNDS(pos, 2);
       *pos++ = static_cast<uint8_t>(value | 0x80);
       *pos++ = static_cast<uint8_t>(value >> 7);
-      return;
+      return pos;
     }
-    encode_varint_raw_loop(pos PROTO_ENCODE_DEBUG_ARG, value);
+    return encode_varint_raw_loop(pos PROTO_ENCODE_DEBUG_ARG, value);
   }
-  static inline void ESPHOME_ALWAYS_INLINE encode_varint_raw_64(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM,
-                                                                uint64_t value) {
+  [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
+  encode_varint_raw_64(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint64_t value) {
     if (value < VARINT_MAX_1_BYTE) [[likely]] {
       PROTO_ENCODE_CHECK_BOUNDS(pos, 1);
       *pos++ = static_cast<uint8_t>(value);
-      return;
+      return pos;
     }
-    encode_varint_raw_loop(pos PROTO_ENCODE_DEBUG_ARG, value);
+    return encode_varint_raw_loop(pos PROTO_ENCODE_DEBUG_ARG, value);
   }
   /// Encode a 48-bit MAC address (stored in a uint64) as varint.
   /// Real MAC addresses occupy the full 48 bits (OUI in upper 24), so the
   /// fast path -- any non-zero bit in the top 6 of 48 -- emits exactly 7 bytes
   /// with no per-byte branch. Falls back to the general loop otherwise.
   /// Caller must guarantee value fits in 48 bits (checked in debug builds).
-  static inline void ESPHOME_ALWAYS_INLINE encode_varint_raw_48bit(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM,
-                                                                   uint64_t value) {
+  [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
+  encode_varint_raw_48bit(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint64_t value) {
 #ifdef ESPHOME_DEBUG_API
     assert(value < (1ULL << (MAC_ADDRESS_SIZE * 8)) && "encode_varint_raw_48bit: value exceeds 48 bits");
 #endif
@@ -363,38 +376,39 @@ class ProtoEncode {
       pos[4] = static_cast<uint8_t>((value >> 28) | 0x80);
       pos[5] = static_cast<uint8_t>((value >> 35) | 0x80);
       pos[6] = static_cast<uint8_t>(value >> 42);
-      pos += 7;
-      return;
+      return pos + 7;
     }
-    encode_varint_raw_64(pos PROTO_ENCODE_DEBUG_ARG, value);
+    return encode_varint_raw_64(pos PROTO_ENCODE_DEBUG_ARG, value);
   }
-  static inline void ESPHOME_ALWAYS_INLINE encode_field_raw(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM,
-                                                            uint32_t field_id, uint32_t type) {
-    encode_varint_raw(pos PROTO_ENCODE_DEBUG_ARG, (field_id << 3) | type);
+  [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
+  encode_field_raw(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, uint32_t type) {
+    return encode_varint_raw(pos PROTO_ENCODE_DEBUG_ARG, (field_id << 3) | type);
   }
   /// Write a single precomputed tag byte. Tag must be < 128.
-  static inline void ESPHOME_ALWAYS_INLINE write_raw_byte(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM,
-                                                          uint8_t b) {
+  [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
+  write_raw_byte(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint8_t b) {
     PROTO_ENCODE_CHECK_BOUNDS(pos, 1);
     *pos++ = b;
+    return pos;
   }
   /// Reserve one byte for later backpatch (e.g., sub-message length).
   /// Advances pos past the reserved byte without writing a value.
-  static inline void ESPHOME_ALWAYS_INLINE reserve_byte(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM) {
+  [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
+  reserve_byte(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM) {
     PROTO_ENCODE_CHECK_BOUNDS(pos, 1);
-    pos++;
+    return pos + 1;
   }
   /// Write raw bytes to the buffer (no tag, no length prefix).
-  static inline void ESPHOME_ALWAYS_INLINE encode_raw(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM,
-                                                      const void *data, size_t len) {
+  [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
+  encode_raw(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, const void *data, size_t len) {
     PROTO_ENCODE_CHECK_BOUNDS(pos, len);
     std::memcpy(pos, data, len);
-    pos += len;
+    return pos + len;
   }
   /// Encode tag + 1-byte length + raw string data. For strings with max_data_length < 128.
   /// Tag must be a single-byte varint (< 128). Always encodes (no zero check).
-  static inline void encode_short_string_force(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint8_t tag,
-                                               const StringRef &ref) {
+  [[nodiscard]] static inline uint8_t *encode_short_string_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                                 uint8_t tag, const StringRef &ref) {
 #ifdef ESPHOME_DEBUG_API
     assert(ref.size() < 128 && "encode_short_string_force: string exceeds max_data_length < 128");
 #endif
@@ -402,137 +416,187 @@ class ProtoEncode {
     pos[0] = tag;
     pos[1] = static_cast<uint8_t>(ref.size());
     std::memcpy(pos + 2, ref.c_str(), ref.size());
-    pos += 2 + ref.size();
+    return pos + 2 + ref.size();
   }
-  /// Write a precomputed tag byte + 32-bit value in one operation.
-  static inline void ESPHOME_ALWAYS_INLINE write_tag_and_fixed32(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM,
-                                                                 uint8_t tag, uint32_t value) {
+  /// Unaligned little-endian store; __builtin_memcpy stays inline even under -fno-builtin-memcpy.
+  static inline void ESPHOME_ALWAYS_INLINE write_fixed32_le(uint8_t *__restrict__ pos, uint32_t value) {
+    if constexpr (PROTO_FIXED32_BYTE_STORES) {
+      // Spelled out so the outlined helper does not itself become a memcpy call
+      pos[0] = static_cast<uint8_t>(value);
+      pos[1] = static_cast<uint8_t>(value >> 8);
+      pos[2] = static_cast<uint8_t>(value >> 16);
+      pos[3] = static_cast<uint8_t>(value >> 24);
+    } else {
+      const uint32_t le = convert_little_endian(value);
+      __builtin_memcpy(pos, &le, 4);
+    }
+  }
+  /// Write a precomputed tag byte + 32-bit value. Outlined on embedded: one copy beats inline stores per field.
+  [[nodiscard]] static PROTO_OUTLINE_FOR_SIZE uint8_t *write_tag_and_fixed32(
+      uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint8_t tag, uint32_t value) {
     PROTO_ENCODE_CHECK_BOUNDS(pos, 5);
     pos[0] = tag;
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-    std::memcpy(pos + 1, &value, 4);
-#else
-    pos[1] = static_cast<uint8_t>(value & 0xFF);
-    pos[2] = static_cast<uint8_t>((value >> 8) & 0xFF);
-    pos[3] = static_cast<uint8_t>((value >> 16) & 0xFF);
-    pos[4] = static_cast<uint8_t>((value >> 24) & 0xFF);
-#endif
-    pos += 5;
+    write_fixed32_le(pos + 1, value);
+    return pos + 5;
   }
-  static inline void encode_string(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id,
-                                   const char *string, size_t len, bool force = false) {
-    if (len == 0 && !force)
-      return;
-    encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 2);  // type 2: Length-delimited string
+  [[nodiscard]] static inline uint8_t *encode_string_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                           uint32_t field_id, const char *string, size_t len) {
+    pos = encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 2);  // type 2: Length-delimited string
     // NOLINTNEXTLINE(readability-inconsistent-ifelse-braces) -- false positive on [[likely]] attribute
     if (len < VARINT_MAX_1_BYTE) [[likely]] {
       PROTO_ENCODE_CHECK_BOUNDS(pos, 1 + len);
       *pos++ = static_cast<uint8_t>(len);
     } else {
-      encode_varint_raw_loop(pos PROTO_ENCODE_DEBUG_ARG, len);
+      pos = encode_varint_raw_loop(pos PROTO_ENCODE_DEBUG_ARG, len);
       PROTO_ENCODE_CHECK_BOUNDS(pos, len);
     }
     std::memcpy(pos, string, len);
-    pos += len;
+    return pos + len;
   }
-  static inline void encode_string(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id,
-                                   const std::string &value, bool force = false) {
-    encode_string(pos PROTO_ENCODE_DEBUG_ARG, field_id, value.data(), value.size(), force);
+  [[nodiscard]] static inline uint8_t *encode_string(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                     uint32_t field_id, const char *string, size_t len) {
+    if (len == 0)
+      return pos;
+    return encode_string_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, string, len);
   }
-  static inline void encode_string(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id,
-                                   const StringRef &ref, bool force = false) {
-    encode_string(pos PROTO_ENCODE_DEBUG_ARG, field_id, ref.c_str(), ref.size(), force);
+  [[nodiscard]] static inline uint8_t *encode_string_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                           uint32_t field_id, const std::string &value) {
+    return encode_string_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, value.data(), value.size());
   }
-  static inline void encode_bytes(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id,
-                                  const uint8_t *data, size_t len, bool force = false) {
-    encode_string(pos PROTO_ENCODE_DEBUG_ARG, field_id, reinterpret_cast<const char *>(data), len, force);
+  [[nodiscard]] static inline uint8_t *encode_string(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                     uint32_t field_id, const StringRef &ref) {
+    return encode_string(pos PROTO_ENCODE_DEBUG_ARG, field_id, ref.c_str(), ref.size());
   }
-  static inline void encode_uint32(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id,
-                                   uint32_t value, bool force = false) {
-    if (value == 0 && !force)
-      return;
-    encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 0);
-    encode_varint_raw(pos PROTO_ENCODE_DEBUG_ARG, value);
+  [[nodiscard]] static inline uint8_t *encode_string_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                           uint32_t field_id, const StringRef &ref) {
+    return encode_string_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, ref.c_str(), ref.size());
   }
-  static inline void encode_uint64(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id,
-                                   uint64_t value, bool force = false) {
-    if (value == 0 && !force)
-      return;
-    encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 0);
-    encode_varint_raw_64(pos PROTO_ENCODE_DEBUG_ARG, value);
+  [[nodiscard]] static inline uint8_t *encode_bytes(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                    uint32_t field_id, const uint8_t *data, size_t len) {
+    return encode_string(pos PROTO_ENCODE_DEBUG_ARG, field_id, reinterpret_cast<const char *>(data), len);
   }
-  static inline void encode_bool(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, bool value,
-                                 bool force = false) {
-    if (!value && !force)
-      return;
-    encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 0);
+  [[nodiscard]] static inline uint8_t *encode_bytes_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                          uint32_t field_id, const uint8_t *data, size_t len) {
+    return encode_string_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, reinterpret_cast<const char *>(data), len);
+  }
+  [[nodiscard]] static inline uint8_t *encode_uint32_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                           uint32_t field_id, uint32_t value) {
+    pos = encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 0);
+    return encode_varint_raw(pos PROTO_ENCODE_DEBUG_ARG, value);
+  }
+  [[nodiscard]] static inline uint8_t *encode_uint32(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                     uint32_t field_id, uint32_t value) {
+    if (value == 0)
+      return pos;
+    return encode_uint32_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, value);
+  }
+  [[nodiscard]] static inline uint8_t *encode_uint64_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                           uint32_t field_id, uint64_t value) {
+    pos = encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 0);
+    return encode_varint_raw_64(pos PROTO_ENCODE_DEBUG_ARG, value);
+  }
+  [[nodiscard]] static inline uint8_t *encode_uint64(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                     uint32_t field_id, uint64_t value) {
+    if (value == 0)
+      return pos;
+    return encode_uint64_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, value);
+  }
+  [[nodiscard]] static inline uint8_t *encode_bool_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                         uint32_t field_id, bool value) {
+    pos = encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 0);
     PROTO_ENCODE_CHECK_BOUNDS(pos, 1);
     *pos++ = value ? 0x01 : 0x00;
+    return pos;
   }
-  static inline void encode_fixed32(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id,
-                                    uint32_t value, bool force = false) {
-    if (value == 0 && !force)
-      return;
-    encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 5);
+  [[nodiscard]] static inline uint8_t *encode_bool(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                   uint32_t field_id, bool value) {
+    if (!value)
+      return pos;
+    return encode_bool_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, value);
+  }
+  /// Tag + fixed32 for multi-byte tags; single-byte tags use write_tag_and_fixed32.
+  [[nodiscard]] static PROTO_OUTLINE_FOR_SIZE uint8_t *encode_fixed32_force(
+      uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, uint32_t value) {
+    pos = encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 5);
     PROTO_ENCODE_CHECK_BOUNDS(pos, 4);
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-    std::memcpy(pos, &value, 4);
-    pos += 4;
-#else
-    *pos++ = (value >> 0) & 0xFF;
-    *pos++ = (value >> 8) & 0xFF;
-    *pos++ = (value >> 16) & 0xFF;
-    *pos++ = (value >> 24) & 0xFF;
-#endif
+    write_fixed32_le(pos, value);
+    return pos + 4;
+  }
+  [[nodiscard]] static inline uint8_t *encode_fixed32(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                      uint32_t field_id, uint32_t value) {
+    if (value == 0)
+      return pos;
+    return encode_fixed32_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, value);
   }
   // NOTE: Wire type 1 (64-bit fixed: double, fixed64, sfixed64) is intentionally
   // not supported to reduce overhead on embedded systems. All ESPHome devices are
   // 32-bit microcontrollers where 64-bit operations are expensive. If 64-bit support
   // is needed in the future, the necessary encoding/decoding functions must be added.
-  static inline void encode_float(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, float value,
-                                  bool force = false) {
-    uint32_t raw = float_to_raw(value);
-    if (raw == 0 && !force)
-      return;
-    encode_fixed32(pos PROTO_ENCODE_DEBUG_ARG, field_id, raw);
+  [[nodiscard]] static inline uint8_t *encode_float(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                    uint32_t field_id, float value) {
+    return encode_fixed32(pos PROTO_ENCODE_DEBUG_ARG, field_id, float_to_raw(value));
   }
-  static inline void encode_int32(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, int32_t value,
-                                  bool force = false) {
+  [[nodiscard]] static inline uint8_t *encode_float_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                          uint32_t field_id, float value) {
+    return encode_fixed32_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, float_to_raw(value));
+  }
+  [[nodiscard]] static inline uint8_t *encode_int32_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                          uint32_t field_id, int32_t value) {
     if (value < 0) {
       // negative int32 is always 10 byte long
-      encode_uint64(pos PROTO_ENCODE_DEBUG_ARG, field_id, static_cast<uint64_t>(value), force);
-      return;
+      return encode_uint64_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, static_cast<uint64_t>(value));
     }
-    encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, field_id, static_cast<uint32_t>(value), force);
+    return encode_uint32_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, static_cast<uint32_t>(value));
   }
-  static inline void encode_int64(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, int64_t value,
-                                  bool force = false) {
-    encode_uint64(pos PROTO_ENCODE_DEBUG_ARG, field_id, static_cast<uint64_t>(value), force);
+  [[nodiscard]] static inline uint8_t *encode_int32(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                    uint32_t field_id, int32_t value) {
+    if (value == 0)
+      return pos;
+    return encode_int32_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, value);
   }
-  static inline void encode_sint32(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id,
-                                   int32_t value, bool force = false) {
-    encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, field_id, encode_zigzag32(value), force);
+  [[nodiscard]] static inline uint8_t *encode_int64(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                    uint32_t field_id, int64_t value) {
+    return encode_uint64(pos PROTO_ENCODE_DEBUG_ARG, field_id, static_cast<uint64_t>(value));
   }
-  static inline void encode_sint64(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id,
-                                   int64_t value, bool force = false) {
-    encode_uint64(pos PROTO_ENCODE_DEBUG_ARG, field_id, encode_zigzag64(value), force);
+  [[nodiscard]] static inline uint8_t *encode_int64_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                          uint32_t field_id, int64_t value) {
+    return encode_uint64_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, static_cast<uint64_t>(value));
   }
-  /// Sub-message encoding: sync pos to buffer, delegate, get pos from return value.
+  [[nodiscard]] static inline uint8_t *encode_sint32(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                     uint32_t field_id, int32_t value) {
+    return encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, field_id, encode_zigzag32(value));
+  }
+  [[nodiscard]] static inline uint8_t *encode_sint32_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                           uint32_t field_id, int32_t value) {
+    return encode_uint32_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, encode_zigzag32(value));
+  }
+  [[nodiscard]] static inline uint8_t *encode_sint64(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                     uint32_t field_id, int64_t value) {
+    return encode_uint64(pos PROTO_ENCODE_DEBUG_ARG, field_id, encode_zigzag64(value));
+  }
+  [[nodiscard]] static inline uint8_t *encode_sint64_force(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                           uint32_t field_id, int64_t value) {
+    return encode_uint64_force(pos PROTO_ENCODE_DEBUG_ARG, field_id, encode_zigzag64(value));
+  }
+  /// Sub-message encoding: sync pos to buffer, delegate, read the cursor back.
   template<typename T>
-  static inline void encode_sub_message(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, ProtoWriteBuffer &buffer,
-                                        uint32_t field_id, const T &value) {
+  [[nodiscard]] static inline uint8_t *encode_sub_message(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                          ProtoWriteBuffer &buffer, uint32_t field_id, const T &value) {
     buffer.set_pos(pos);
     buffer.encode_sub_message(field_id, value);
-    pos = buffer.get_pos();
+    return buffer.get_pos();
   }
   template<typename T>
-  static inline void encode_optional_sub_message(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM,
-                                                 ProtoWriteBuffer &buffer, uint32_t field_id, const T &value) {
+  [[nodiscard]] static inline uint8_t *encode_optional_sub_message(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
+                                                                   ProtoWriteBuffer &buffer, uint32_t field_id,
+                                                                   const T &value) {
     buffer.set_pos(pos);
     buffer.encode_optional_sub_message(field_id, value);
-    pos = buffer.get_pos();
+    return buffer.get_pos();
   }
 };
+#undef PROTO_OUTLINE_FOR_SIZE
+#undef PROTO_FIXED32_BYTE_STORES
 
 #ifdef HAS_PROTO_MESSAGE_DUMP
 /**

esphome/components/esp32/__init__.py

@@ -3343,12 +3343,7 @@ def _write_idf_component_yml():
             # Don't process arduino libraries
             if name not in ARDUINO_DISABLED_LIBRARIES
         ]
-        # A library that is also declared as a managed component must not be
-        # converted as well, or IDF sees the same requirement from two
-        # components and refuses to build. Converted components still link
-        # against it via ${ESPHOME_PROJECT_MANAGED_COMPONENTS}.
-        managed = set(CORE.data[KEY_ESP32].get(KEY_COMPONENTS, {}))
-        for component in generate_idf_components(libraries, managed=managed):
+        for component in generate_idf_components(libraries):
             dependencies[component.get_sanitized_name()] = {
                 "override_path": str(component.path)
             }

esphome/components/esp32_hosted/__init__.py

@@ -37,6 +37,25 @@ CONF_HANDSHAKE_PIN = "handshake_pin"
 CONF_SDIO_FREQUENCY = "sdio_frequency"
 CONF_SPI_MODE = "spi_mode"
 
