From 1918e17c21600bf9381b40cc6c42e6e1d99d02e7 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 20 Mar 2026 19:05:01 -1000
Subject: [PATCH] [core] Inline yield_with_select_ on all embedded platforms

Inline yield_with_select_ for ESP8266/RP2040 (socket_delay) and
no-socket (delay) paths in addition to the LWIP_FAST_SELECT path.
Only the select() fallback (host platform) remains in the .cpp.

This ensures yield_with_select_ is inlined into the loop on all
embedded platforms, not just ESP32/LibreTiny.
---
 esphome/core/application.cpp | 18 +++---------------
 esphome/core/application.h   | 25 +++++++++++++++++++------
 2 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/esphome/core/application.cpp b/esphome/core/application.cpp
index 8cf225fb74..064760915a 100644
--- a/esphome/core/application.cpp
+++ b/esphome/core/application.cpp
@@ -550,13 +550,10 @@ void Application::unregister_socket_fd(int fd) {
 
 #endif
 
-// When USE_LWIP_FAST_SELECT is defined, yield_with_select_ is inlined in application.h
-#if !defined(USE_SOCKET_SELECT_SUPPORT) || !defined(USE_LWIP_FAST_SELECT)
+// Only the select() fallback path remains in the .cpp — all other paths are inlined in application.h
+#if defined(USE_SOCKET_SELECT_SUPPORT) && !defined(USE_LWIP_FAST_SELECT)
 void Application::yield_with_select_(uint32_t delay_ms) {
-  // Delay while monitoring sockets. When delay_ms is 0, always yield() to ensure other tasks run.
-#if defined(USE_SOCKET_SELECT_SUPPORT)
   // Fallback select() path (host platform and any future platforms without fast select).
-  // ESP32 and LibreTiny are excluded by the #if above — they use the fast path.
   if (!this->socket_fds_.empty()) [[likely]] {
     // Update fd_set if socket list has changed
     if (this->socket_fds_changed_) [[unlikely]] {
@@ -603,17 +600,8 @@ void Application::yield_with_select_(uint32_t delay_ms) {
   }
   // No sockets registered or select() failed - use regular delay
   delay(delay_ms);
-#elif (defined(USE_ESP8266) || defined(USE_RP2040)) && defined(USE_SOCKET_IMPL_LWIP_TCP)
-  // No select support but can wake on socket activity
-  // ESP8266: via esp_schedule()
-  // RP2040: via __sev()/__wfe() hardware sleep/wake
-  socket::socket_delay(delay_ms);
-#else
-  // No select support, use regular delay
-  delay(delay_ms);
-#endif
 }
-#endif  // !defined(USE_SOCKET_SELECT_SUPPORT) || !defined(USE_LWIP_FAST_SELECT)
+#endif  // defined(USE_SOCKET_SELECT_SUPPORT) && !defined(USE_LWIP_FAST_SELECT)
 
 // App storage — asm label shares the linker symbol with "extern Application App".
 // char[] is trivially destructible, so no __cxa_atexit or destructor chain is emitted.
diff --git a/esphome/core/application.h b/esphome/core/application.h
index 9cbae42e22..f916b6604b 100644
--- a/esphome/core/application.h
+++ b/esphome/core/application.h
@@ -43,7 +43,8 @@
 #endif  // USE_SOCKET_SELECT_SUPPORT
 #if (defined(USE_ESP8266) || defined(USE_RP2040)) && defined(USE_SOCKET_IMPL_LWIP_TCP)
 namespace esphome::socket {
-void socket_wake();  // NOLINT(readability-redundant-declaration)
+void socket_wake();              // NOLINT(readability-redundant-declaration)
+void socket_delay(uint32_t ms);  // NOLINT(readability-redundant-declaration)
 }  // namespace esphome::socket
 #endif
 #ifdef USE_BINARY_SENSOR
@@ -635,10 +636,11 @@ class Application {
   void feed_wdt_arch_();
 
   /// Perform a delay while also monitoring socket file descriptors for readiness
-#if defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_LWIP_FAST_SELECT)
-  inline void ESPHOME_ALWAYS_INLINE yield_with_select_(uint32_t delay_ms);
-#else
+#if defined(USE_SOCKET_SELECT_SUPPORT) && !defined(USE_LWIP_FAST_SELECT)
+  // select() fallback path is too complex to inline (host platform)
   void yield_with_select_(uint32_t delay_ms);
+#else
+  inline void ESPHOME_ALWAYS_INLINE yield_with_select_(uint32_t delay_ms);
 #endif
 
 #if defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_WAKE_LOOP_THREADSAFE) && !defined(USE_LWIP_FAST_SELECT)
@@ -894,8 +896,10 @@ inline void ESPHOME_ALWAYS_INLINE Application::loop() {
   }
 }
 
-#if defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_LWIP_FAST_SELECT)
+// Inline yield_with_select_ for all paths except the select() fallback
+#if !defined(USE_SOCKET_SELECT_SUPPORT) || defined(USE_LWIP_FAST_SELECT)
 inline void ESPHOME_ALWAYS_INLINE Application::yield_with_select_(uint32_t delay_ms) {
+#if defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_LWIP_FAST_SELECT)
   // Fast path (ESP32/LibreTiny): reads rcvevent directly from cached lwip_sock pointers.
   // Safe because this runs on the main loop which owns socket lifetime (create, read, close).
   if (delay_ms == 0) [[unlikely]] {
@@ -919,7 +923,16 @@ inline void ESPHOME_ALWAYS_INLINE Application::yield_with_select_(uint32_t delay
   // Without USE_WAKE_LOOP_THREADSAFE, only hooked socket callbacks wake the task —
   // background tasks won't call wake, so this degrades to a pure timeout (same as old select path).
   ulTaskNotifyTake(pdTRUE, pdMS_TO_TICKS(delay_ms));
+#elif (defined(USE_ESP8266) || defined(USE_RP2040)) && defined(USE_SOCKET_IMPL_LWIP_TCP)
+  // No select support but can wake on socket activity
+  // ESP8266: via esp_schedule()
+  // RP2040: via __sev()/__wfe() hardware sleep/wake
+  socket::socket_delay(delay_ms);
+#else
+  // No select support, use regular delay
+  delay(delay_ms);
+#endif
 }
-#endif  // defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_LWIP_FAST_SELECT)
+#endif  // !defined(USE_SOCKET_SELECT_SUPPORT) || defined(USE_LWIP_FAST_SELECT)
 
 }  // namespace esphome