Simplify to uint8_t index, add friend declarations, fix tests

- Drop 9-bit index scheme in favor of plain uint8_t (max 255 unique
  source names, overflow warns in Python and returns 0)
- Add friend declarations for setup()/original_setup() so generated
  code can call protected set_component_source_()
- Move get_component_log_str() out of line
- Fix test mocks to provide CORE.data dict

esphome/core/component.cpp

@@ -274,6 +274,10 @@ void Component::call() {
       break;
   }
 }
+const LogString *Component::get_component_log_str() const {
+  return this->component_source_index_ == 0 ? LOG_STR("<unknown>")
+                                            : component_source_lookup(this->component_source_index_);
+}
 bool Component::should_warn_of_blocking(uint32_t blocking_time) {
   // Convert centisecond threshold to milliseconds for comparison
   uint32_t threshold_ms = static_cast<uint32_t>(this->warn_if_blocking_over_) * 10U;
@@ -544,6 +548,6 @@ void clear_setup_priority_overrides() {
 #endif
 
 // Weak default for component_source_lookup - overridden by generated code
-__attribute__((weak)) const LogString *component_source_lookup(uint16_t) { return LOG_STR("<unknown>"); }
+__attribute__((weak)) const LogString *component_source_lookup(uint8_t) { return LOG_STR("<unknown>"); }
 
 }  // namespace esphome

esphome/core/component.h

@@ -11,6 +11,10 @@
 #include "esphome/core/log.h"
 #include "esphome/core/optional.h"
 
+// Forward declarations for friend access from codegen-generated setup()
+void setup();           // NOLINT(readability-redundant-declaration) - may be declared in Arduino.h
+void original_setup();  // NOLINT(readability-redundant-declaration)
+
 namespace esphome {
 
 // Forward declaration for LogString
@@ -79,11 +83,6 @@ inline constexpr uint8_t STATUS_LED_WARNING = 0x08;
 inline constexpr uint8_t STATUS_LED_ERROR = 0x10;
 // Component loop override flag uses bit 5 (set at registration time)
 inline constexpr uint8_t COMPONENT_HAS_LOOP = 0x20;
-// High bit of 9-bit component_source index (bit 6 of component_state_)
-inline constexpr uint8_t COMPONENT_SOURCE_HIGH_BIT = 0x40;
-// Mask for the 9th bit of the component source index (bit 8)
-inline constexpr uint16_t COMPONENT_SOURCE_INDEX_HIGH = 0x100;
-
 // Remove before 2026.8.0
 enum class RetryResult { DONE, RETRY };
 
@@ -91,7 +90,7 @@ inline constexpr uint8_t WARN_IF_BLOCKING_OVER_CS = 5U;  // 50ms in centiseconds
 
 /// Lookup component source name by index (1-based). Generated by Python codegen.
 /// Weak default returns "<unknown>" so builds without codegen still link.
-const LogString *component_source_lookup(uint16_t index);
+const LogString *component_source_lookup(uint8_t index);
 
 class Component {
  public:
@@ -151,10 +150,7 @@ class Component {
    */
   virtual void on_powerdown() {}
 
-  uint8_t get_component_state() const {
-    // Mask out COMPONENT_SOURCE_HIGH_BIT — it's internal to component source indexing
-    return this->component_state_ & ~COMPONENT_SOURCE_HIGH_BIT;
-  }
+  uint8_t get_component_state() const { return this->component_state_; }
 
   /** Reset this component back to the construction state to allow setup to run again.
    *
@@ -300,31 +296,21 @@ class Component {
    *
    * Returns LOG_STR("<unknown>") if source not set
    */
-  const LogString *get_component_log_str() const {
-    uint16_t idx = this->component_source_index_;
-    if (this->component_state_ & COMPONENT_SOURCE_HIGH_BIT)
-      idx |= COMPONENT_SOURCE_INDEX_HIGH;
-    return idx == 0 ? LOG_STR("<unknown>") : component_source_lookup(idx);
-  }
+  const LogString *get_component_log_str() const;
 
   bool should_warn_of_blocking(uint32_t blocking_time);
 
  protected:
   friend class Application;
+  friend void ::setup();
+  friend void ::original_setup();
 