+# ESP-NOW-over-hosted shim (esp_now_hosted.cpp). esp-hosted proxies esp_wifi.h
+# but not esp_now.h (espressif/esp-hosted-mcu#19), and esp_wifi_remote injects
+# the esp_now.h header on the ESP32-P4 host with no implementation, leaving the
+# esp_now_* symbols undefined at link. On a P4 host, esp_now_hosted.cpp DEFINES
+# those symbols and forwards each call to the co-processor over esp-hosted's
+# CustomRpc "peer data transfer" channel, so ESPHome's `espnow` component links
+# and runs unchanged (proven on a Tab5, 2026-07-20). The .cpp is guarded to
+# CONFIG_IDF_TARGET_ESP32P4 so it compiles to nothing on hosts with a native
+# ESP-NOW stack. CustomRpc needs these two host-side Kconfig options. Host
+# registers 3 handlers (RESP, RECV, SEND); the coprocessor registers 1 (REQ);
+# we ask for 8 to leave room for other CustomRpc extensions alongside.
+#
+# The coprocessor must run the matching custom firmware (a parallel effort in
+# esphome/esp-hosted-firmware). esp_now_hosted_rpc.h here is the canonical copy
+# of the wire contract and MUST stay byte-identical to the copy that coprocessor
+# firmware uses — the packed structs are the on-wire layout, so any divergence
+# silently corrupts every ESP-NOW frame.
+_MAX_CUSTOM_MSG_HANDLERS = 8
+
 # Shared fields for both transport modes
 BASE_SCHEMA = cv.Schema(
     {
@@ -262,6 +281,23 @@ async def to_code(config: ConfigType) -> None:
     else:
         _configure_spi(config)
 
+    # ESP-NOW-over-hosted shim: only the radio-less ESP32-P4 host needs it (see
+    # the note by _MAX_CUSTOM_MSG_HANDLERS). Enabled for every P4 host, not
+    # gated on the `espnow` component being present: the shim is tiny and the
+    # esp_now_* symbols/CustomRpc calls it defines require these Kconfig options
+    # to link whenever esp_now_hosted.cpp compiles (which is on any P4 host), so
+    # coupling the two keeps the build consistent. When `espnow` is absent the
+    # symbols are simply unused and never register a callback at runtime.
+    if esp32.get_esp32_variant() == esp32.VARIANT_ESP32P4:
+        add_define("USE_ESP_NOW_HOSTED")
+        # esp-hosted's CustomRpc ("peer data transfer") path — off by default.
+        esp32.add_idf_sdkconfig_option(
+            "CONFIG_ESP_HOSTED_ENABLE_PEER_DATA_TRANSFER", True
+        )
+        esp32.add_idf_sdkconfig_option(
+            "CONFIG_ESP_HOSTED_MAX_CUSTOM_MSG_HANDLERS", _MAX_CUSTOM_MSG_HANDLERS
+        )
+
     # Place the transport mempool in PSRAM. Required on memory-tight host
     # configurations (e.g. P4 with a large LVGL UI) where the internal-RAM
     # mempool allocation fails at boot with `sdio_mempool_create` assert.

esphome/components/esp32_hosted/esp_now_hosted.cpp

@@ -0,0 +1,467 @@
+/*
+ * esp_now_hosted — host-side shim implementing <esp_now.h> over esp-hosted
+ * CustomRpc, so ESPHome's `espnow` component can run on a radio-less host
+ * (e.g. the ESP32-P4) whose radio lives on an esp-hosted co-processor.
+ *
+ * A radio-less host has no native ESP-NOW. esp_wifi_remote INJECTS the full
+ * esp_now.h header (types + declarations) but ships NO implementation, so every
+ * esp_now_* symbol is an undefined reference at link time. This translation
+ * unit provides those definitions; each forwards to the co-processor over
+ * CustomRpc (see esphome/esp-hosted-firmware for the matching coprocessor
+ * handlers). No esp-hosted or esp_wifi_remote source is patched, and there is no
+ * duplicate-symbol clash because nothing else defines these symbols here.
+ *
+ * See esp_now_hosted_rpc.h for the wire protocol.
+ */
+
+#include "sdkconfig.h"
+
+// Only build the shim on the radio-less host. On chips with a native ESP-NOW
+// stack (S3, C6, …) the real symbols exist and this file must stay empty to
+// avoid duplicate definitions.
+#if defined(CONFIG_IDF_TARGET_ESP32P4)
+
+#include <cstring>
+
+#include "freertos/FreeRTOS.h"
+#include "freertos/semphr.h"
+
+#include "esp_idf_version.h"
+#include "esp_log.h"
+#include "esp_timer.h"
+
+#include <esp_now.h>         // injected declarations we are now DEFINING
+#include <esp_wifi_types.h>  // wifi_pkt_rx_ctrl_t, wifi_tx_info_t
+
+// esp_hosted_misc.h (host) ships WITHOUT an extern "C" guard, so including it
+// from C++ would give its declarations C++ linkage and the real C symbols in
+// libesp_hosted would go unresolved at link. Wrap it. (Verified vs
+// esp_hosted 2.12.9.)
+extern "C" {
+#include "esp_hosted_misc.h"  // esp_hosted_{send_custom_data,register_custom_callback}
+}
+
+#include "esp_now_hosted_rpc.h"
+
+namespace {
+
+const char *const TAG = "esp_now_hosted";
+
+// One outstanding request at a time. ESPHome drives esp_now_* from the main
+// loop; the matching response and the async RECV/SEND events all arrive on the
+// single esp-hosted RPC RX thread. Serializing requests keeps the shared
+// response slot race-free; a sequence number stops a late/stale response from
+// being mistaken for ours.
+SemaphoreHandle_t g_req_mutex = nullptr;
+SemaphoreHandle_t g_resp_sem = nullptr;  // given when the matching RESP lands
+bool g_setup_done = false;               // set only after setup fully succeeds
+uint8_t g_seq = 0;
+volatile uint8_t g_expect_seq = 0;
+volatile int32_t g_resp_status = 0;
+uint8_t g_resp_ret[16];
+volatile uint16_t g_resp_ret_len = 0;
+
+// Written from the main loop (register/unregister/deinit), read from the
+// esp-hosted RX thread (on_recv/on_send). volatile for the same reason the
+// g_resp_* globals are: force the RX thread to observe an updated pointer
+// (e.g. a nulling by esp_now_deinit) rather than a cached one.
+volatile esp_now_recv_cb_t g_recv_cb = nullptr;
+volatile esp_now_send_cb_t g_send_cb = nullptr;
+
+// Local mirror of the co-processor's peer table. ESPHome's espnow component
+// calls esp_now_is_peer_exist() on the main loop for every received frame
+// (twice) and every send; forwarding each as a blocking RPC round-trip stalls
+// the loop. The shim is the only path that mutates the co-processor peer table
+// (add/del/deinit all go through here), so this mirror is authoritative and
+// esp_now_is_peer_exist() can answer from it with no round-trip.
+//
+// esp_now_* are public C symbols: any component or user lambda may call them,
+// and although ESPHome's espnow touches peers only from the main loop today
+// (its RX/TX callbacks merely enqueue), the shim cannot rely on that. A short
+// spinlock keeps the mirror consistent from any task/core, matching native
+// esp_now_*'s own internal thread-safety. The critical sections are a bounded
+// (<=20-entry) scan, so they stay tiny. ESP_NOW_MAX_TOTAL_PEER_NUM is 20.
+constexpr size_t ESP_NOW_HOSTED_MAX_PEERS = 20;
+uint8_t g_peer_cache[ESP_NOW_HOSTED_MAX_PEERS][6];
+size_t g_peer_count = 0;
+portMUX_TYPE g_peer_lock = portMUX_INITIALIZER_UNLOCKED;
+
+// Caller must hold g_peer_lock.
+int peer_cache_find_locked(const uint8_t *mac) {
+  for (size_t i = 0; i < g_peer_count; i++) {
+    if (memcmp(g_peer_cache[i], mac, 6) == 0)
+      return static_cast<int>(i);
+  }
+  return -1;
+}
+
+bool peer_cache_contains(const uint8_t *mac) {
+  portENTER_CRITICAL(&g_peer_lock);
+  const bool found = peer_cache_find_locked(mac) >= 0;
+  portEXIT_CRITICAL(&g_peer_lock);
+  return found;
+}
+
+void peer_cache_add(const uint8_t *mac) {
+  portENTER_CRITICAL(&g_peer_lock);
+  if (peer_cache_find_locked(mac) < 0 && g_peer_count < ESP_NOW_HOSTED_MAX_PEERS)
+    memcpy(g_peer_cache[g_peer_count++], mac, 6);
+  portEXIT_CRITICAL(&g_peer_lock);
+}
+
+void peer_cache_remove(const uint8_t *mac) {
+  portENTER_CRITICAL(&g_peer_lock);
+  const int idx = peer_cache_find_locked(mac);
+  if (idx >= 0) {
+    g_peer_count--;
+    if (static_cast<size_t>(idx) != g_peer_count)  // move the last entry into the gap
+      memcpy(g_peer_cache[idx], g_peer_cache[g_peer_count], 6);
+  }
+  portEXIT_CRITICAL(&g_peer_lock);
+}
+
+void peer_cache_clear() {
+  portENTER_CRITICAL(&g_peer_lock);
+  g_peer_count = 0;
+  portEXIT_CRITICAL(&g_peer_lock);
+}
+
+// ── CustomRpc event handlers (run on the esp-hosted RPC RX thread) ──────────
+// Keep them short and non-blocking. In particular they MUST NOT call back into
+// any esp_now_* shim function: that would try to take g_req_mutex / wait on the
+// RX thread that delivers the response, and deadlock.
+
+void on_resp(uint32_t /*msg_id*/, const uint8_t *data, size_t len, void * /*ctx*/) {
+  if (len < sizeof(esp_now_hosted_resp_t)) {
+    ESP_LOGW(TAG, "RESP too short: %u bytes", static_cast<unsigned>(len));
+    return;
+  }
+  const auto *r = reinterpret_cast<const esp_now_hosted_resp_t *>(data);
+  if (r->seq != g_expect_seq) {  // late response from a timed-out request (expected)
+    ESP_LOGV(TAG, "dropping stale RESP seq %u (want %u)", r->seq, g_expect_seq);
+    return;
+  }
+  g_resp_status = r->status;
+  uint16_t rl = r->ret_len;
+  if (rl > sizeof(g_resp_ret)) {
+    // Larger than any real opcode return — a likely wire-format drift signal.
+    ESP_LOGW(TAG, "RESP ret_len %u exceeds buffer, clamping (wire drift?)", rl);
+    rl = sizeof(g_resp_ret);
+  }
+  if (len >= sizeof(esp_now_hosted_resp_t) + rl) {
+    memcpy(g_resp_ret, r->ret, rl);
+  } else {
+    // Truncated frame: fail closed. Never hand the caller stale bytes left in
+    // g_resp_ret by a previous response, and don't let request() report a
+    // zeroed payload as success — override the status to an error.
+    ESP_LOGW(TAG, "RESP truncated: claims %u ret bytes, frame too short", rl);
+    rl = 0;
+    g_resp_status = ESP_ERR_INVALID_RESPONSE;
+  }
+  g_resp_ret_len = rl;
+  xSemaphoreGive(g_resp_sem);
+}
+
+void on_recv(uint32_t /*msg_id*/, const uint8_t *data, size_t len, void * /*ctx*/) {
+  // Read the volatile pointer once: esp_now_unregister_recv_cb()/deinit() (via
+  // the espnow component's disable()) can null it on the main loop between the
+  // guard and the call, which would otherwise turn the call into a null-deref.
+  const esp_now_recv_cb_t cb = g_recv_cb;
+  if (cb == nullptr)
+    return;
+  if (len < sizeof(esp_now_hosted_recv_evt_t)) {
+    ESP_LOGW(TAG, "RECV too short: %u bytes", static_cast<unsigned>(len));
+    return;
+  }
+  const auto *e = reinterpret_cast<const esp_now_hosted_recv_evt_t *>(data);
+  if (len < sizeof(esp_now_hosted_recv_evt_t) + e->data_len) {
+    ESP_LOGW(TAG, "RECV data_len %u exceeds frame", e->data_len);
+    return;
+  }
+
+  // ESPHome dereferences info->rx_ctrl->{rssi,timestamp}; give it a real one.
+  wifi_pkt_rx_ctrl_t rx_ctrl;
+  memset(&rx_ctrl, 0, sizeof(rx_ctrl));
+  rx_ctrl.rssi = e->rssi;
+  rx_ctrl.channel = e->channel;
+  rx_ctrl.timestamp = static_cast<uint32_t>(esp_timer_get_time());
+
+  esp_now_recv_info_t info;
+  info.src_addr = const_cast<uint8_t *>(e->src_addr);
+  info.des_addr = const_cast<uint8_t *>(e->des_addr);
+  info.rx_ctrl = &rx_ctrl;
+  cb(&info, e->data, static_cast<int>(e->data_len));
+}
+
+void on_send(uint32_t /*msg_id*/, const uint8_t *data, size_t len, void * /*ctx*/) {
+  // Read the volatile pointer once (see on_recv): disable()/deinit() can null it
+  // on the main loop concurrently with this RX-thread callback.
+  const esp_now_send_cb_t cb = g_send_cb;
+  if (cb == nullptr)
+    return;
+  if (len < sizeof(esp_now_hosted_send_evt_t)) {
+    ESP_LOGW(TAG, "SEND evt too short: %u bytes", static_cast<unsigned>(len));
+    return;
+  }
+  const auto *e = reinterpret_cast<const esp_now_hosted_send_evt_t *>(data);
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 5, 0)
+  // IDF >= 5.5: esp_now_send_cb_t takes esp_now_send_info_t (== wifi_tx_info_t),
+  // whose des_addr is a POINTER (not an inline array). Point it at the event's
+  // MAC (valid for this callback) — do NOT memcpy into it (that writes NULL and
+  // faults). ESPHome reads only info->des_addr.
+  esp_now_send_info_t si;
+  memset(&si, 0, sizeof(si));
+  si.des_addr = const_cast<uint8_t *>(e->des_addr);
+  cb(&si, static_cast<esp_now_send_status_t>(e->status));
+#else
+  cb(e->des_addr, static_cast<esp_now_send_status_t>(e->status));
+#endif
+}
+
+esp_err_t ensure_setup() {
+  // Gate on g_setup_done, not on g_req_mutex: a failure part-way through (a
+  // semaphore that did not allocate, a callback that did not register) must not
+  // leave a later call thinking setup completed. Semaphore creation is guarded
+  // so a retry after a partial failure does not leak the earlier handles.
+  if (g_setup_done)
+    return ESP_OK;
+  if (g_req_mutex == nullptr)
+    g_req_mutex = xSemaphoreCreateMutex();
+  if (g_resp_sem == nullptr)
+    g_resp_sem = xSemaphoreCreateBinary();
+  if (g_req_mutex == nullptr || g_resp_sem == nullptr)
+    return ESP_ERR_NO_MEM;
+  esp_err_t err;
+  if ((err = esp_hosted_register_custom_callback(ESP_NOW_HOSTED_MSG_RESP, on_resp, nullptr)) != ESP_OK)
+    return err;
+  if ((err = esp_hosted_register_custom_callback(ESP_NOW_HOSTED_MSG_RECV, on_recv, nullptr)) != ESP_OK)
+    return err;
+  if ((err = esp_hosted_register_custom_callback(ESP_NOW_HOSTED_MSG_SEND, on_send, nullptr)) != ESP_OK)
+    return err;
+  g_setup_done = true;
+  return ESP_OK;
+}
+
+// Send one request envelope. With wait=true (default) block until the matching
+// response (or timeout); with wait=false return as soon as the frame is handed
+// to the transport (fire-and-forget, used by esp_now_send).
+//
+// `tail` is an optional second chunk written straight after `payload`. Callers
+// with a fixed header plus a bulk body (esp_now_send) pass the two separately
+// so they never need a build buffer of their own: both chunks are laid into the
+// request buffer here, under g_req_mutex, which keeps concurrent callers from
+// racing and saves a full copy of the body on every transmit.
+esp_err_t request(uint8_t opcode, const void *payload, uint16_t plen, void *ret, uint16_t ret_cap, uint16_t *ret_len,
+                  bool wait = true, const void *tail = nullptr, uint16_t tail_len = 0) {
+  esp_err_t err = ensure_setup();
+  if (err != ESP_OK)
+    return err;
+  if (plen > ESP_NOW_HOSTED_MAX_PAYLOAD || tail_len > ESP_NOW_HOSTED_MAX_PAYLOAD - plen)
+    return ESP_ERR_INVALID_SIZE;
+  const uint16_t total_len = static_cast<uint16_t>(plen + tail_len);
+
+  if (xSemaphoreTake(g_req_mutex, portMAX_DELAY) != pdTRUE)
+    return ESP_FAIL;
+
+  static uint8_t buf[sizeof(esp_now_hosted_req_t) + ESP_NOW_HOSTED_MAX_PAYLOAD];  // guarded by g_req_mutex
+  auto *req = reinterpret_cast<esp_now_hosted_req_t *>(buf);
+  req->opcode = opcode;
+  req->seq = ++g_seq;
+  req->payload_len = total_len;
+  if (plen != 0)
+    memcpy(req->payload, payload, plen);
+  if (tail_len != 0)
+    memcpy(req->payload + plen, tail, tail_len);
+  g_expect_seq = req->seq;
+
+  xSemaphoreTake(g_resp_sem, 0);  // drain any stale signal before sending
+  err = esp_hosted_send_custom_data(ESP_NOW_HOSTED_MSG_REQ, buf, sizeof(esp_now_hosted_req_t) + total_len);
+  if (err != ESP_OK) {
+    xSemaphoreGive(g_req_mutex);
+    return err;
+  }
+  if (!wait) {
+    // Fire-and-forget (esp_now_send): the co-processor enqueues the frame and
+    // reports the real TX result later via the async SEND event, exactly like
+    // native esp_now_send. Returning here keeps the main loop off the ~100 ms+
+    // RPC round-trip. The matching RESP is ignored (seq won't match the next
+    // waited request, so on_resp drops it).
+    xSemaphoreGive(g_req_mutex);
+    return ESP_OK;
+  }
+  if (xSemaphoreTake(g_resp_sem, pdMS_TO_TICKS(ESP_NOW_HOSTED_TIMEOUT_MS)) != pdTRUE) {
+    ESP_LOGW(TAG, "opcode %u timed out", opcode);
+    xSemaphoreGive(g_req_mutex);
+    return ESP_ERR_TIMEOUT;
+  }
+
+  const int32_t status = g_resp_status;
+  if (ret != nullptr && ret_cap != 0) {
+    uint16_t n = g_resp_ret_len < ret_cap ? g_resp_ret_len : ret_cap;
+    memcpy(ret, const_cast<const uint8_t *>(g_resp_ret), n);
+    if (ret_len != nullptr)
+      *ret_len = n;
+  }
+  xSemaphoreGive(g_req_mutex);
+  return static_cast<esp_err_t>(status);
+}
+
+}  // namespace
+
+// ── The <esp_now.h> surface, defined for the radio-less host ────────────────
+extern "C" {
+
+esp_err_t esp_now_init(void) { return request(ESP_NOW_HOSTED_OP_INIT, nullptr, 0, nullptr, 0, nullptr); }
+
+esp_err_t esp_now_deinit(void) {
+  g_recv_cb = nullptr;
+  g_send_cb = nullptr;
+  peer_cache_clear();  // the co-processor drops all peers on deinit
+  return request(ESP_NOW_HOSTED_OP_DEINIT, nullptr, 0, nullptr, 0, nullptr);
+}
+
+esp_err_t esp_now_get_version(uint32_t *version) {
+  uint32_t v = 0;
+  uint16_t rl = 0;
+  esp_err_t err = request(ESP_NOW_HOSTED_OP_GET_VERSION, nullptr, 0, &v, sizeof(v), &rl);
+  if (version != nullptr)
+    *version = v;
+  return err;
+}
+
+esp_err_t esp_now_register_recv_cb(esp_now_recv_cb_t cb) {
+  // Only arm the callback once the CustomRpc handlers are actually registered,
+  // so a failed setup leaves g_recv_cb null rather than falsely "registered".
+  esp_err_t err = ensure_setup();
+  if (err != ESP_OK)
+    return err;
+  g_recv_cb = cb;
+  return ESP_OK;
+}
+esp_err_t esp_now_unregister_recv_cb(void) {
+  g_recv_cb = nullptr;
+  return ESP_OK;
+}
+esp_err_t esp_now_register_send_cb(esp_now_send_cb_t cb) {
+  esp_err_t err = ensure_setup();
+  if (err != ESP_OK)
+    return err;
+  g_send_cb = cb;
+  return ESP_OK;
+}
+esp_err_t esp_now_unregister_send_cb(void) {
+  g_send_cb = nullptr;
+  return ESP_OK;
+}
+
+static esp_err_t add_or_mod_peer(uint8_t opcode, const esp_now_peer_info_t *peer, bool wait) {
+  if (peer == nullptr)
+    return ESP_ERR_ESPNOW_ARG;
+  esp_now_hosted_peer_t p;
+  memset(&p, 0, sizeof(p));
+  memcpy(p.peer_addr, peer->peer_addr, 6);
+  memcpy(p.lmk, peer->lmk, 16);
+  p.channel = peer->channel;
+  p.ifidx = static_cast<uint8_t>(peer->ifidx);
+  p.encrypt = peer->encrypt ? 1 : 0;
+  return request(opcode, &p, sizeof(p), nullptr, 0, nullptr, wait);
+}
+esp_err_t esp_now_add_peer(const esp_now_peer_info_t *peer) {
+  // Fire-and-forget (wait=false): adding a peer is a blocking RPC round-trip,
+  // and ESPHome's espnow calls it on the main loop when a device joins the mesh
+  // — under co-processor load that stalls the UI (peer-churn stutter). Issue it
+  // without waiting and mirror it locally. Safe against a following
+  // esp_now_send to the same peer: both ride the same in-order CustomRpc
+  // channel (mutex-serialized on the host) and the co-processor processes REQs
+  // FIFO, so ADD_PEER is applied before the SEND. Trade-off: a co-processor-side
+  // failure (e.g. peer table full) is no longer reported synchronously — the
+  // same limitation as esp_now_send — but ESPHome only adds peers it validated.
+  esp_err_t err = add_or_mod_peer(ESP_NOW_HOSTED_OP_ADD_PEER, peer, /*wait=*/false);
+  if (err == ESP_OK)
+    peer_cache_add(peer->peer_addr);  // keep the local mirror in sync
+  return err;
+}
+esp_err_t esp_now_mod_peer(const esp_now_peer_info_t *peer) {
+  // mod_peer changes a peer's parameters, not its existence, so the cache is
+  // unaffected. Kept synchronous — it is not on any hot path (espnow never
+  // calls it), so the extra round-trip does not matter and the status is useful.
+  return add_or_mod_peer(ESP_NOW_HOSTED_OP_MOD_PEER, peer, /*wait=*/true);
+}
+
+esp_err_t esp_now_del_peer(const uint8_t *peer_addr) {
+  if (peer_addr == nullptr)
+    return ESP_ERR_ESPNOW_ARG;
+  // Fire-and-forget for the same reason as add_peer (peer churn on the main
+  // loop). Removal is order-independent, so this is strictly safe.
+  esp_err_t err = request(ESP_NOW_HOSTED_OP_DEL_PEER, peer_addr, 6, nullptr, 0, nullptr, /*wait=*/false);
+  if (err == ESP_OK)
+    peer_cache_remove(peer_addr);  // keep the local mirror in sync
+  return err;
+}
+
+bool esp_now_is_peer_exist(const uint8_t *peer_addr) {
+  if (peer_addr == nullptr)
+    return false;
+  // Answered from the local mirror — no RPC round-trip. ESPHome's espnow calls
+  // this on the main loop for every received frame and every send, so a
+  // blocking round-trip here would stall rendering under mesh traffic.
+  return peer_cache_contains(peer_addr);
+}
+
+esp_err_t esp_now_send(const uint8_t *peer_addr, const uint8_t *data, size_t len) {
+  if (len > ESP_NOW_HOSTED_MAX_FRAME)
+    return ESP_ERR_ESPNOW_ARG;
+  if (data == nullptr && len != 0)  // native esp_now_send treats this as an arg error
+    return ESP_ERR_ESPNOW_ARG;
+  // Only the small fixed header is built here; the caller's frame goes over as
+  // the request tail, so request() lays both into its own buffer under
+  // g_req_mutex. esp_now_send is a public C symbol and may be called from any
+  // task, and a shared build buffer here would let two callers corrupt each
+  // other's frame. Passing the body through also drops a full-frame copy per
+  // transmit, on the path this shim exists to keep quick.
+  uint8_t hdr[sizeof(esp_now_hosted_send_req_t)];
+  auto *s = reinterpret_cast<esp_now_hosted_send_req_t *>(hdr);
+  s->has_addr = peer_addr != nullptr ? 1 : 0;
+  if (peer_addr != nullptr)
+    memcpy(s->peer_addr, peer_addr, 6);
+  else
+    memset(s->peer_addr, 0, 6);
+  s->data_len = static_cast<uint16_t>(len);
+  // Fire-and-forget (wait=false): native esp_now_send returns once the frame is
+  // queued, with the real TX result delivered later through the send callback.
+  // The co-processor mirrors that — it acks enqueue immediately and reports the
+  // outcome via the async SEND event (on_send -> on_send_report). Waiting for
+  // the RPC RESP here would block the main loop for the full round-trip on
+  // every transmit.
+  return request(ESP_NOW_HOSTED_OP_SEND, hdr, sizeof(hdr), nullptr, 0, nullptr, /*wait=*/false, data,
+                 static_cast<uint16_t>(len));
+}
+
+esp_err_t esp_now_set_pmk(const uint8_t *pmk) {
+  if (pmk == nullptr)
+    return ESP_ERR_ESPNOW_ARG;
+  return request(ESP_NOW_HOSTED_OP_SET_PMK, pmk, 16, nullptr, 0, nullptr);
+}
+
+// Remainder of the <esp_now.h> surface. Not used by ESPHome's espnow component
+// today; provided so the whole header links and future callers get a defined
+// (if unimplemented) symbol rather than a link error. Wire them through
+// CustomRpc if a use case appears.
+esp_err_t esp_now_get_peer(const uint8_t * /*peer_addr*/, esp_now_peer_info_t * /*peer*/) {
+  return ESP_ERR_NOT_SUPPORTED;
+}
+esp_err_t esp_now_fetch_peer(bool /*from_head*/, esp_now_peer_info_t * /*peer*/) { return ESP_ERR_NOT_SUPPORTED; }
+esp_err_t esp_now_get_peer_num(esp_now_peer_num_t * /*num*/) { return ESP_ERR_NOT_SUPPORTED; }
+esp_err_t esp_now_set_wake_window(uint16_t /*window*/) {
+  return ESP_ERR_NOT_SUPPORTED;  // power-save wake window is not forwarded; don't claim success
+}
+esp_err_t esp_now_set_peer_rate_config(const uint8_t * /*peer_addr*/, esp_now_rate_config_t * /*cfg*/) {
+  return ESP_ERR_NOT_SUPPORTED;
+}
+esp_err_t esp_wifi_config_espnow_rate(wifi_interface_t /*ifx*/, wifi_phy_rate_t /*rate*/) {
+  return ESP_ERR_NOT_SUPPORTED;
+}
+
+}  // extern "C"
+
+#endif  // CONFIG_IDF_TARGET_ESP32P4

