From 0bfb294f322624cbeb6e1beb467e8e108335a89f Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Thu, 26 Feb 2026 06:38:23 -1000
Subject: [PATCH] Update comments to reflect multi-platform fast select scope

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 esphome/core/application.cpp    | 5 +++--
 esphome/core/application.h      | 7 ++++---
 esphome/core/lwip_fast_select.c | 9 +++++----
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/esphome/core/application.cpp b/esphome/core/application.cpp
index 6f367de14d..83aa281aa5 100644
--- a/esphome/core/application.cpp
+++ b/esphome/core/application.cpp
@@ -616,8 +616,9 @@ void Application::unregister_socket_fd(int fd) {
       continue;
 
     // Swap with last element and pop - O(1) removal since order doesn't matter.
-    // No need to unhook the netconn callback on ESP32 — all LwIP sockets share
-    // the same static event_callback, and the socket will be closed by the caller.
+    // No need to unhook the netconn callback on fast select platforms — all LwIP
+    // sockets share the same static event_callback, and the socket will be closed
+    // by the caller.
     if (i < this->socket_fds_.size() - 1)
       this->socket_fds_[i] = this->socket_fds_.back();
     this->socket_fds_.pop_back();
diff --git a/esphome/core/application.h b/esphome/core/application.h
index 42e5993cb7..0cc29af8e7 100644
--- a/esphome/core/application.h
+++ b/esphome/core/application.h
@@ -511,9 +511,10 @@ class Application {
 
 #ifdef USE_SOCKET_SELECT_SUPPORT
   /// Fast path for Socket::ready() via friendship - skips negative fd check.
-  /// Main loop only — on ESP32, reads rcvevent via lwip_socket_dbg_get_socket()
-  /// which has no refcount; safe only because the main loop owns socket lifetime
-  /// (creates, reads, and closes sockets on the same thread).
+  /// Main loop only — with USE_LWIP_FAST_SELECT, reads rcvevent via
+  /// lwip_socket_dbg_get_socket(), which has no refcount; safe only because
+  /// the main loop owns socket lifetime (creates, reads, and closes sockets
+  /// on the same thread).
 #ifdef USE_LWIP_FAST_SELECT
   bool is_socket_ready_(int fd) const { return esphome_lwip_socket_has_data(fd); }
 #else
diff --git a/esphome/core/lwip_fast_select.c b/esphome/core/lwip_fast_select.c
index b6a4ac2961..88cf23b67e 100644
--- a/esphome/core/lwip_fast_select.c
+++ b/esphome/core/lwip_fast_select.c
@@ -5,7 +5,8 @@
 // 1. lwip/priv/sockets_priv.h conflicts with C++ compilation units
 // 2. The netconn callback is a C function pointer
 //
-// defines.h is force-included by the build system (-include flag), providing USE_LWIP_FAST_SELECT etc.
+// USE_ESP32 and USE_LIBRETINY platform flags (-D) control compilation of this file.
+// See the guard at the bottom of the header comment for details.
 //
 // Thread safety analysis
 // ======================
@@ -104,9 +105,9 @@
 //     critical sections). Multiple concurrent xTaskNotifyGive calls are safe —
 //     the notification count simply increments.
 
-// USE_ESP32 and USE_LIBRETINY are build flags (-D), always available to .c files.
-// USE_LWIP_FAST_SELECT is in the generated defines.h (force-included for .cpp but
-// may not reach .c files on all build systems), so we use platform flags here.
+// USE_ESP32 and USE_LIBRETINY are compiler -D flags, so they are always visible in this .c file.
+// Feature macros like USE_LWIP_FAST_SELECT may come from generated headers that are not included here,
+// so this implementation is enabled based on platform flags instead of USE_LWIP_FAST_SELECT.
 #if defined(USE_ESP32) || defined(USE_LIBRETINY)
 
 // LwIP headers must come first — they define netconn_callback, struct lwip_sock, etc.