   /** Set where this component was loaded from for some debug messages.
    *
    * This is set by the ESPHome core during setup, and should not be called manually.
    * @param index 1-based index into the component source lookup table (0 = not set)
    */
-  void set_component_source_(uint16_t index) {
-    this->component_source_index_ = static_cast<uint8_t>(index & 0xFF);
-    if (index & COMPONENT_SOURCE_INDEX_HIGH) {
-      this->component_state_ |= COMPONENT_SOURCE_HIGH_BIT;
-    } else {
-      this->component_state_ &= ~COMPONENT_SOURCE_HIGH_BIT;
-    }
-  }
+  void set_component_source_(uint8_t index) { this->component_source_index_ = index; }
 
   virtual void call_setup();
   void call_dump_config_();
@@ -550,8 +536,7 @@ class Component {
   /// Bit 3: STATUS_LED_WARNING
   /// Bit 4: STATUS_LED_ERROR
   /// Bit 5: Has overridden loop() (set at registration time)
-  /// Bit 6: High bit of 9-bit component_source index
-  /// Bit 7: Unused - reserved for future expansion
+  /// Bits 6-7: Unused - reserved for future expansion
   uint8_t component_state_{0x00};
   volatile bool pending_enable_loop_{false};  ///< ISR-safe flag for enable_loop_soon_any_context
 };

esphome/cpp_helpers.py

@@ -26,8 +26,8 @@ _LOGGER = logging.getLogger(__name__)
 
 _COMPONENT_SOURCE_DOMAIN = "component_source_pool"
 
-# Maximum unique component source names (9-bit index, 0 = not set)
-_MAX_COMPONENT_SOURCES = 510
+# Maximum unique component source names (8-bit index, 0 = not set)
+_MAX_COMPONENT_SOURCES = 0xFF  # 255
 
 
 @dataclass
@@ -71,9 +71,12 @@ def register_component_source(name: str) -> int:
         return pool.sources[name]
     idx = len(pool.sources) + 1
     if idx > _MAX_COMPONENT_SOURCES:
-        raise ValueError(
-            f"Too many unique component source names (max {_MAX_COMPONENT_SOURCES}), got {idx}: '{name}'"
+        _LOGGER.warning(
+            "Too many unique component source names (max %d), '%s' will show as '<unknown>'",
+            _MAX_COMPONENT_SOURCES,
+            name,
         )
+        return 0
     pool.sources[name] = idx
     _ensure_source_table_registered()
     return idx
@@ -107,7 +110,7 @@ def _generate_source_table_code(
 
     entries = ", ".join(var_names)
     lines.append(f"static const char *const {table_var}[] PROGMEM = {{{entries}}};")
-    lines.append(f"const LogString *{lookup_fn}(uint16_t index) {{")
+    lines.append(f"const LogString *{lookup_fn}(uint8_t index) {{")
     lines.append(f'  if (index == 0 || index > {count}) return LOG_STR("<unknown>");')
     lines.append("  return reinterpret_cast<const LogString *>(")
     lines.append(f"    progmem_read_ptr(&{table_var}[index - 1]));")

tests/unit_tests/test_cpp_helpers.py

@@ -23,7 +23,7 @@ async def test_register_component(monkeypatch):
     app_mock = Mock(register_component_=Mock(return_value=var))
     monkeypatch.setattr(ch, "App", app_mock)
 
-    core_mock = Mock(component_ids=["foo.bar"])
+    core_mock = Mock(component_ids=["foo.bar"], data={})
     monkeypatch.setattr(ch, "CORE", core_mock)
 
     add_mock = Mock()
@@ -59,7 +59,7 @@ async def test_register_component__with_setup_priority(monkeypatch):
     app_mock = Mock(register_component_=Mock(return_value=var))
     monkeypatch.setattr(ch, "App", app_mock)
 
-    core_mock = Mock(component_ids=["foo.bar"])
+    core_mock = Mock(component_ids=["foo.bar"], data={})
     monkeypatch.setattr(ch, "CORE", core_mock)
 
     add_mock = Mock()