esphome/components/esp32_hosted/esp_now_hosted_rpc.h

@@ -0,0 +1,128 @@
+/*
+ * esp_now_hosted — ESP-NOW-over-CustomRpc wire protocol.
+ *
+ * Shared, byte-for-byte-identical contract between:
+ *   - the host shim         (esphome/components/esp32_hosted/esp_now_hosted.cpp)
+ *   - the coprocessor firmware (esphome/esp-hosted-firmware)
+ *
+ * It rides esp-hosted's CustomRpc channel (RPC ID 388, "peer data transfer",
+ * available since esp-hosted v2.8.1), teaching the radio-less host <-> radio
+ * co-processor link to carry esp_now.h, which esp-hosted itself does not proxy
+ * (Espressif issue espressif/esp-hosted-mcu#19).
+ *
+ * KEEP THE TWO COPIES IN SYNC. The canonical copy lives here; the coprocessor
+ * firmware uses a verbatim copy. Both sides are little-endian, so these packed
+ * structs are wire-compatible with no byte-swapping.
+ */
+
+#ifndef ESP_NOW_HOSTED_RPC_H
+#define ESP_NOW_HOSTED_RPC_H
+
+#ifdef __cplusplus
+#include <cstdint>
+#else
+#include <stdint.h>
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* ── CustomRpc message IDs (any uint32_t except 0xFFFFFFFF) ──────────────────
+ * One REQ handler slot on the device; three event handler slots on the host.
+ * The bytes spell "now" + index, a private range unlikely to clash with other
+ * CustomRpc users (e.g. the stock peer_data_transfer example's 1..6).         */
+#define ESP_NOW_HOSTED_MSG_REQ 0x6E6F7701u  /* host   -> device : request envelope */
+#define ESP_NOW_HOSTED_MSG_RESP 0x6E6F7702u /* device -> host   : reply to a REQ   */
+#define ESP_NOW_HOSTED_MSG_RECV 0x6E6F7703u /* device -> host   : async RX frame   */
+#define ESP_NOW_HOSTED_MSG_SEND 0x6E6F7704u /* device -> host   : async TX status  */
+
+/* ── Request opcodes ────────────────────────────────────────────────────── */
+enum {
+  ESP_NOW_HOSTED_OP_INIT = 1,          /* esp_now_init + register device recv/send cbs */
+  ESP_NOW_HOSTED_OP_DEINIT = 2,        /* unregister cbs + esp_now_deinit             */
+  ESP_NOW_HOSTED_OP_ADD_PEER = 3,      /* payload: esp_now_hosted_peer_t              */
+  ESP_NOW_HOSTED_OP_DEL_PEER = 4,      /* payload: 6-byte peer MAC                    */
+  ESP_NOW_HOSTED_OP_IS_PEER_EXIST = 5, /* payload: 6-byte MAC; ret: 1 byte bool       */
+  ESP_NOW_HOSTED_OP_SEND = 6,          /* payload: esp_now_hosted_send_req_t          */
+  ESP_NOW_HOSTED_OP_GET_VERSION = 7,   /* ret: uint32 version                        */
+  ESP_NOW_HOSTED_OP_SET_PMK = 8,       /* payload: 16-byte PMK                        */
+  ESP_NOW_HOSTED_OP_MOD_PEER = 9,      /* payload: esp_now_hosted_peer_t              */
+};
+
+/* Largest ESP-NOW payload we forward. ESP-NOW v2 (IDF >= 5.4) is 1470 B; well
+ * under esp-hosted's 8166 B CustomRpc cap, so the shim never truncates.        */
+#define ESP_NOW_HOSTED_MAX_FRAME 1470u
+/* Envelope slack for the largest opcode payload (a SEND req wrapping a frame). */
+#define ESP_NOW_HOSTED_MAX_PAYLOAD (ESP_NOW_HOSTED_MAX_FRAME + 16u)
+/* Host request/response round-trip timeout over the transport. Generous:
+ * normal RTT is sub-millisecond, but Wi-Fi/BLE contention on the co-processor
+ * can stall the RX thread.                                                     */
+#define ESP_NOW_HOSTED_TIMEOUT_MS 2000
+
+/* ── Envelopes ──────────────────────────────────────────────────────────── */
+
+/* These payloads are shared verbatim with the C co-processor firmware, so they
+ * use C's `typedef struct {...} name;` idiom rather than C++ `using` aliases,
+ * which would not compile there. Silence clang-tidy's modernize-use-using for
+ * the shared struct block. */
+// NOLINTBEGIN(modernize-use-using)
+typedef struct {
+  uint8_t opcode;       /* one of ESP_NOW_HOSTED_OP_*                        */
+  uint8_t seq;          /* wraps 0..255; echoed in the response for matching */
+  uint16_t payload_len; /* bytes of opcode-specific payload that follow      */
+  uint8_t payload[];    /* flexible                                          */
+} __attribute__((packed)) esp_now_hosted_req_t;
+
+typedef struct {
+  uint8_t opcode;   /* echoes the request opcode                         */
+  uint8_t seq;      /* echoes the request seq                            */
+  int32_t status;   /* esp_err_t from the native call on the co-processor */
+  uint16_t ret_len; /* bytes of return payload that follow               */
+  uint8_t ret[];    /* flexible (e.g. version u32, is_peer_exist bool)   */
+} __attribute__((packed)) esp_now_hosted_resp_t;
+
+/* ── Opcode payloads ────────────────────────────────────────────────────── */
+
+/* esp_now_peer_info_t minus the host-only `priv` pointer, which is meaningless
+ * across the transport and never set by ESPHome's espnow component.           */
+typedef struct {
+  uint8_t peer_addr[6];
+  uint8_t lmk[16];
+  uint8_t channel; /* 0 = current channel                              */
+  uint8_t ifidx;   /* wifi_interface_t (0=STA, 1=AP)                    */
+  uint8_t encrypt; /* bool                                             */
+} __attribute__((packed)) esp_now_hosted_peer_t;
+
+typedef struct {
+  uint8_t has_addr; /* 0 => peer_addr is NULL (broadcast to all peers)   */
+  uint8_t peer_addr[6];
+  uint16_t data_len;
+  uint8_t data[]; /* flexible, up to ESP_NOW_HOSTED_MAX_FRAME          */
+} __attribute__((packed)) esp_now_hosted_send_req_t;
+
+/* ── Async events (device -> host) ──────────────────────────────────────── */
+
+/* Reconstructed on the host into an esp_now_recv_info_t + a minimal
+ * wifi_pkt_rx_ctrl_t. ESPHome's espnow reads info->src_addr, info->des_addr,
+ * info->rx_ctrl->rssi and info->rx_ctrl->timestamp.                           */
+typedef struct {
+  uint8_t src_addr[6];
+  uint8_t des_addr[6];
+  int8_t rssi;
+  uint8_t channel;
+  uint16_t data_len;
+  uint8_t data[]; /* flexible                                          */
+} __attribute__((packed)) esp_now_hosted_recv_evt_t;
+
+typedef struct {
+  uint8_t des_addr[6];
+  uint8_t status; /* esp_now_send_status_t (0 = success)               */
+} __attribute__((packed)) esp_now_hosted_send_evt_t;
+// NOLINTEND(modernize-use-using)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ESP_NOW_HOSTED_RPC_H */

esphome/components/espnow/__init__.py

@@ -3,6 +3,7 @@ from typing import Any
 from esphome import automation, core
 import esphome.codegen as cg
 from esphome.components import wifi
+from esphome.components.esp32 import VARIANT_ESP32P4, get_esp32_variant
 from esphome.components.udp import CONF_ON_RECEIVE
 import esphome.config_validation as cv
 from esphome.const import (
@@ -17,6 +18,7 @@ from esphome.const import (
 )
 from esphome.core import CORE, HexInt
 from esphome.cpp_generator import MockObj, TemplateArgsType
+import esphome.final_validate as fv
 from esphome.types import ConfigType
 
 CODEOWNERS = ["@jesserockz"]
@@ -132,6 +134,24 @@ CONFIG_SCHEMA = cv.All(
 )
 
 
+def _validate_variant(config: ConfigType) -> ConfigType:
+    # ESP-NOW rides the Wi-Fi PHY. Radio-less esp32 variants have no native
+    # ESP-NOW; only the ESP32-P4 has a path, via the esp32_hosted shim that
+    # supplies the esp_now_* symbols. Fail here with a clear message instead of
+    # letting the build reach an "undefined reference to esp_now_*" link error.
+    variant = get_esp32_variant()
+    if wifi.variant_has_wifi(variant):
+        return config
+    if variant != VARIANT_ESP32P4:
+        raise cv.Invalid(f"ESP-NOW is not supported on {variant} (no Wi-Fi radio)")
+    if "esp32_hosted" not in fv.full_config.get():
+        raise cv.Invalid(f"ESP-NOW on {variant} requires the esp32_hosted component")
+    return config
+
+
+FINAL_VALIDATE_SCHEMA = _validate_variant
+
+
 async def _trigger_to_code(config: ConfigType) -> MockObj:
     if address := config.get(CONF_ADDRESS):
         address = address.parts

esphome/components/mdns/__init__.py

@@ -192,6 +192,8 @@ async def to_code(config: ConfigType) -> None:
     if CORE.using_arduino:
         if CORE.is_esp8266:
             cg.add_library("ESP8266mDNS", None)
+            # No MDNS global in the build; mdns_esp8266.cpp owns a guarded MDNSResponder
+            cg.add_build_flag("-DNO_GLOBAL_MDNS")
         elif CORE.is_rp2:
             cg.add_library("LEAmDNS", None)
 

esphome/components/mdns/mdns_esp8266.cpp

@@ -13,8 +13,47 @@
 
 namespace esphome::mdns {
 
+// Main-loop calls into LEAmDNS that send (update() and close(); begin(), addService() and
+// the scheduled restart never reach a send) can yield inside UdpContext::sendTimeout(); a
+// packet arriving then re-enters LEAmDNS from lwIP on the same UdpContext and both sides
+// free the same tx pbufs (#18760). Received packets stay queued during such a call and are
+// processed from the main loop afterwards.
+class GuardedMDNSResponder : public ::esp8266::MDNSImplementation::MDNSResponder {
+ public:
+  void update_guarded() { this->run_guarded_(&GuardedMDNSResponder::update); }
+  void close_guarded() { this->run_guarded_(&GuardedMDNSResponder::close); }
+
+ private:
+  void run_guarded_(bool (GuardedMDNSResponder::*fn)()) {
+    UdpContext *ctx = this->m_pUDPContext;
+    if (ctx == nullptr) {
+      (this->*fn)();
+      return;
+    }
+    // Set every time: a restart replaces the context together with its stock handler. Only
+    // begin() and the scheduled netif callback restart, never update() or close(), so the
+    // context cannot change underneath this call.
+    ctx->onRx([this]() {
+      if (!this->in_loop_call_) {
+        this->_callProcess();
+      }
+    });
+    this->in_loop_call_ = true;
+    (this->*fn)();
+    // close() releases the context; a yield in here queues further packets for this loop too
+    while (this->m_pUDPContext != nullptr && this->m_pUDPContext->next()) {
+      this->_parseMessage();
+    }
+    this->in_loop_call_ = false;
+  }
+
+  volatile bool in_loop_call_{false};
+};
+
+static GuardedMDNSResponder mdns_responder;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
+
 static void register_esp8266(MDNSComponent *, StaticVector<MDNSService, MDNS_SERVICE_COUNT> &services) {
-  MDNS.begin(App.get_name().c_str());
+  mdns_responder.begin(App.get_name().c_str());
 
   for (const auto &service : services) {
     // Strip the leading underscore from the proto and service_type. While it is
@@ -30,10 +69,10 @@ static void register_esp8266(MDNSComponent *, StaticVector<MDNSService, MDNS_SER
       service_type++;
     }
     uint16_t port = service.port.value();
-    MDNS.addService(FPSTR(service_type), FPSTR(proto), port);
+    mdns_responder.addService(FPSTR(service_type), FPSTR(proto), port);
     for (const auto &record : service.txt_records) {
-      MDNS.addServiceTxt(FPSTR(service_type), FPSTR(proto), FPSTR(MDNS_STR_ARG(record.key)),
-                         FPSTR(MDNS_STR_ARG(record.value)));
+      mdns_responder.addServiceTxt(FPSTR(service_type), FPSTR(proto), FPSTR(MDNS_STR_ARG(record.key)),
+                                   FPSTR(MDNS_STR_ARG(record.value)));
     }
   }
 }
@@ -52,7 +91,7 @@ void MDNSComponent::start_polling_window_() {
     if (wifi->is_roaming() || (!wifi->is_connected() && !wifi->is_ap_active()))
       return;
 #endif
-    MDNS.update();
+    mdns_responder.update_guarded();
   });
   this->set_timeout(MDNS_POLL_STOP_ID, MDNS_POLL_WINDOW_MS, [this]() { this->cancel_interval(MDNS_POLL_ID); });
 }
@@ -81,7 +120,7 @@ void MDNSComponent::on_ip_state(const network::IPAddresses &ips, const network::
 #endif
 
 void MDNSComponent::on_shutdown() {
-  MDNS.close();
+  mdns_responder.close_guarded();
   delay(10);
 }
 

esphome/components/noise/__init__.py

@@ -5,7 +5,7 @@ from typing import Any
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.const import CONF_ENCRYPTION, CONF_KEY
-from esphome.core import CORE, ID
+from esphome.core import ID
 from esphome.cpp_generator import MockObj
 from esphome.types import ConfigType
 
@@ -13,11 +13,6 @@ CODEOWNERS = ["@esphome/core"]
 
 noise_ns = cg.esphome_ns.namespace("noise")
 
-# Keep in sync with platformio.ini and esphome/idf_component.yml.
-# LIBSODIUM_VERSION must match the version noise-c pins in its manifests.
-NOISE_C_VERSION = "0.1.21"
-LIBSODIUM_VERSION = "1.10021.4"
-
 CONFIG_SCHEMA = cv.Schema({})
 
 
@@ -93,31 +88,12 @@ def encryption_schema(config: ConfigType | None) -> ConfigType:
 
 async def to_code(config: ConfigType) -> None:
     cg.add_define("USE_NOISE")
-    # Both libraries build themselves as ESP-IDF components, so on ESP32 they
-    # are pulled straight from the component registry instead of going through
-    # ESPHome's PlatformIO-library converter. Deliberately not conditional on
-    # the toolchain: wireguard splits on the same condition, and if the two
-    # disagree one of them converts a second libsodium next to the managed one.
-    #
-    # Not on the Arduino framework though: arduino-esp32 depends on
-    # espressif/libsodium of its own (on IDF < 6.0), so the component manager
-    # would see two managed components whose names match once the namespace is
-    # stripped, and refuse to pick between them.
-    #
-    # libsodium is declared alongside noise-c rather than left to noise-c's own
-    # manifest either way: it lets the library manager see the full set up front
-    # instead of discovering libsodium only after noise-c has downloaded, and it
-    # keeps other components that depend on it (wireguard) from converting a
-    # second copy next to the managed one. The version must match the one
-    # noise-c pins.
-    if CORE.is_esp32 and not CORE.using_arduino:
-        from esphome.components.esp32 import add_idf_component
-
-        add_idf_component(name="esphome/noise-c", ref=NOISE_C_VERSION)
-        add_idf_component(name="esphome/libsodium", ref=LIBSODIUM_VERSION)
-    else:
-        cg.add_library("esphome/noise-c", NOISE_C_VERSION)
-        cg.add_library("esphome/libsodium", LIBSODIUM_VERSION)
+    cg.add_library("esphome/noise-c", "0.1.24")
+    # noise-c depends on libsodium, but declaring it here too lets the
+    # library manager see the full set up front instead of discovering
+    # libsodium only after noise-c has downloaded, so the two can download
+    # in parallel. The version must match noise-c's library.json.
+    cg.add_library("esphome/libsodium", "1.10021.6")
     # Enable optimized memzero/memcmp in libsodium instead of volatile byte loops
     cg.add_build_flag("-DHAVE_WEAK_SYMBOLS=1")
     cg.add_build_flag("-DHAVE_INLINE_ASM=1")

esphome/core/defines.h

@@ -71,6 +71,7 @@
 #define USE_ESP32_HOSTED
 #define USE_ESP32_HOSTED_HTTP_UPDATE
 #define USE_ESP32_IMPROV_STATE_CALLBACK
+#define USE_ESP_NOW_HOSTED
 #define USE_EVENT
 #define USE_FAN
 #define USE_GPIO_BINARY_SENSOR_INTERRUPT

esphome/espidf/clang_tidy.py

@@ -238,17 +238,6 @@ def _parse_lib_deps(platformio_ini: Path, framework: str):
     return libs
 
 
-def _esphome_manifest_deps() -> set[str]:
-    """Names of the managed components declared in ``esphome/idf_component.yml``."""
-    import yaml
-
-    esphome_dir = Path(__file__).resolve().parent.parent
-    manifest = yaml.safe_load(
-        (esphome_dir / "idf_component.yml").read_text(encoding="utf-8")
-    )
-    return set(manifest.get("dependencies") or {})
-
-
 def _convert_pio_libs(
     platformio_ini: Path, framework: str
 ) -> dict[str, dict[str, str]]:
@@ -261,20 +250,12 @@ def _convert_pio_libs(
     The whole library set is resolved as a single batch so a shared transitive
     dependency (e.g. esphome/libsodium pulled by both noise-c and esp_wireguard)
     is deduplicated to one component instead of clashing override_path entries.
-
-    Libraries ESPHome's own manifest already provides as managed components
-    (noise-c, libsodium, ...) are skipped, mirroring what the real esp32 build
-    does -- converting them too would make IDF see the same requirement twice.
-    On Arduino those entries are rule-disabled in the manifest (arduino-esp32
-    brings its own libsodium), so nothing provides them there and they have to
-    go through the converter as before.
     """
     from esphome.espidf.component import generate_idf_components
 
     libraries = _parse_lib_deps(platformio_ini, framework)
-    managed = set() if framework == "arduino" else _esphome_manifest_deps()
     deps: dict[str, dict[str, str]] = {}
-    for component in generate_idf_components(libraries, managed=managed):
+    for component in generate_idf_components(libraries):
         deps[component.get_sanitized_name()] = {"override_path": str(component.path)}
     return deps
 
@@ -292,13 +273,19 @@ def _arduino_excluded_stubs(work_dir: Path) -> dict[str, dict]:
     ethernet) are NOT stubbed -- those are real deps we need, and arduino-esp32
     resolves to the same component rather than conflicting.
     """
+    import yaml
+
     from esphome.components.esp32 import (
         ARDUINO_EXCLUDED_IDF_COMPONENTS,
         _idf_component_dep_name,
         _idf_component_stub_name,
     )
 
-    esphome_deps = _esphome_manifest_deps()
+    esphome_dir = Path(__file__).resolve().parent.parent
+    base_manifest = yaml.safe_load(
+        (esphome_dir / "idf_component.yml").read_text(encoding="utf-8")
+    )
+    esphome_deps = set(base_manifest.get("dependencies") or {})
 
     stubs_dir = work_dir / "component_stubs"
     stubs_dir.mkdir(parents=True, exist_ok=True)

esphome/espidf/component.py

@@ -287,22 +287,12 @@ def _emit_idf_component(component: IDFComponent) -> None:
     )
 
 
-def generate_idf_components(
-    libraries: list[Library], managed: set[str] | None = None
-) -> list[IDFComponent]:
-    """Resolve and convert a batch of PlatformIO libraries to IDF components.
-
-    ``managed`` names the registry components already declared in the project
-    manifest (via ``add_idf_component``). Those are skipped by the converter --
-    a library must not be both converted and managed, or IDF fails component
-    discovery with "Requirement <owner>__<name> and requirement <name> are both
-    added as project_managed_components". Converted components pick the managed
-    one up through ``${ESPHOME_PROJECT_MANAGED_COMPONENTS}`` in their REQUIRES.
-    """
+def generate_idf_components(libraries: list[Library]) -> list[IDFComponent]:
+    """Resolve and convert a batch of PlatformIO libraries to IDF components."""
     backend = LibraryBackend(
         platform=ESP32_PLATFORM,
         framework=_idf_framework(),
         emit=_emit_idf_component,
         cache_key="idf",
     )
-    return convert_libraries(libraries, backend, provided=managed)
+    return convert_libraries(libraries, backend)

esphome/framework_helpers.py

@@ -23,6 +23,7 @@ from esphome.net_retry import (
 )
 
 if TYPE_CHECKING:
+    from filelock import FileLock
     import requests
 
 PathType = str | os.PathLike
@@ -909,6 +910,61 @@ def _part_path(dest: Path) -> Path:
     return dest.with_name(dest.name + ".part")
 
 
+def downloaded_bytes(dest: Path, size: int | None = None) -> int:
+    """Bytes of ``dest`` on disk (its ``.part`` while streaming), capped at ``size``."""
+    done = 0
+    for candidate in (_part_path(dest), dest):
+        try:
+            done = candidate.stat().st_size
+            break
+        except FileNotFoundError:
+            continue
+    return done if size is None else min(done, size)
+
+
+# Short lock-acquire slices so a waiting worker still observes Ctrl-C
+_DOWNLOAD_LOCK_POLL = 1
+
+# Waiting on another process's download; past this the caller leaves the
+# file to its holder (the later sequential install waits on the same lock)
+DOWNLOAD_LOCK_TIMEOUT = 60
+
+
+class DownloadLockUnavailable(OSError):
+    """The lock file cannot be used at all (a lock-less filesystem)."""
+
+
+def wait_for_download_lock(
+    lock: "FileLock",
+    tracker: Callable[[int], None],
+    on_disk: Callable[[], int],
+    name: str,
+) -> None:
+    """Acquire ``lock``, reporting ``on_disk()`` to ``tracker`` each poll so the
+    bar follows the holder's download. Raises filelock's ``Timeout`` once
+    ``DOWNLOAD_LOCK_TIMEOUT`` seconds pass."""
+    from filelock import Timeout
+
+    deadline = time.monotonic() + DOWNLOAD_LOCK_TIMEOUT
+    waiting = False
+    while True:
+        try:
+            lock.acquire(timeout=_DOWNLOAD_LOCK_POLL)
+            return
+        except Timeout:
+            pass
+        except OSError as err:
+            # Distinct from an OSError out of on_disk(), which must not
+            # read as "locks unsupported"
+            raise DownloadLockUnavailable(*err.args) from err
+        if not waiting:
+            waiting = True
+            _LOGGER.info("Waiting for another process downloading %s", name)
+        tracker(on_disk())  # raises when the batch is cancelled
+        if time.monotonic() >= deadline:
+            raise Timeout(lock.lock_file)
+
+
 def discard_partial_download(dest: Path) -> None:
     """Remove ``dest`` and the resume sidecars of an abandoned download."""
     part = _part_path(dest)
@@ -1319,10 +1375,7 @@ def download_from_mirrors(
             )
             # Tick with the bytes already on disk so a combined bar holds
             # steady during the backoff instead of rewinding to zero
-            done = 0
-            if progress is not None:
-                part = _part_path(path_target)
-                done = part.stat().st_size if part.is_file() else 0
+            done = downloaded_bytes(path_target) if progress is not None else 0
             _cancellable_sleep(delay, progress, done)
 
     # 3. Report every attempted URL if all mirrors failed. failures spans

esphome/idf_component.yml

@@ -106,16 +106,3 @@ dependencies:
     version: d44c800a9e876a8394caefc2ce4915dd96dac77b
     rules:
       - if: "$ESPHOME_ARDUINO_COMPONENT == 1"
-  # api. Not on Arduino: arduino-esp32 pulls espressif/libsodium, and IDF
-  # refuses to build two managed components whose names differ only by
-  # namespace. The Arduino envs get noise-c as a PlatformIO library instead.
-  esphome/noise-c:
-    version: 0.1.21
-    rules:
-      - if: "$ESPHOME_ARDUINO_COMPONENT == 0"
-  # Declared even though noise-c depends on it, so that the PlatformIO-library
-  # converter knows to skip the copy esp_wireguard would otherwise pull in.
-  esphome/libsodium:
-    version: 1.10021.4
-    rules:
-      - if: "$ESPHOME_ARDUINO_COMPONENT == 0"

esphome/platformio/library.py

@@ -1102,9 +1102,7 @@ def _prefetch_wave(
 
 
 def convert_libraries(
-    libraries: list[Library],
-    backend: LibraryBackend,
-    provided: set[str] | None = None,
+    libraries: list[Library], backend: LibraryBackend
 ) -> list[ConvertedLibrary]:
     """Resolve and convert a batch of PlatformIO libraries for ``backend``.
 
@@ -1125,24 +1123,14 @@ def convert_libraries(
     ``lib_ignore`` from ``esphome->platformio_options`` excludes libraries by
     short name (part after the ``/``), matched against both the top-level
     libraries and every dependency discovered during the graph walk.
-
-    ``provided`` names libraries the toolchain already supplies by other means
-    (for ESP-IDF: registry-managed components declared via
-    ``add_idf_component``). They are excluded exactly like ``lib_ignore``, so a
-    library is never both converted and managed -- ESP-IDF refuses to build when
-    two components claim the same requirement.
     """
     nodes: dict[str, _LibNode] = {}
 
-    # Libraries the toolchain supplies by other means are excluded exactly like
-    # lib_ignore, so every is_lib_ignored() call site honors both.
-    lib_ignore = lib_ignore_set() | {
-        name.split("/")[-1].lower() for name in provided or ()
-    }
+    lib_ignore = lib_ignore_set()
 
     # The generated build files inside the shared cache bake in the dependency
-    # wiring, which the exclusion set changes; salt the cache path so configs
-    # with different exclusions don't fight over (and constantly rewrite) the
+    # wiring, which lib_ignore changes; salt the cache path so configs with
+    # different lib_ignore values don't fight over (and constantly rewrite) the
     # same converted component files.
     salt = (
         hashlib.sha256(",".join(sorted(lib_ignore)).encode()).hexdigest()[:8]

esphome/platformio/prefetch.py

@@ -33,11 +33,14 @@ import time
 from typing import Any, NamedTuple
 
 from esphome.framework_helpers import (
+    DownloadLockUnavailable,
     content_length,
     discard_partial_download,
+    downloaded_bytes,
     failure_reason,
     resume_fetch_job,
     run_batch_downloads,
+    wait_for_download_lock,
     warn_prefetch_failures,
 )
 from esphome.helpers import get_bool_env, get_usable_cpu_count, rmtree
@@ -61,16 +64,10 @@ _RESOLVE_WORKERS = 8
 # A hung child must not block the build; downloads resume on the next run
 _PREFETCH_TIMEOUT = 20 * 60
 
-# Waiting on another process's URL download; past this, leave it to pio
-_DOWNLOAD_LOCK_TIMEOUT = 60
-
 # Child exit for a handled, already-warned failure; 1 would collide with
 # the interpreter's own import-failure exit
 _EXIT_HANDLED = 3
 
-# Short lock-acquire slices so a waiting worker still observes Ctrl-C
-_URI_LOCK_POLL = 1
-
 # Resolution errored (vs a clean skip); suppresses the warm sentinel
 _RESOLVE_FAILED = object()
 
@@ -462,51 +459,54 @@ def _uri_jobs(
 
 
 def _serialized_fetch_job(
-    dl_path: Path, lock_path: str, body: Any, unlocked_ok: bool = True
+    dl_path: Path,
+    lock_path: str,
+    body: Any,
+    size: int,
+    stream_dest: Path | None = None,
+    unlocked_ok: bool = True,
 ) -> Any:
-    """Wrap ``body`` so the shared destination is single-writer.
-
-    Interleaved writers truncate each other's ``.part`` bytes (see
-    registry.py). The bounded poll observes Ctrl-C via the tracker; a
-    blown deadline is a clean skip (the holder's copy is what the build
-    needs). On a lock-less filesystem a sha256-verified body runs
-    unlocked with one warning; a checksum-less one
-    (``unlocked_ok=False``) is a counted failure instead.
+    """Wrap ``body`` so the shared destination is single-writer (interleaved
+    writers truncate each other's ``.part``, see registry.py). A blown deadline
+    is a clean skip. On a lock-less filesystem a sha256-verified body runs
+    unlocked with one warning; a checksum-less one (``unlocked_ok=False``) fails.
     """
 
+    def on_disk() -> int:
+        # A URL job's holder streams beside the staging path until it
+        # promotes; after that only dl_path is left
+        done = downloaded_bytes(dl_path, size)
+        if not done and stream_dest is not None:
+            done = downloaded_bytes(stream_dest, size)
+        return done
+
     def run(tracker: Any) -> None:
         from filelock import FileLock, Timeout
 
         # fallback_to_soft would leave a stale marker on lock-less
         # filesystems that blocks every later build (see git.py)
         lock = FileLock(lock_path, fallback_to_soft=False)
-        deadline = time.monotonic() + _DOWNLOAD_LOCK_TIMEOUT
-        while True:
-            try:
-                lock.acquire(timeout=_URI_LOCK_POLL)
-                break
-            except Timeout:
-                tracker(0)  # raises when the batch is cancelled
-                if time.monotonic() >= deadline:
-                    # Another process is fetching this same file; its copy
-                    # is what the build needs (a large framework archive
-                    # can hold the lock far longer than this deadline)
-                    _LOGGER.debug("Leaving %s to its current downloader", dl_path.name)
-                    return
-            except OSError as err:
-                if not unlocked_ok:
-                    # A body with no checksum to catch interleaved corruption
-                    raise
-                lock = None
-                _LOGGER.warning(
-                    "Could not lock %s (%s); downloading unlocked",
-                    dl_path.name,
-                    err,
-                )
-                break
+        try:
+            wait_for_download_lock(lock, tracker, on_disk, dl_path.name)
+        except Timeout:
+            # The holder's copy is what the build needs (a large
+            # framework archive can outlast this deadline)
+            _LOGGER.debug("Leaving %s to its current downloader", dl_path.name)
+            return
+        except DownloadLockUnavailable as err:
+            if not unlocked_ok:
+                # A body with no checksum to catch interleaved corruption
+                raise
+            lock = None
+            _LOGGER.warning(
+                "Could not lock %s (%s); downloading unlocked",
+                dl_path.name,
+                err,
+            )
         try:
             if dl_path.is_file():
-                return  # another process finished it while we waited
+                tracker(size)  # another process finished it while we waited
+                return
             body(tracker)
         finally:
             if lock is not None:
@@ -540,6 +540,7 @@ def _registry_fetch_job(
         dl_path,
         f"{dl_path}.esphome.lock",
         resume_fetch_job(url, dl_path, sha256=checksum, size=size),
+        size,
     )
 
     def run(tracker: Any) -> None:
@@ -571,9 +572,9 @@ def _uri_fetch_job(manager: Any, url: str, dl_path: Path, size: int) -> Any:
         tmp.replace(dl_path)
 
     def run(tracker: Any) -> None:
-        _serialized_fetch_job(dl_path, f"{tmp}.lock", promote, unlocked_ok=False)(
-            tracker
-        )
+        _serialized_fetch_job(
+            dl_path, f"{tmp}.lock", promote, size, tmp, unlocked_ok=False
+        )(tracker)
         if dl_path.is_file():
             # Won or lost, the race is over; staging files left behind
             # are dead weight PlatformIO's cache never prunes

esphome/platformio/registry.py

@@ -17,8 +17,10 @@ from esphome.framework_helpers import (
     archive_extract_all,
     download_from_mirrors,
     download_with_resume,
+    downloaded_bytes,
     rmdir,
     run_batch_downloads,
+    wait_for_download_lock,
 )
 from esphome.net_retry import fetch_with_retry, http_request
 
@@ -164,11 +166,17 @@ class _PendingArchive(NamedTuple):
     name: str
     version: str
     dest: Path
+    archive: Path
     url: str
     sha256: str
     size: int
 
 
+def _archive_path(downloads_dir: Path, name: str, version: str) -> Path:
+    """The one archive path the prefetch and the sequential install share."""
+    return downloads_dir / f"{name}-{version}"
+
+
 def _already_installed(dest: Path) -> bool:
     """Whether ``dest`` holds a completed install (extraction marker)."""
     return (dest / ".esphome_extracted").is_file()
@@ -187,18 +195,18 @@ def prefetch_packages(
     lock as ``install_package``: the archive's ``.part`` file is shared, and
     two concurrent writers would truncate each other's bytes.
     """
-    from filelock import FileLock
+    from filelock import FileLock, Timeout
 
     pending: list[_PendingArchive] = []
-    seen: set[str] = set()
+    seen: set[Path] = set()
     for name, version, dest, mirrors in packages:
         if mirrors or (dest / ".esphome_extracted").is_file():
             continue
-        archive_name = f"{name}-{version}"
-        if archive_name in seen:
+        archive = _archive_path(downloads_dir, name, version)
+        if archive in seen:
             # A duplicate entry would race itself between two workers
             continue
-        seen.add(archive_name)
+        seen.add(archive)
         try:
             url, sha256, size = registry_download(name, version)
         except EsphomeError as err:
@@ -207,10 +215,9 @@ def prefetch_packages(
             continue
         if not size:
             continue
-        archive = downloads_dir / archive_name
         if archive.is_file() and archive.stat().st_size == size:
             continue
-        pending.append(_PendingArchive(name, version, dest, url, sha256, size))
+        pending.append(_PendingArchive(name, version, dest, archive, url, sha256, size))
     if len(pending) < 2:
         return
     downloads_dir.mkdir(parents=True, exist_ok=True)
@@ -222,20 +229,36 @@ def prefetch_packages(
 
     def _fetch(entry: _PendingArchive, tracker: Callable[[int], None]) -> None:
         entry.dest.parent.mkdir(parents=True, exist_ok=True)
-        with FileLock(f"{entry.dest}.lock", fallback_to_soft=False):
-            # Marker re-check: a concurrent build may have installed (and
-            # deleted the archive of) this package while we waited;
-            # re-downloading would orphan a fresh copy in downloads_dir
-            # no branch: the thread tracer misses the skip edge; both
-            # arms of _already_installed are pinned directly
-            if not _already_installed(entry.dest):  # pragma: no branch
-                download_with_resume(
-                    entry.url,
-                    downloads_dir / f"{entry.name}-{entry.version}",
-                    sha256=entry.sha256,
-                    size=entry.size,
-                    progress=tracker,
-                )
+
+        def on_disk() -> int:
+            if done := downloaded_bytes(entry.archive, entry.size):
+                return done
+            # The holder deletes the archive once it has installed it
+            return entry.size if _already_installed(entry.dest) else 0
+
+        lock = FileLock(f"{entry.dest}.lock", fallback_to_soft=False)
+        try:
+            wait_for_download_lock(lock, tracker, on_disk, entry.name)
+        except Timeout:
+            # install_package waits on this same lock and verifies the
+            # holder's copy
+            _LOGGER.debug("Leaving %s to its current downloader", entry.name)
+            return
+        try:
+            if _already_installed(entry.dest):
+                # A concurrent build installed it while we waited; a
+                # re-download would orphan a fresh copy in downloads_dir
+                tracker(entry.size)
+                return
+            download_with_resume(
+                entry.url,
+                entry.archive,
+                sha256=entry.sha256,
+                size=entry.size,
+                progress=tracker,
+            )
+        finally:
+            lock.release()
 
     failures = run_batch_downloads(
         "Downloading packages",
@@ -288,7 +311,7 @@ def install_package(
         rmdir(dest, msg=f"Clean up incomplete {name} install")
         # Persistent location so an interrupted download resumes across runs.
         downloads_dir.mkdir(parents=True, exist_ok=True)
-        archive = downloads_dir / f"{name}-{version}"
+        archive = _archive_path(downloads_dir, name, version)
         _LOGGER.info("Downloading %s %s ...", name, version)
         if mirrors:
             _LOGGER.warning(

platformio.ini

@@ -45,6 +45,7 @@ lib_deps_base =
 lib_deps =
     ${common.lib_deps_base}
     https://github.com/dudanov/MideaUART.git#eeea6c3e9b4474f067054592b435be1c4e466815 ; midea
+    esphome/noise-c@0.1.24                 ; noise (api, ota)
     improv/Improv@1.2.7                    ; improv_serial / esp32_improv
     kikuchan98/pngle@1.1.0                 ; online_image
     ; Using the repository directly, otherwise ESP-IDF can't use the library
@@ -76,9 +77,6 @@ lib_compat_mode = strict
 extends = common
 lib_deps =
     ${common.lib_deps}
-    ; api -- on the ESP-IDF framework this comes from the component registry
-    ; instead (see esphome/idf_component.yml), so it is not in [common].
-    esphome/noise-c@0.1.21                                ; api
     SPI                                                   ; spi (Arduino built-in)
     Wire                                                  ; i2c (Arduino built-int)
     heman/AsyncMqttClient-esphome@1.0.0                   ; mqtt
@@ -246,7 +244,7 @@ lib_deps =
     ${common:idf-component-libs.lib_deps}
     ESP32Async/ESPAsyncWebServer@3.9.6    ; web_server_base
     droscy/esp_wireguard@0.4.5            ; wireguard
-    esphome/noise-c@0.1.21                ; noise (api, ota)
+    esphome/noise-c@0.1.24                ; noise (api, ota)
     ESP32Async/AsyncTCP@3.4.5             ; async_tcp
     DNSServer                             ; captive_portal
     heman/AsyncMqttClient-esphome@2.0.0   ; mqtt
@@ -643,7 +641,7 @@ build_unflags =
 extends = common
 platform = platformio/native
 lib_deps =
-    esphome/noise-c@0.1.21  ; used by noise (api, ota)
+    esphome/noise-c@0.1.24  ; used by noise (api, ota)
     lvgl/lvgl@9.5.0         ; lvgl
 build_flags =
     ${common.build_flags}

script/api_protobuf/api_protobuf.py

@@ -131,6 +131,12 @@ def force_str(force: bool) -> str:
     return str(force).lower()
 
 
+def _encode_call(func: str, *args: str, force: bool = False) -> str:
+    """Emit one ProtoEncode call; every helper takes the cursor and returns it advanced."""
+    suffix = "_force" if force else ""
+    return f"pos = ProtoEncode::{func}{suffix}({', '.join(('pos', *args))});"
+
+
 class TypeInfo(ABC):
     """Base class for all type information."""
 
@@ -264,14 +270,16 @@ class TypeInfo(ABC):
     # write_raw_byte(tag) + raw encode instead of the full encode_* method,
     # eliminating the zero-check branch and encode_field_raw indirection.
     # {value} is replaced with the actual field expression.
-    RAW_ENCODE_MAP: dict[str, str] = {
-        "encode_uint32": "ProtoEncode::encode_varint_raw(pos, {value});",
-        "encode_uint64": "ProtoEncode::encode_varint_raw_64(pos, {value});",
-        "encode_sint32": "ProtoEncode::encode_varint_raw_short(pos, encode_zigzag32({value}));",
-        "encode_sint64": "ProtoEncode::encode_varint_raw_64(pos, encode_zigzag64({value}));",
-        "encode_int64": "ProtoEncode::encode_varint_raw_64(pos, static_cast<uint64_t>({value}));",
-        "encode_bool": "ProtoEncode::write_raw_byte(pos, {value} ? 0x01 : 0x00);",
+    RAW_ENCODE_MAP: dict[str, tuple[str, str]] = {
+        "encode_uint32": ("encode_varint_raw", "{value}"),
+        "encode_uint64": ("encode_varint_raw_64", "{value}"),
+        "encode_sint32": ("encode_varint_raw_short", "encode_zigzag32({value})"),
+        "encode_sint64": ("encode_varint_raw_64", "encode_zigzag64({value})"),
+        "encode_int64": ("encode_varint_raw_64", "static_cast<uint64_t>({value})"),
+        "encode_bool": ("write_raw_byte", "{value} ? 0x01 : 0x00"),
     }
+    # Fixed32 value expression for the shared tag+fixed32 writer; None for other wire types
+    fixed32_value_template: str | None = None
 
     def _encode_with_precomputed_tag(self, value_expr: str) -> str | None:
         """Try to emit a precomputed-tag encode for a field.
@@ -288,12 +296,17 @@ class TypeInfo(ABC):
             return None
         max_val = self.max_value
         # Only use RAW_ENCODE_MAP for forced fields or fields with max_value
-        raw_expr = None
+        raw = None
         if self.force or max_val is not None:
-            raw_expr = self.RAW_ENCODE_MAP.get(self.encode_func)
-        if raw_expr is None:
+            raw = self.RAW_ENCODE_MAP.get(self.encode_func)
+        if raw is None:
             return None
-        body = f"ProtoEncode::write_raw_byte(pos, {tag});\n{raw_expr.format(value=value_expr)}"
+        func, arg = raw
+        body = (
+            _encode_call("write_raw_byte", str(tag))
+            + "\n"
+            + _encode_call(func, arg.format(value=value_expr))
+        )
         if self.force:
             return body
         # Non-forced with max_value: inline zero-check + raw encode
@@ -314,23 +327,43 @@ class TypeInfo(ABC):
             return None
         # When max_len < 128, length varint is always 1 byte
         len_encode = (
-            f"ProtoEncode::write_raw_byte(pos, static_cast<uint8_t>({len_expr}));"
+            _encode_call("write_raw_byte", f"static_cast<uint8_t>({len_expr})")
             if max_len is not None and max_len < 128
-            else f"ProtoEncode::encode_varint_raw(pos, {len_expr});"
+            else _encode_call("encode_varint_raw", len_expr)
         )
+        return "\n".join(
+            (
+                _encode_call("write_raw_byte", str(tag)),
+                len_encode,
+                _encode_call("encode_raw", data_expr, len_expr),
+            )
+        )
+
+    def _encode_fixed32_with_precomputed_tag(self, value_expr: str) -> str | None:
+        """Single-byte tag fixed32 write, or None for multi-byte tags."""
+        tag = self.calculate_tag()
+        if tag >= 128:
+            return None
+        if self.force:
+            return _encode_call("write_tag_and_fixed32", str(tag), value_expr)
         return (
-            f"ProtoEncode::write_raw_byte(pos, {tag});\n"
-            f"{len_encode}\n"
-            f"ProtoEncode::encode_raw(pos, {data_expr}, {len_expr});"
+            f"if (uint32_t raw = {value_expr}; raw != 0) [[likely]] {{\n"
+            f"  {_encode_call('write_tag_and_fixed32', str(tag), 'raw')}\n"
+            "}"
         )
 
     @property
     def encode_content(self) -> str:
-        if result := self._encode_with_precomputed_tag(f"this->{self.field_name}"):
+        value = f"this->{self.field_name}"
+        if result := self._encode_with_precomputed_tag(value):
             return result
-        if self.force:
-            return f"ProtoEncode::{self.encode_func}(pos, {self.number}, this->{self.field_name}, true);"
-        return f"ProtoEncode::{self.encode_func}(pos, {self.number}, this->{self.field_name});"
+        if self.fixed32_value_template is not None and (
+            result := self._encode_fixed32_with_precomputed_tag(
+                self.fixed32_value_template.format(value=value)
+            )
+        ):
+            return result
+        return _encode_call(self.encode_func, str(self.number), value, force=self.force)
 
     encode_func = None
 
@@ -635,6 +668,8 @@ class FloatType(FixedSizeTypeMixin, TypeInfo):
     encode_func = "encode_float"
     wire_type = WireType.FIXED32  # Uses wire type 5
 
+    fixed32_value_template = "float_to_raw({value})"
+
     def dump(self, name: str) -> str:
         o = f'snprintf(buffer, sizeof(buffer), "%g", {name});\n'
         o += "out.append(buffer);"
@@ -697,11 +732,11 @@ class UInt64Type(VarintTypeMixin, TypeInfo):
         return self._get_simple_size_calculation(name, force, "uint64")
 
     @property
-    def RAW_ENCODE_MAP(self) -> dict[str, str]:  # noqa: N802
+    def RAW_ENCODE_MAP(self) -> dict[str, tuple[str, str]]:  # noqa: N802
         if self.mac_address:
             return {
                 **TypeInfo.RAW_ENCODE_MAP,
-                "encode_uint64": "ProtoEncode::encode_varint_raw_48bit(pos, {value});",
+                "encode_uint64": ("encode_varint_raw_48bit", "{value}"),
             }
         return TypeInfo.RAW_ENCODE_MAP
 
@@ -769,15 +804,7 @@ class Fixed32Type(FixedSizeTypeMixin, TypeInfo):
         o += "out.append(buffer);"
         return o
 
-    @property
-    def encode_content(self) -> str:
-        tag = self.calculate_tag()
-        if self.force and tag < 128:
-            # Emit combined tag+value write: precomputed tag + direct memcpy
-            return f"ProtoEncode::write_tag_and_fixed32(pos, {tag}, this->{self.field_name});"
-        if self.force:
-            return f"ProtoEncode::{self.encode_func}(pos, {self.number}, this->{self.field_name}, true);"
-        return f"ProtoEncode::{self.encode_func}(pos, {self.number}, this->{self.field_name});"
+    fixed32_value_template = "{value}"
 
     def get_size_calculation(self, name: str, force: bool = False) -> str:
         field_id_size = self.calculate_field_id_size()
@@ -851,9 +878,12 @@ class StringType(TypeInfo):
             f"this->{self.field_name}_ref_.size()",
         ):
             return result
-        if self.force:
-            return f"ProtoEncode::encode_string(pos, {self.number}, this->{self.field_name}_ref_, true);"
-        return f"ProtoEncode::encode_string(pos, {self.number}, this->{self.field_name}_ref_);"
+        return _encode_call(
+            "encode_string",
+            str(self.number),
+            f"this->{self.field_name}_ref_",
+            force=self.force,
+        )
 
     def dump(self, name):
         # If name is 'it', this is a repeated field element - always use string
@@ -951,7 +981,9 @@ class MessageType(TypeInfo):
     @property
     def encode_content(self) -> str:
         # Sub-message encoding needs buffer for backpatch/sync
-        return f"ProtoEncode::{self.encode_func}(pos, buffer, {self.number}, this->{self.field_name});"
+        return _encode_call(
+            self.encode_func, "buffer", str(self.number), f"this->{self.field_name}"
+        )
 
     @property
     def decode_length(self) -> str:
@@ -1058,9 +1090,13 @@ class BytesType(TypeInfo):
             f"this->{self.field_name}_ptr_", f"this->{self.field_name}_len_"
         ):
             return result
-        if self.force:
-            return f"ProtoEncode::encode_bytes(pos, {self.number}, this->{self.field_name}_ptr_, this->{self.field_name}_len_, true);"
-        return f"ProtoEncode::encode_bytes(pos, {self.number}, this->{self.field_name}_ptr_, this->{self.field_name}_len_);"
+        return _encode_call(
+            "encode_bytes",
+            str(self.number),
+            f"this->{self.field_name}_ptr_",
+            f"this->{self.field_name}_len_",
+            force=self.force,
+        )
 
     def dump(self, name: str) -> str:
         ptr_dump = f"format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_)"
@@ -1170,9 +1206,13 @@ class PointerToBytesBufferType(PointerToBufferTypeBase):
             f"this->{self.field_name}", f"this->{self.field_name}_len"
         ):
             return result
-        if self.force:
-            return f"ProtoEncode::encode_bytes(pos, {self.number}, this->{self.field_name}, this->{self.field_name}_len, true);"
-        return f"ProtoEncode::encode_bytes(pos, {self.number}, this->{self.field_name}, this->{self.field_name}_len);"
+        return _encode_call(
+            "encode_bytes",
+            str(self.number),
+            f"this->{self.field_name}",
+            f"this->{self.field_name}_len",
+            force=self.force,
+        )
 
     @property
     def decode_length_content(self) -> str | None:
@@ -1224,16 +1264,19 @@ class PointerToStringBufferType(PointerToBufferTypeBase):
         if max_len is not None and max_len < 128 and self.force:
             tag = self.calculate_tag()
             if tag < 128:
-                return f"ProtoEncode::encode_short_string_force(pos, {tag}, this->{self.field_name});"
+                return _encode_call(
+                    "encode_short_string_force", str(tag), f"this->{self.field_name}"
+                )
         if result := self._encode_bytes_with_precomputed_tag(
             f"this->{self.field_name}.c_str()",
             f"this->{self.field_name}.size()",
         ):
             return result
-        if self.force:
-            return f"ProtoEncode::encode_string(pos, {self.number}, this->{self.field_name}, true);"
-        return (
-            f"ProtoEncode::encode_string(pos, {self.number}, this->{self.field_name});"
+        return _encode_call(
+            "encode_string",
+            str(self.number),
+            f"this->{self.field_name}",
+            force=self.force,
         )
 
     @property
@@ -1421,9 +1464,13 @@ class FixedArrayBytesType(TypeInfo):
             f"this->{self.field_name}", f"this->{self.field_name}_len", max_len=max_len
         ):
             return result
-        if self.force:
-            return f"ProtoEncode::encode_bytes(pos, {self.number}, this->{self.field_name}, this->{self.field_name}_len, true);"
-        return f"ProtoEncode::encode_bytes(pos, {self.number}, this->{self.field_name}, this->{self.field_name}_len);"
+        return _encode_call(
+            "encode_bytes",
+            str(self.number),
+            f"this->{self.field_name}",
+            f"this->{self.field_name}_len",
+            force=self.force,
+        )
 
     def dump(self, name: str) -> str:
         return f"out.append(format_hex_pretty({name}, {name}_len));"
@@ -1520,9 +1567,9 @@ class EnumType(VarintTypeMixin, TypeInfo):
     @property
     def encode_content(self) -> str:
         value_expr = f"static_cast<uint32_t>(this->{self.field_name})"
-        if self.force:
-            return f"ProtoEncode::{self.encode_func}(pos, {self.number}, {value_expr}, true);"
-        return f"ProtoEncode::{self.encode_func}(pos, {self.number}, {value_expr});"
+        return _encode_call(
+            self.encode_func, str(self.number), value_expr, force=self.force
+        )
 
     def dump(self, name: str) -> str:
         return f"out.append_p(proto_enum_to_string<{self.cpp_type}>({name}));"
@@ -1701,9 +1748,9 @@ def _generate_inline_encode_block(
 
     lines = []
     lines.append(f"auto &sub_msg = {element};")
-    lines.append(f"ProtoEncode::write_raw_byte(pos, {tag});")
+    lines.append(_encode_call("write_raw_byte", str(tag)))
     lines.append("uint8_t *len_pos = pos;")
-    lines.append("ProtoEncode::reserve_byte(pos);")
+    lines.append(_encode_call("reserve_byte"))
 
     # Generate inline field encoding for each sub-message field
     for field in sub_desc.field:
@@ -1775,17 +1822,22 @@ class FixedArrayRepeatedType(TypeInfo):
     def _encode_element(self, element: str) -> str:
         """Helper to generate encode statement for a single element."""
         if isinstance(self._ti, EnumType):
-            return f"ProtoEncode::{self._ti.encode_func}(pos, {self.number}, static_cast<uint32_t>({element}), true);"
+            return _encode_call(
+                self._ti.encode_func,
+                str(self.number),
+                f"static_cast<uint32_t>({element})",
+                force=True,
+            )
         # Repeated message elements use encode_sub_message (force=true is default)
         if isinstance(self._ti, MessageType):
             if _is_inline_encode(self._ti.cpp_type):
                 return _generate_inline_encode_block(
                     self.number, self._ti.cpp_type, element
                 )
-            return f"ProtoEncode::encode_sub_message(pos, buffer, {self.number}, {element});"
-        return (
-            f"ProtoEncode::{self._ti.encode_func}(pos, {self.number}, {element}, true);"
-        )
+            return _encode_call(
+                "encode_sub_message", "buffer", str(self.number), element
+            )
+        return _encode_call(self._ti.encode_func, str(self.number), element, force=True)
 
     @property
     def cpp_type(self) -> str:
@@ -2137,13 +2189,18 @@ class RepeatedTypeInfo(TypeInfo):
     def _encode_element_call(self, element: str) -> str:
         """Helper to generate encode call for a single element."""
         if isinstance(self._ti, EnumType):
-            return f"ProtoEncode::{self._ti.encode_func}(pos, {self.number}, static_cast<uint32_t>({element}), true);"
+            return _encode_call(
+                self._ti.encode_func,
+                str(self.number),
+                f"static_cast<uint32_t>({element})",
+                force=True,
+            )
         # Repeated message elements use encode_sub_message (force=true is default)
         if isinstance(self._ti, MessageType):
-            return f"ProtoEncode::encode_sub_message(pos, buffer, {self.number}, {element});"
-        return (
-            f"ProtoEncode::{self._ti.encode_func}(pos, {self.number}, {element}, true);"
-        )
+            return _encode_call(
+                "encode_sub_message", "buffer", str(self.number), element
+            )
+        return _encode_call(self._ti.encode_func, str(self.number), element, force=True)
 
     @property
     def encode_content(self) -> str:
@@ -2152,7 +2209,7 @@ class RepeatedTypeInfo(TypeInfo):
             # Special handling for const char* elements (when container_no_template contains "const char")
             if "const char" in self._container_no_template:
                 o = f"for (const char *it : *this->{self.field_name}) {{\n"
-                o += f"  ProtoEncode::{self._ti.encode_func}(pos, {self.number}, it, strlen(it), true);\n"
+                o += f"  {_encode_call(self._ti.encode_func, str(self.number), 'it', 'strlen(it)', force=True)}\n"
             else:
                 o = f"for (const auto &it : *this->{self.field_name}) {{\n"
                 o += f"  {self._encode_element_call('it')}\n"

script/ci-custom.py

@@ -294,6 +294,9 @@ def highlight(s):
         "esphome/components/socket/headers.h",
         "esphome/core/defines.h",
         "esphome/components/http_request/httplib.h",
+        # Shared C wire header (byte-identical with the co-processor firmware);
+        # these are protocol constants and constexpr is C++-only.
+        "esphome/components/esp32_hosted/esp_now_hosted_rpc.h",
     ],
 )
 def lint_no_defines(fname, match):
@@ -816,6 +819,10 @@ def lint_relative_py_import(fname: Path, line, col, content):
         "esphome/components/host/helpers.cpp",
         "esphome/components/zephyr/helpers.cpp",
         "esphome/components/http_request/httplib.h",
+        # Global extern "C" esp_now_* linker symbols + shared C wire header;
+        # neither can live in a C++ namespace.
+        "esphome/components/esp32_hosted/esp_now_hosted.cpp",
+        "esphome/components/esp32_hosted/esp_now_hosted_rpc.h",
     ],
 )
 def lint_namespace(fname: Path, content: str) -> str | None:
@@ -841,7 +848,15 @@ def lint_esphome_h(fname, line, col, content):
     )
 
 
-@lint_content_check(include=["*.h"], exclude=["esphome/core/entity_types.h"])
+@lint_content_check(
+    include=["*.h"],
+    exclude=[
+        "esphome/core/entity_types.h",
+        # Shared C wire header; uses a classic #ifndef guard for portability
+        # across the co-processor firmware repo it stays byte-identical with.
+        "esphome/components/esp32_hosted/esp_now_hosted_rpc.h",
+    ],
+)
 def lint_pragma_once(fname, content):
     if "#pragma once" not in content:
         return (

tests/components/api/test_proto_mac_varint.cpp

@@ -59,7 +59,7 @@ static void verify_mac(uint64_t mac, size_t expected_bytes) {
 #ifdef ESPHOME_DEBUG_API
   uint8_t *proto_debug_end_ = api_buf.data() + api_buf.size();
 #endif
-  ProtoEncode::encode_varint_raw_48bit(pos PROTO_ENCODE_DEBUG_ARG, mac);
+  pos = ProtoEncode::encode_varint_raw_48bit(pos PROTO_ENCODE_DEBUG_ARG, mac);
   size_t new_len = pos - api_buf.data();
 
   EXPECT_EQ(new_len, expected_bytes) << "mac=0x" << std::hex << mac << std::dec;

tests/components/esp32_hosted/test-espnow.esp32-p4-idf.yaml

@@ -0,0 +1,5 @@
+# Exercises the ESP-NOW-over-hosted shim: on the ESP32-P4 host, esp32_hosted
+# supplies the esp_now_* symbols that the espnow component links against.
+packages:
+  esp32_hosted: !include common.yaml
+  espnow: !include ../espnow/common.yaml

tests/integration/fixtures/api_encode_boundaries.yaml

@@ -0,0 +1,58 @@
+esphome:
+  name: api-encode-boundaries-test
+  # Top-level area fills DeviceInfoResponse.suggested_area (field 16, a two-byte tag)
+  area:
+    id: kitchen_area
+    name: Kitchen
+  on_boot:
+    - sensor.template.publish:
+        id: zero_then_value
+        state: 0.0
+
+host:
+api:
+logger:
+  level: DEBUG
+
+sensor:
+  - platform: template
+    name: "Zero Then Value"
+    id: zero_then_value
+    # Negative int32 takes the ten byte varint path
+    accuracy_decimals: -2
+    update_interval: never
+
+text_sensor:
+  - platform: template
+    name: "Long Text"
+    id: long_text
+    update_interval: never
+
+number:
+  - platform: template
+    name: "Negative Number"
+    optimistic: true
+    min_value: -1000
+    max_value: 1000
+    step: 0.5
+    initial_value: -123.5
+
+select:
+  - platform: template
+    name: "Long Option Select"
+    optimistic: true
+    options:
+      - short
+      - "option-with-a-name-long-enough-that-its-length-prefix-needs-two-varint-bytes-when-the-list-entities-response-is-encoded-xxxxxxxxxx"
+    initial_option: short
+
+button:
+  - platform: template
+    name: "Publish Values"
+    on_press:
+      - sensor.template.publish:
+          id: zero_then_value
+          state: 12.5
+      - text_sensor.template.publish:
+          id: long_text
+          state: !lambda return std::string(200, 'y');

tests/integration/state_utils.py

@@ -57,6 +57,43 @@ async def wait_for_state(
     return await asyncio.wait_for(future, timeout=timeout)
 
 
+class StateWaiter:
+    """Route one state subscription to any number of predicate waits."""
+
+    def __init__(self) -> None:
+        self._waiters: list[
+            tuple[Callable[[EntityState], bool], asyncio.Future[EntityState]]
+        ] = []
+
+    def on_state(self, state: EntityState) -> None:
+        for predicate, future in self._waiters:
+            if future.done():
+                continue
+            try:
+                matched = predicate(state)
+            except Exception as exc:  # noqa: BLE001  the wait re-raises it, the callback must not die
+                future.set_exception(exc)
+                continue
+            if matched:
+                future.set_result(state)
+
+    async def expect(
+        self, predicate: Callable[[EntityState], bool], timeout: float = 5.0
+    ) -> EntityState:
+        """Wait for the next state matching ``predicate``; states seen before this call do not count."""
+        entry = (predicate, asyncio.get_running_loop().create_future())
+        self._waiters.append(entry)
+        try:
+            async with asyncio.timeout(timeout):
+                return await entry[1]
+        except TimeoutError:
+            raise TimeoutError(
+                f"no state matched {predicate} within {timeout}s"
+            ) from None
+        finally:
+            self._waiters.remove(entry)
+
+
 def find_entity[T: EntityInfo](
     entities: list[EntityInfo],
     object_id_substring: str,

tests/integration/test_api_encode_boundaries.py

@@ -0,0 +1,76 @@
+"""Encode paths at their branch boundaries: zero skipped float, fixed32 state, negative int32,
+length prefixes of two varint bytes and two byte field tags."""
+
+from __future__ import annotations
+
+import asyncio
+
+from aioesphomeapi import (
+    NumberState,
+    SelectInfo,
+    SensorInfo,
+    SensorState,
+    TextSensorState,
+)
+import pytest
+
+from .state_utils import InitialStateHelper, StateWaiter, require_entity
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+LONG_OPTION = (
+    "option-with-a-name-long-enough-that-its-length-prefix-needs-two-varint-bytes-"
+    "when-the-list-entities-response-is-encoded-xxxxxxxxxx"
+)
+
+
+@pytest.mark.asyncio
+async def test_api_encode_boundaries(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    async with run_compiled(yaml_config), api_client_connected() as client:
+        device_info, (entities, _) = await asyncio.gather(
+            client.device_info(), client.list_entities_services()
+        )
+        assert device_info.suggested_area == "Kitchen"
+
+        sensor = require_entity(entities, "zero_then_value", SensorInfo)
+        assert sensor.accuracy_decimals == -2
+        select = require_entity(entities, "long_option_select", SelectInfo)
+        assert len(LONG_OPTION) >= 128
+        assert select.options == ["short", LONG_OPTION]
+        text = require_entity(entities, "long_text")
+        number = require_entity(entities, "negative_number")
+        button = require_entity(entities, "publish_values")
+
+        initial = InitialStateHelper(entities)
+        waiter = StateWaiter()
+        client.subscribe_states(initial.on_state_wrapper(waiter.on_state))
+        await initial.wait_for_initial_states()
+
+        # A float of exactly zero is skipped on the wire and must still read as 0.0, not missing
+        first = initial.initial_states[sensor.key]
+        assert isinstance(first, SensorState)
+        assert first.state == 0.0 and not first.missing_state
+        first_number = initial.initial_states[number.key]
+        assert isinstance(first_number, NumberState)
+        assert first_number.state == -123.5
+
+        client.button_command(button.key)
+        await asyncio.gather(
+            waiter.expect(
+                lambda s: (
+                    isinstance(s, SensorState)
+                    and s.key == sensor.key
+                    and s.state == 12.5
+                )
+            ),
+            waiter.expect(
+                lambda s: (
+                    isinstance(s, TextSensorState)
+                    and s.key == text.key
+                    and s.state == "y" * 200
+                )
+            ),
+        )

tests/script/test_platformio_install_deps.py

@@ -35,8 +35,8 @@ def _load_script():
 def test_spec_key_collapses_destinations() -> None:
     """Two specs delivering one package share a directory and one key."""
     mod = _load_script()
-    assert mod.spec_key("esphome/noise-c @ 0.1.21") == "noise-c"
-    assert mod.spec_key("esphome/noise-c@0.1.21") == "noise-c"
+    assert mod.spec_key("esphome/noise-c @ 0.1.24") == "noise-c"
+    assert mod.spec_key("esphome/noise-c@0.1.24") == "noise-c"
     assert mod.spec_key("ESP32Async/AsyncTCP @ ^3.4.10") == mod.spec_key(
         "esp32async/asynctcp @ 3.5.0"
     )
@@ -54,23 +54,23 @@ def test_parse_specs_and_cli_args(tmp_path: Path) -> None:
         "[env:a]\n"
         "platform = fake/platform@1\n"
         "lib_deps =\n"
-        "    esphome/noise-c @ 0.1.21\n"
+        "    esphome/noise-c @ 0.1.24\n"
         "    ${common.lib_deps}\n"
         "    internal_lib\n"
         "[env:b]\n"
         "lib_deps =\n"
-        "    esphome/noise-c @ 0.1.21\n"
+        "    esphome/noise-c @ 0.1.24\n"
     )
     mod = _load_script()
     args = Namespace(libraries=True, platforms=True, tools=False)
     libs, platforms, tools = mod.parse_specs(str(ini), args)
     # exact-string duplicates collapse; distinct version pins survive
-    assert libs == ["esphome/noise-c @ 0.1.21"]
+    assert libs == ["esphome/noise-c @ 0.1.24"]
     assert platforms == ["fake/platform@1"]
     assert tools == []
     assert mod.build_cli_args(libs, platforms, tools) == [
         "-l",
-        "esphome/noise-c @ 0.1.21",
+        "esphome/noise-c @ 0.1.24",
         "-p",
         "fake/platform@1",
     ]
@@ -162,13 +162,13 @@ def test_parallel_install_behavior(tmp_path: Path) -> None:
     mod.parallel_install(
         cls,
         [
-            "esphome/noise-c @ 0.1.21",
-            "esphome/noise-c @ 0.1.21",
+            "esphome/noise-c @ 0.1.24",
+            "esphome/noise-c @ 0.1.24",
             "esphome/already @ 1.0",
             "https://x/framework.tar.xz",
         ],
     )
-    assert cls.calls == ["esphome/noise-c @ 0.1.21"]
+    assert cls.calls == ["esphome/noise-c @ 0.1.24"]
     assert cls.lock_events == ["lock", "unlock"]
 
 
@@ -205,7 +205,7 @@ def test_parallel_install_runs_dependency_waves(tmp_path: Path) -> None:
     mod = _load_script()
     cls = _reset_fake(str(tmp_path))
     cls.deps = {
-        "esphome/noise-c @ 0.1.21": [
+        "esphome/noise-c @ 0.1.24": [
             {"owner": "esphome", "name": "libsodium", "version": "^1.0"},
             {"name": "SPI"},
         ],
@@ -213,12 +213,12 @@ def test_parallel_install_runs_dependency_waves(tmp_path: Path) -> None:
             {"owner": "esphome", "name": "libsodium", "version": "^1.0"},
         ],
     }
-    mod.parallel_install(cls, ["esphome/noise-c @ 0.1.21", "esphome/wg @ 1.0"])
+    mod.parallel_install(cls, ["esphome/noise-c @ 0.1.24", "esphome/wg @ 1.0"])
     assert len(cls.calls) == 3  # the shared dep installs exactly once
     assert {mod.spec_key(c) for c in cls.calls} == {"noise-c", "wg", "libsodium"}
     # Wave-1 strings carry no compatibility; the dependency wave does
     compats = dict(cls.compat_calls)
-    assert compats["esphome/noise-c @ 0.1.21"] is None
+    assert compats["esphome/noise-c @ 0.1.24"] is None
     dep_compat = next(v for k, v in cls.compat_calls if "libsodium" in k)
     assert dep_compat is not None  # mirrors pio's install_dependency
 
@@ -229,11 +229,11 @@ def test_dependency_wave_excludes_url_specs(tmp_path: Path) -> None:
     mod = _load_script()
     cls = _reset_fake(str(tmp_path))
     cls.deps = {
-        "esphome/noise-c @ 0.1.21": [
+        "esphome/noise-c @ 0.1.24": [
             {"name": "vendored", "version": "https://github.com/x/y.git"},
         ],
     }
-    mod.parallel_install(cls, ["esphome/noise-c @ 0.1.21"])
+    mod.parallel_install(cls, ["esphome/noise-c @ 0.1.24"])
     assert {mod.spec_key(c) for c in cls.calls} == {"noise-c"}
 
 
@@ -348,13 +348,13 @@ def test_warm_store_still_walks_dependencies(tmp_path: Path) -> None:
     """Already-installed top-level packages still feed the dependency
     wave; a warm store can be missing a transitive dep."""
     mod = _load_script()
-    cls = _reset_fake(str(tmp_path), installed={"esphome/noise-c @ 0.1.21"})
+    cls = _reset_fake(str(tmp_path), installed={"esphome/noise-c @ 0.1.24"})
     cls.deps = {
-        "esphome/noise-c @ 0.1.21": [
+        "esphome/noise-c @ 0.1.24": [
             {"owner": "esphome", "name": "libsodium", "version": "^1.0"},
         ],
     }
-    mod.parallel_install(cls, ["esphome/noise-c @ 0.1.21"])
+    mod.parallel_install(cls, ["esphome/noise-c @ 0.1.24"])
     assert [mod.spec_key(c) for c in cls.calls] == ["libsodium"]
 
 

tests/unit_tests/components/api/test_api_proto.py

@@ -380,3 +380,13 @@ def test_api_version_minor_is_at_least_15() -> None:
         "clients to see api_version >= 1.15 in HelloResponse before they will "
         "ever request it."
     )
+
+
+def test_generated_encode_calls_keep_the_cursor() -> None:
+    """No generated ProtoEncode call may drop the returned cursor."""
+    dropped = [
+        line
+        for line in CPP_TEXT.splitlines()
+        if line.lstrip().startswith("ProtoEncode::")
+    ]
+    assert not dropped, dropped[:5]

tests/unit_tests/components/api/test_api_protobuf_generator.py

@@ -15,9 +15,11 @@ import pytest
 
 sys.path.insert(0, str(Path(__file__).parents[4] / "script" / "api_protobuf"))
 
+import aioesphomeapi.api_options_pb2 as pb  # noqa: E402
 from api_protobuf import (  # noqa: E402
     MAX_MESSAGE_ID,
     _make_ifdef_line,
+    create_field_type_info,
     get_varint64_ifdef,
     validate_message_id,
 )
@@ -43,7 +45,14 @@ UINT64 = descriptor_pb2.FieldDescriptorProto.TYPE_UINT64
 INT64 = descriptor_pb2.FieldDescriptorProto.TYPE_INT64
 SINT64 = descriptor_pb2.FieldDescriptorProto.TYPE_SINT64
 UINT32 = descriptor_pb2.FieldDescriptorProto.TYPE_UINT32
+INT32 = descriptor_pb2.FieldDescriptorProto.TYPE_INT32
+SINT32 = descriptor_pb2.FieldDescriptorProto.TYPE_SINT32
 FIXED64 = descriptor_pb2.FieldDescriptorProto.TYPE_FIXED64
+FIXED32 = descriptor_pb2.FieldDescriptorProto.TYPE_FIXED32
+FLOAT = descriptor_pb2.FieldDescriptorProto.TYPE_FLOAT
+BOOL = descriptor_pb2.FieldDescriptorProto.TYPE_BOOL
+STRING = descriptor_pb2.FieldDescriptorProto.TYPE_STRING
+BYTES = descriptor_pb2.FieldDescriptorProto.TYPE_BYTES
 
 
 def test_no_varint64_fields() -> None:
@@ -107,3 +116,69 @@ def test_message_id_at_maximum_is_accepted() -> None:
 def test_message_id_above_maximum_is_rejected() -> None:
     with pytest.raises(ValueError, match="exceeds the plaintext"):
         validate_message_id(MAX_MESSAGE_ID + 1, "TooBigMessage")
+
+
+def _field(
+    field_type: int, number: int = 1, *, force: bool = False, repeated: bool = False
+) -> descriptor_pb2.FieldDescriptorProto:
+    field = descriptor_pb2.FieldDescriptorProto(
+        name="value", number=number, type=field_type
+    )
+    if repeated:
+        field.label = descriptor_pb2.FieldDescriptorProto.LABEL_REPEATED
+    if force:
+        field.options.Extensions[pb.force] = True
+    return field
+
+
+def _encode_field(
+    field_type: int, number: int = 1, force: bool = False, repeated: bool = False
+) -> str:
+    """Return the encode statement the generator emits for one encode-only field."""
+    field = _field(field_type, number, force=force, repeated=repeated)
+    return create_field_type_info(
+        field, needs_decode=False, needs_encode=True
+    ).encode_content
+
+
+SCALAR_TYPES = [
+    BOOL,
+    UINT32,
+    INT32,
+    UINT64,
+    INT64,
+    SINT32,
+    FLOAT,
+    FIXED32,
+    STRING,
+    BYTES,
+]
+
+
+@pytest.mark.parametrize("field_type", SCALAR_TYPES)
+def test_forced_fields_use_the_force_overload_or_raw_writes(field_type: int) -> None:
+    content = _encode_field(field_type, force=True)
+    assert (
+        "_force(" in content
+        or "write_raw_byte(" in content
+        or "write_tag_and_fixed32(" in content
+    ), content
+
+
+@pytest.mark.parametrize("field_type", [FLOAT, FIXED32])
+def test_single_byte_tag_fixed32_shares_the_outlined_writer(field_type: int) -> None:
+    unconditional = _encode_field(field_type, force=True)
+    assert unconditional.count("write_tag_and_fixed32(pos, 13,") == 1, unconditional
+    guarded = _encode_field(field_type, force=False)
+    assert guarded.startswith("if ("), guarded
+    assert "[[likely]]" in guarded
+    assert "write_tag_and_fixed32(pos, 13," in guarded
+
+
+@pytest.mark.parametrize("field_type", [FLOAT, FIXED32])
+def test_multi_byte_tag_fixed32_falls_back_to_the_generic_helper(
+    field_type: int,
+) -> None:
+    content = _encode_field(field_type, number=16)
+    assert "write_tag_and_fixed32" not in content, content
+    assert content.startswith("pos = ProtoEncode::encode_"), content

tests/unit_tests/components/noise/test_noise_to_code.py

@@ -1,131 +0,0 @@
-"""Tests for the noise-c/libsodium library wiring in the noise component.
-
-On ESP32 (but not the Arduino framework) both libraries build themselves as
-native ESP-IDF managed components, so they are declared via add_idf_component()
-instead of going through ESPHome's PlatformIO-library converter, on either
-toolchain. Elsewhere they still go through that converter via cg.add_library():
-on the Arduino framework because arduino-esp32 depends on espressif/libsodium
-of its own, and off ESP32 because there are no IDF components at all. This
-drives the real to_code() coroutine so every branch of that decision is
-exercised end to end, not just mocked.
-"""
-
-from __future__ import annotations
-
-import asyncio
-
-import pytest
-
-import esphome.codegen as cg
-from esphome.components import esp32, noise
-from esphome.const import (
-    KEY_CORE,
-    KEY_TARGET_FRAMEWORK,
-    KEY_TARGET_PLATFORM,
-    Framework,
-    Platform,
-    Toolchain,
-)
-from esphome.core import CORE
-
-
-def _setup_core(platform: Platform, framework: Framework, toolchain: Toolchain) -> None:
-    CORE.reset()
-    CORE.toolchain = toolchain
-    CORE.data[KEY_CORE] = {
-        KEY_TARGET_PLATFORM: str(platform),
-        KEY_TARGET_FRAMEWORK: str(framework),
-    }
-    if platform == Platform.ESP32:
-        CORE.data[esp32.KEY_ESP32] = {esp32.KEY_VARIANT: "ESP32"}
-
-
-def _record_calls(
-    monkeypatch: pytest.MonkeyPatch,
-) -> tuple[list[dict], list[tuple]]:
-    """Capture both wiring paths so each test can assert one ran and one did not."""
-    idf_calls: list[dict] = []
-    lib_calls: list[tuple] = []
-    monkeypatch.setattr(
-        esp32, "add_idf_component", lambda **kwargs: idf_calls.append(kwargs)
-    )
-    monkeypatch.setattr(
-        cg,
-        "add_library",
-        lambda name, version, repository=None: lib_calls.append((name, version)),
-    )
-    return idf_calls, lib_calls
-
-
-@pytest.mark.parametrize("toolchain", [Toolchain.ESP_IDF, Toolchain.PLATFORMIO])
-def test_to_code_esp32_idf_uses_managed_idf_components(
-    toolchain: Toolchain,
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """On ESP32 + ESP-IDF both libraries are declared as managed IDF components
-    rather than converted PlatformIO libraries. The choice is deliberately the
-    same on either toolchain, because wireguard splits on the same condition."""
-    _setup_core(Platform.ESP32, Framework.ESP_IDF, toolchain)
-    idf_calls, lib_calls = _record_calls(monkeypatch)
-
-    asyncio.run(noise.to_code({}))
-
-    assert idf_calls == [
-        {"name": "esphome/noise-c", "ref": noise.NOISE_C_VERSION},
-        {"name": "esphome/libsodium", "ref": noise.LIBSODIUM_VERSION},
-    ]
-    assert lib_calls == []
-
-
-def test_to_code_esp32_arduino_uses_add_library(
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """On the Arduino framework arduino-esp32 depends on espressif/libsodium of
-    its own, so declaring esphome/libsodium as a managed component too would
-    leave the component manager unable to pick between them."""
-    _setup_core(Platform.ESP32, Framework.ARDUINO, Toolchain.ESP_IDF)
-    idf_calls, lib_calls = _record_calls(monkeypatch)
-
-    asyncio.run(noise.to_code({}))
-
-    assert lib_calls == [
-        ("esphome/noise-c", noise.NOISE_C_VERSION),
-        ("esphome/libsodium", noise.LIBSODIUM_VERSION),
-    ]
-    assert idf_calls == []
-
-
-def test_to_code_non_esp32_uses_add_library(
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """Off ESP32 entirely (e.g. host) there are no IDF components at all."""
-    _setup_core(Platform.HOST, Framework.NATIVE, Toolchain.PLATFORMIO)
-    idf_calls, lib_calls = _record_calls(monkeypatch)
-
-    asyncio.run(noise.to_code({}))
-
-    assert lib_calls == [
-        ("esphome/noise-c", noise.NOISE_C_VERSION),
-        ("esphome/libsodium", noise.LIBSODIUM_VERSION),
-    ]
-    assert idf_calls == []
-
-
-def test_versions_match_the_repo_manifests() -> None:
-    """The pins are duplicated in platformio.ini and esphome/idf_component.yml;
-    a bump that misses one would ship two different libsodium versions."""
-    from pathlib import Path
-
-    import yaml
-
-    repo_root = Path(__file__).resolve().parents[4]
-    manifest = yaml.safe_load(
-        (repo_root / "esphome" / "idf_component.yml").read_text(encoding="utf-8")
-    )
-    deps = manifest["dependencies"]
-
-    assert deps["esphome/noise-c"]["version"] == noise.NOISE_C_VERSION
-    assert deps["esphome/libsodium"]["version"] == noise.LIBSODIUM_VERSION
-    assert f"esphome/noise-c@{noise.NOISE_C_VERSION}" in (
-        repo_root / "platformio.ini"
-    ).read_text(encoding="utf-8")

tests/unit_tests/components/test_esp32_write_idf_component_yml.py

@@ -1,107 +0,0 @@
-"""Tests for esp32's _write_idf_component_yml() managed-component wiring.
-
-A library that is already declared as a managed IDF component (via
-add_idf_component(), e.g. api's noise-c/libsodium) must not also be converted
-from a PlatformIO library, or ESP-IDF sees the same requirement declared by
-two components and refuses to build. _write_idf_component_yml() passes the
-set of already-managed component names to generate_idf_components() so the
-converter excludes them.
-"""
-
-from __future__ import annotations
-
-from pathlib import Path
-from unittest.mock import MagicMock
-
-import pytest
-
-from esphome.components import esp32
-from esphome.const import (
-    KEY_CORE,
-    KEY_TARGET_FRAMEWORK,
-    KEY_TARGET_PLATFORM,
-    Framework,
-    Platform,
-    Toolchain,
-)
-from esphome.core import CORE
-
-
-def _setup_core(tmp_path: Path) -> None:
-    CORE.reset()
-    CORE.name = "testdevice"
-    CORE.build_path = tmp_path
-    CORE.toolchain = Toolchain.ESP_IDF
-    CORE.data[KEY_CORE] = {
-        KEY_TARGET_PLATFORM: str(Platform.ESP32),
-        KEY_TARGET_FRAMEWORK: str(Framework.ESP_IDF),
-    }
-
-
-def test_write_idf_component_yml_passes_managed_components(
-    tmp_path: Path,
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """The names already registered via add_idf_component (e.g. noise-c from
-    api's encryption config) are passed through as ``managed`` so the
-    PlatformIO-library converter skips them."""
-    _setup_core(tmp_path)
-    CORE.data[esp32.KEY_ESP32] = {
-        esp32.KEY_COMPONENTS: {
-            "esphome/noise-c": {
-                esp32.KEY_REPO: None,
-                esp32.KEY_REF: "0.1.15",
-                esp32.KEY_PATH: None,
-            },
-        },
-    }
-
-    captured: dict[str, set[str] | None] = {}
-
-    # A converted (non-managed) library the batch still resolves, so the loop
-    # wiring its override_path into the manifest is exercised for real too.
-    converted = MagicMock()
-    converted.get_sanitized_name.return_value = "esphome/other-lib"
-    converted.path = tmp_path / "pio_components" / "other-lib"
-
-    def fake_generate_idf_components(libraries, managed=None):
-        captured["managed"] = managed
-        return [converted]
-
-    monkeypatch.setattr(esp32, "generate_idf_components", fake_generate_idf_components)
-
-    esp32._write_idf_component_yml()
-
-    assert captured["managed"] == {"esphome/noise-c"}
-    # The managed component itself is still written into the manifest deps
-    # directly (from KEY_COMPONENTS), just not converted a second time.
-    yml_path = tmp_path / "src" / "idf_component.yml"
-    assert yml_path.is_file()
-    contents = yml_path.read_text(encoding="utf-8")
-    assert "esphome/noise-c" in contents
-    assert "0.1.15" in contents
-    # The converted library the batch DID return is still wired in.
-    assert "esphome/other-lib" in contents
-    assert str(converted.path) in contents
-
-
-def test_write_idf_component_yml_empty_managed_when_no_components(
-    tmp_path: Path,
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """No managed components registered yet (no add_idf_component calls) ->
-    an empty managed set, matching the pre-existing (unfiltered) behavior."""
-    _setup_core(tmp_path)
-    CORE.data[esp32.KEY_ESP32] = {esp32.KEY_COMPONENTS: {}}
-
-    captured: dict[str, set[str] | None] = {}
-
-    def fake_generate_idf_components(libraries, managed=None):
-        captured["managed"] = managed
-        return []
-
-    monkeypatch.setattr(esp32, "generate_idf_components", fake_generate_idf_components)
-
-    esp32._write_idf_component_yml()
-
-    assert captured["managed"] == set()

tests/unit_tests/components/test_espnow.py

@@ -0,0 +1,48 @@
+"""Tests for the espnow component's final validation."""
+
+import pytest
+
+from esphome.components.esp32.const import (
+    VARIANT_ESP32C3,
+    VARIANT_ESP32H2,
+    VARIANT_ESP32P4,
+)
+from esphome.components.espnow import _validate_variant
+import esphome.config_validation as cv
+import esphome.final_validate as fv
+from esphome.types import ConfigType
+
+
+def _run(
+    monkeypatch, variant: str, full_config: dict, config: ConfigType
+) -> ConfigType:
+    monkeypatch.setattr("esphome.components.espnow.get_esp32_variant", lambda: variant)
+    token = fv.full_config.set(full_config)
+    try:
+        return _validate_variant(config)
+    finally:
+        fv.full_config.reset(token)
+
+
+def test_variant_with_native_wifi_passes(monkeypatch) -> None:
+    """A variant with a native Wi-Fi PHY needs no shim; config passes through."""
+    config = {"id": "espnow"}
+    assert _run(monkeypatch, VARIANT_ESP32C3, {}, config) is config
+
+
+def test_radioless_non_p4_variant_rejected(monkeypatch) -> None:
+    """Radio-less variants without any ESP-NOW path are rejected outright."""
+    with pytest.raises(cv.Invalid, match="not supported"):
+        _run(monkeypatch, VARIANT_ESP32H2, {}, {})
+
+
+def test_p4_without_esp32_hosted_rejected(monkeypatch) -> None:
+    """The P4 needs the esp32_hosted shim to supply the esp_now_* symbols."""
+    with pytest.raises(cv.Invalid, match="esp32_hosted"):
+        _run(monkeypatch, VARIANT_ESP32P4, {}, {})
+
+
+def test_p4_with_esp32_hosted_passes(monkeypatch) -> None:
+    """The P4 with esp32_hosted present validates; config passes through."""
+    config = {"id": "espnow"}
+    assert _run(monkeypatch, VARIANT_ESP32P4, {"esp32_hosted": {}}, config) is config

tests/unit_tests/conftest.py

@@ -9,7 +9,7 @@ not be part of a unit test suite.
 
 """
 
-from collections.abc import Generator
+from collections.abc import Callable, Generator
 import os
 from pathlib import Path
 import sys
@@ -137,3 +137,40 @@ def mock_get_component() -> Generator[Mock, None, None]:
     """Mock get_component for config module."""
     with patch("esphome.config.get_component") as mock:
         yield mock
+
+
+@pytest.fixture
+def held_lock() -> Callable[..., Callable[..., None]]:
+    """Factory for a ``FileLock.acquire`` fake held by another downloader.
+
+    Each poll writes the next chunk to ``part`` (or runs it, for a callable)
+    and raises ``Timeout``; when the chunks run out the part is removed,
+    ``land()`` runs, and the acquire succeeds (also for any later job, so
+    ``land`` must be idempotent).
+    """
+    from filelock import Timeout
+
+    def make(
+        part: Path,
+        chunks: list[bytes | Callable[[], None]],
+        land: Callable[[], None],
+    ) -> Callable[..., None]:
+        polls = iter(chunks)
+
+        def acquire(*args, **kwargs) -> None:
+            try:
+                chunk = next(polls)
+            except StopIteration:
+                part.unlink(missing_ok=True)
+                land()
+                return
+            if callable(chunk):
+                chunk()
+            else:
+                part.parent.mkdir(parents=True, exist_ok=True)
+                part.write_bytes(chunk)
+            raise Timeout("held")
+
+        return acquire
+
+    return make

tests/unit_tests/test_espidf_clang_tidy.py

@@ -3,22 +3,12 @@
 import json
 import os
 from pathlib import Path
-from types import SimpleNamespace
 from unittest.mock import patch
 
 import pytest
-import yaml
 
 from esphome.espidf import clang_tidy
-from esphome.espidf.clang_tidy import (
-    _arduino_excluded_stubs,
-    _convert_pio_libs,
-    _esphome_manifest_deps,
-    _Settings,
-    _setup_core,
-    _write_tidy_project,
-)
-import esphome.espidf.component as espidf_component
+from esphome.espidf.clang_tidy import _Settings, _setup_core, _write_tidy_project
 
 REPO_ROOT = Path(__file__).resolve().parents[2]
 
@@ -79,108 +69,6 @@ def test_setup_core_sets_arduino_env(
     assert os.environ["ESPHOME_ARDUINO_COMPONENT"] == expected
 
 
-def test_esphome_manifest_deps_reads_repo_manifest() -> None:
-    """Returns the top-level dependency names from esphome/idf_component.yml,
-    independent of any per-dependency framework rules."""
-    manifest = yaml.safe_load(
-        (REPO_ROOT / "esphome" / "idf_component.yml").read_text(encoding="utf-8")
-    )
-
-    deps = _esphome_manifest_deps()
-
-    assert isinstance(deps, set)
-    assert "esphome/noise-c" in deps
-    assert "esphome/libsodium" in deps
-    # Cross-check against a fresh parse instead of hardcoding the manifest's
-    # whole key list, so this doesn't need updating whenever a dependency is
-    # added or removed.
-    assert deps == set(manifest["dependencies"])
-
-
-def test_convert_pio_libs_arduino_framework_passes_empty_managed(
-    tmp_path: Path,
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """On Arduino, ESPHome's manifest entries for noise-c/libsodium are
-    rule-gated off (arduino-esp32 brings its own libsodium), so nothing
-    provides them there -- managed must be empty and they go through the
-    PlatformIO-library converter as before."""
-    monkeypatch.setattr(clang_tidy, "_parse_lib_deps", lambda ini, framework: [])
-
-    captured: dict[str, set[str] | None] = {}
-
-    # A converted library the batch resolves, so the loop wiring its
-    # override_path into the returned deps mapping is exercised for real too.
-    converted = SimpleNamespace(
-        get_sanitized_name=lambda: "esphome/other-lib",
-        path=tmp_path / "other-lib",
-    )
-
-    def fake_generate_idf_components(libraries, managed=None):
-        captured["managed"] = managed
-        return [converted]
-
-    monkeypatch.setattr(
-        espidf_component, "generate_idf_components", fake_generate_idf_components
-    )
-
-    result = _convert_pio_libs(tmp_path / "platformio.ini", "arduino")
-
-    assert captured["managed"] == set()
-    assert result == {
-        "esphome/other-lib": {"override_path": str(tmp_path / "other-lib")}
-    }
-
-
-def test_convert_pio_libs_espidf_framework_passes_manifest_deps(
-    tmp_path: Path,
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """On ESP-IDF, libraries ESPHome's own manifest already provides as
-    managed components (noise-c, libsodium, ...) must be passed through as
-    ``managed`` so the converter skips them -- converting them too would make
-    IDF see the same requirement twice."""
-    monkeypatch.setattr(clang_tidy, "_parse_lib_deps", lambda ini, framework: [])
-
-    captured: dict[str, set[str] | None] = {}
-
-    def fake_generate_idf_components(libraries, managed=None):
-        captured["managed"] = managed
-        return []
-
-    monkeypatch.setattr(
-        espidf_component, "generate_idf_components", fake_generate_idf_components
-    )
-
-    result = _convert_pio_libs(tmp_path / "platformio.ini", "espidf")
-
-    assert captured["managed"] == _esphome_manifest_deps()
-    assert "esphome/noise-c" in captured["managed"]
-    assert result == {}
-
-
-def test_arduino_excluded_stubs_skips_components_esphome_manifest_provides(
-    tmp_path: Path,
-) -> None:
-    """A component ESPHome's own idf_component.yml declares for real (e.g.
-    espressif/lan867x for ethernet) must not be stubbed away -- stubbing it
-    would silently disable ethernet on Arduino. A component that is only ever
-    bundled by arduino-esp32 (never in ESPHome's own manifest) still gets a
-    stub so the arduino-bundled copy doesn't clash with noise-c's libsodium."""
-    deps = _arduino_excluded_stubs(tmp_path)
-
-    # lan867x is a real ESPHome dependency (esphome/idf_component.yml), so it
-    # must be excluded from the stub set.
-    assert "espressif/lan867x" not in deps
-    # espressif/libsodium (arduino-esp32's bundled copy) is a different
-    # package from ESPHome's own esphome/libsodium, so it's still stubbed.
-    assert "espressif/libsodium" in deps
-    stub_info = deps["espressif/libsodium"]
-    assert stub_info["version"] == "*"
-    stub_path = Path(stub_info["override_path"])
-    assert (stub_path / "CMakeLists.txt").is_file()
-
-
 def test_idedata_from_tidy_project(tmp_path) -> None:
     """The tidy TU's compile entry is assembled into consumer-shaped idedata."""
     compile_commands = tmp_path / "compile_commands.json"

tests/unit_tests/test_espidf_component.py

@@ -803,112 +803,6 @@ def test_generate_idf_components_lib_ignore_filters_top_level_and_dependencies(
     assert download_salts == [hashlib.sha256(b"b,c").hexdigest()[:8]]
 
 
-def test_generate_idf_components_managed_filters_top_level_and_dependencies(
-    tmp_path: Path,
-    monkeypatch: pytest.MonkeyPatch,
-    esp32_idf_core: None,
-) -> None:
-    # managed (e.g. noise-c/libsodium already declared via add_idf_component)
-    # must drop B at the top level and C when discovered as a dependency of A,
-    # exactly like lib_ignore -- neither may be resolved, downloaded, or wired
-    # into a manifest.
-    manifests = {
-        "esphome/A": {
-            "name": "A",
-            "dependencies": [
-                {"owner": "esphome", "name": "C", "version": "==1.10021.0"}
-            ],
-        },
-        "esphome/B": {"name": "B"},
-    }
-
-    download_salts: list[str] = []
-
-    def fake_download(self, force=False, salt="", namespace=""):
-        download_salts.append(salt)
-        self.path = tmp_path / self.get_sanitized_name().replace("/", "__")
-        (self.path / "src").mkdir(parents=True, exist_ok=True)
-        (self.path / "src" / "x.c").write_text("int x;")
-        (self.path / "library.json").write_text(json.dumps(manifests[self.name]))
-
-    monkeypatch.setattr(IDFComponent, "download", fake_download)
-
-    resolve_calls: list[str] = []
-
-    def fake_resolve(owner, pkgname, requirements):
-        resolve_calls.append(pkgname)
-        return owner, pkgname, "1.0.0", f"http://x/{pkgname}.tar.gz", None
-
-    monkeypatch.setattr(
-        esphome.platformio.library, "_resolve_registry_version", fake_resolve
-    )
-
-    top = generate_idf_components(
-        [Library("esphome/A", "1.0.0", None), Library("esphome/B", "1.0.0", None)],
-        managed={"esphome/B", "esphome/C"},
-    )
-
-    assert [c.name for c in top] == ["esphome/A"]
-    # Managed libraries were never resolved (and therefore never downloaded).
-    assert resolve_calls == ["A"]
-    # The managed dependency is not wired into A's manifest.
-    assert top[0].dependencies == []
-    # managed changes the generated wiring just like lib_ignore, so the cache
-    # path is salted the same way.
-    assert download_salts == [hashlib.sha256(b"b,c").hexdigest()[:8]]
-
-
-def test_generate_idf_components_lib_ignore_and_managed_combine_into_salt(
-    tmp_path: Path,
-    monkeypatch: pytest.MonkeyPatch,
-    esp32_idf_core: None,
-) -> None:
-    # lib_ignore and managed both contribute to the same exclusion set, so a
-    # config using both gets a salt reflecting the union of the two sources
-    # rather than either alone.
-    manifests = {
-        "esphome/A": {"name": "A"},
-        "esphome/D": {"name": "D"},
-        "esphome/E": {"name": "E"},
-    }
-
-    download_salts: list[str] = []
-
-    def fake_download(self, force=False, salt="", namespace=""):
-        download_salts.append(salt)
-        self.path = tmp_path / self.get_sanitized_name().replace("/", "__")
-        (self.path / "src").mkdir(parents=True, exist_ok=True)
-        (self.path / "src" / "x.c").write_text("int x;")
-        (self.path / "library.json").write_text(json.dumps(manifests[self.name]))
-
-    monkeypatch.setattr(IDFComponent, "download", fake_download)
-
-    resolve_calls: list[str] = []
-
-    def fake_resolve(owner, pkgname, requirements):
-        resolve_calls.append(pkgname)
-        return owner, pkgname, "1.0.0", f"http://x/{pkgname}.tar.gz", None
-
-    monkeypatch.setattr(
-        esphome.platformio.library, "_resolve_registry_version", fake_resolve
-    )
-    monkeypatch.setattr(CORE, "platformio_options", {"lib_ignore": ["D"]})
-
-    top = generate_idf_components(
-        [
-            Library("esphome/A", "1.0.0", None),
-            Library("esphome/D", "1.0.0", None),
-            Library("esphome/E", "1.0.0", None),
-        ],
-        managed={"esphome/E"},
-    )
-
-    assert [c.name for c in top] == ["esphome/A"]
-    assert resolve_calls == ["A"]
-    # The salt reflects BOTH lib_ignore's "D" and managed's "E" together.
-    assert download_salts == [hashlib.sha256(b"d,e").hexdigest()[:8]]
-
-
 def test_generate_idf_components_handles_dependency_cycle(
     tmp_path: Path,
     monkeypatch: pytest.MonkeyPatch,

tests/unit_tests/test_framework_helpers.py

@@ -2353,3 +2353,20 @@ def test_discard_partial_download_logs_undeletable(
     ):
         framework_helpers.discard_partial_download(dest)
     assert "Could not remove" in caplog.text
+
+
+def test_downloaded_bytes_reports_what_is_on_disk(tmp_path: Path) -> None:
+    """Part file first, then the landed file, both capped at size; else 0."""
+    dest = tmp_path / "archive"
+    assert framework_helpers.downloaded_bytes(dest, 4) == 0
+    part = tmp_path / "archive.part"
+    part.write_bytes(b"ab")
+    assert framework_helpers.downloaded_bytes(dest, 4) == 2
+    part.write_bytes(b"abcdef")
+    assert framework_helpers.downloaded_bytes(dest, 4) == 4
+    part.unlink()
+    dest.write_bytes(b"abc")
+    assert framework_helpers.downloaded_bytes(dest, 4) == 3
+    assert framework_helpers.downloaded_bytes(dest) == 3
+    dest.write_bytes(b"abcdef")
+    assert framework_helpers.downloaded_bytes(dest, 4) == 4

tests/unit_tests/test_platformio_prefetch.py

@@ -454,23 +454,96 @@ def test_uri_fetch_job_waits_out_a_briefly_held_lock(tmp_path: Path) -> None:
     assert dl_path.read_bytes() == b"data"
 
 
-def test_lock_deadline_leaves_download_to_the_holder(tmp_path: Path) -> None:
-    """A lock held past the deadline means another process is fetching the
-    same file; skipping cleanly beats a misleading failure warning. The
-    tracker is still polled so a parked worker observes cancellation."""
+@pytest.mark.parametrize("staged", [b"", b"ab"])
+def test_lock_deadline_leaves_download_to_the_holder(
+    tmp_path: Path, staged: bytes
+) -> None:
+    """A lock held past the deadline is another process's download; skip
+    cleanly, polling the tracker with what the holder has staged so far."""
     dl_path = tmp_path / "archive"
+    (tmp_path / "archive.prefetch.part").write_bytes(staged)
     ticks: list[int] = []
     with (
         patch("esphome.framework_helpers.download_with_resume") as mock_download,
         patch("filelock.FileLock.acquire", side_effect=Timeout("held")),
-        patch.object(pf, "_DOWNLOAD_LOCK_TIMEOUT", 0),
+        patch("esphome.framework_helpers.DOWNLOAD_LOCK_TIMEOUT", 0),
     ):
         pf._uri_fetch_job(MagicMock(), "https://x/a.zip", dl_path, 4)(ticks.append)
     mock_download.assert_not_called()
-    assert ticks == [0]
+    assert ticks == [len(staged)]
     assert not dl_path.exists()
 
 
+@pytest.mark.parametrize(
+    ("job", "part_name", "chunks", "expected"),
+    [
+        (
+            lambda dl_path: pf._registry_fetch_job(
+                MagicMock(), "https://x/a.tar.gz", dl_path, "ab" * 32, 4
+            ),
+            "archive.part",
+            [b"a", b"abc"],
+            [1, 3, 4],
+        ),
+        (
+            lambda dl_path: pf._uri_fetch_job(
+                MagicMock(), "https://x/a.zip", dl_path, 4
+            ),
+            "archive.prefetch.part",
+            [b"ab"],
+            [2, 4],
+        ),
+    ],
+    ids=["registry", "uri"],
+)
+def test_lock_wait_reports_the_holders_progress(
+    tmp_path: Path,
+    caplog: pytest.LogCaptureFixture,
+    held_lock,
+    job,
+    part_name: str,
+    chunks: list[bytes],
+    expected: list[int],
+) -> None:
+    """A waiting job reports the holder's part file (the staging one for a
+    URL job), then the full size once the holder lands the archive."""
+    dl_path = tmp_path / "archive"
+    ticks: list[int] = []
+    acquire = held_lock(
+        tmp_path / part_name, chunks, lambda: dl_path.write_bytes(b"abcd")
+    )
+    with (
+        patch("esphome.framework_helpers.download_with_resume") as mock_download,
+        patch("filelock.FileLock.acquire", side_effect=acquire),
+        patch("filelock.FileLock.release"),
+        caplog.at_level(logging.INFO),
+    ):
+        job(dl_path)(ticks.append)
+    mock_download.assert_not_called()
+    assert ticks == expected
+    assert caplog.text.count("Waiting for another process downloading archive") == 1
+
+
+def test_uri_lock_wait_prefers_the_landed_archive(tmp_path: Path, held_lock) -> None:
+    """Between the holder's promotion rename and its release the staging
+    part is gone; the landed cache file is credited instead of 0."""
+    dl_path = tmp_path / "archive"
+    ticks: list[int] = []
+    acquire = held_lock(
+        tmp_path / "archive.prefetch.part",
+        [b"ab", lambda: dl_path.write_bytes(b"abcd")],
+        lambda: None,
+    )
+    with (
+        patch("esphome.framework_helpers.download_with_resume") as mock_download,
+        patch("filelock.FileLock.acquire", side_effect=acquire),
+        patch("filelock.FileLock.release"),
+    ):
+        pf._uri_fetch_job(MagicMock(), "https://x/a.zip", dl_path, 4)(ticks.append)
+    mock_download.assert_not_called()
+    assert ticks == [2, 4, 4]
+
+
 def test_registry_lock_deadline_skips_registration(tmp_path: Path) -> None:
     """A registry job that lost the download race to another process
     must not stamp a nonexistent archive into pio's usage.db."""
@@ -479,7 +552,7 @@ def test_registry_lock_deadline_skips_registration(tmp_path: Path) -> None:
     with (
         patch("esphome.framework_helpers.download_with_resume") as mock_download,
         patch("filelock.FileLock.acquire", side_effect=Timeout("held")),
-        patch.object(pf, "_DOWNLOAD_LOCK_TIMEOUT", 0),
+        patch("esphome.framework_helpers.DOWNLOAD_LOCK_TIMEOUT", 0),
     ):
         pf._registry_fetch_job(manager, "https://x/a.tar.gz", dl_path, "ab" * 32, 4)(
             lambda done: None
@@ -1576,7 +1649,7 @@ def test_preinstall_runs_dependency_waves(tmp_path: Path) -> None:
         {"name": "SPI"},
     ]
     m.dependency_to_spec.side_effect = lambda dep: _FakeSpec(name=dep["name"])
-    pf._preinstall(m, [("noise-c@0.1.21", _FakeSpec(name="noise-c"))])
+    pf._preinstall(m, [("noise-c@0.1.24", _FakeSpec(name="noise-c"))])
     assert installed == ["noise-c", "libsodium"]  # dep deduped, SPI left out
     # The dep wave carries its compatibility so _install searches qualified
     dep_call = m._install.call_args_list[-1]
@@ -1596,7 +1669,7 @@ def test_preinstall_dependency_wave_skips_seen_names(tmp_path: Path) -> None:
     m._install.side_effect = lambda spec, skip_dependencies, compatibility=None: (
         installed.append(getattr(spec, "name", str(spec)))
     )
-    pf._preinstall(m, [("noise-c@0.1.21", _FakeSpec(name="noise-c"))])
+    pf._preinstall(m, [("noise-c@0.1.24", _FakeSpec(name="noise-c"))])
     assert installed == ["noise-c"]
 
 

tests/unit_tests/test_platformio_registry.py

@@ -8,6 +8,7 @@ import os
 from pathlib import Path
 from unittest.mock import MagicMock, patch
 
+from filelock import Timeout
 import pytest
 
 from esphome.core import EsphomeError
@@ -540,16 +541,13 @@ def test_prefetch_packages_skips_freshly_installed_dest(tmp_path: Path) -> None:
     dest = tmp_path / "a"
     dest.mkdir()
 
-    from contextlib import contextmanager
-
-    @contextmanager
-    def marker_appears_under_lock(path, **kwargs):
+    def marker_appears_under_lock(*args, **kwargs):
         # Simulates the concurrent build finishing while we waited
         (dest / ".esphome_extracted").touch()
-        yield
 
     with (
-        patch("filelock.FileLock", side_effect=marker_appears_under_lock),
+        patch("filelock.FileLock.acquire", side_effect=marker_appears_under_lock),
+        patch("filelock.FileLock.release"),
         patch.object(registry, "download_with_resume") as mock_download,
         patch.object(
             registry, "registry_download", side_effect=_resolve_for({"a": 10})
@@ -559,6 +557,69 @@ def test_prefetch_packages_skips_freshly_installed_dest(tmp_path: Path) -> None:
     mock_download.assert_not_called()
 
 
+def test_prefetch_packages_waits_with_the_holders_progress(
+    tmp_path: Path, held_lock
+) -> None:
+    """A worker parked on another build's lock reports that build's part
+    file, then the full size once the marker appears."""
+    dest = tmp_path / "a"
+    dest.mkdir()
+    ticks: list[int] = []
+    part = tmp_path / "dl" / "a-1.0.part"
+
+    def installed_and_pruned() -> None:
+        # install_package touches the marker, then unlinks the archive
+        (dest / ".esphome_extracted").touch()
+        part.unlink()
+
+    acquire = held_lock(
+        part,
+        [lambda: None, b"abc", installed_and_pruned],
+        (dest / ".esphome_extracted").touch,
+    )
+
+    def fake_batch(header, jobs):
+        for _name, _size, fetch in jobs:
+            fetch(ticks.append)
+        return []
+
+    with (
+        patch("filelock.FileLock.acquire", side_effect=acquire),
+        patch("filelock.FileLock.release"),
+        patch.object(registry, "run_batch_downloads", side_effect=fake_batch),
+        patch.object(registry, "download_with_resume") as mock_download,
+        patch.object(
+            registry, "registry_download", side_effect=_resolve_for({"a": 10, "b": 5})
+        ),
+    ):
+        registry.prefetch_packages(
+            [("a", "1.0", dest, []), ("b", "2.0", tmp_path / "b", [])],
+            tmp_path / "dl",
+        )
+    assert ticks == [0, 3, 10, 10]
+    mock_download.assert_called_once()
+
+
+def test_prefetch_packages_leaves_a_long_held_lock_to_its_holder(
+    tmp_path: Path,
+) -> None:
+    """Past the deadline the worker skips; install_package waits on the same
+    lock later and verifies whatever the holder produced."""
+    with (
+        patch("filelock.FileLock.acquire", side_effect=Timeout("held")),
+        patch("esphome.framework_helpers.DOWNLOAD_LOCK_TIMEOUT", 0),
+        patch.object(registry, "download_with_resume") as mock_download,
+        patch.object(
+            registry, "registry_download", side_effect=_resolve_for({"a": 10, "b": 5})
+        ),
+    ):
+        registry.prefetch_packages(
+            [("a", "1.0", tmp_path / "a", []), ("b", "2.0", tmp_path / "b", [])],
+            tmp_path / "dl",
+        )
+    mock_download.assert_not_called()
+
+
 def test_already_installed_probe(tmp_path: Path) -> None:
     """Both arms of the marker probe the prefetch worker keys on."""
     dest = tmp_path / "pkg"