Log the high performance override; pin range bounds; fold compile test into the existing build

esphome/components/network/__init__.py

@@ -32,7 +32,8 @@ CONF_TCP_SEND_BUFFER = "tcp_send_buffer"
 # stock ESP-IDF default (5744 bytes) stalls bursty senders like a Bluetooth
 # proxy streaming GATT notifications. Bounds follow the lwIP guidance for the
 # default 1440 byte MSS: at least 2 x MSS, at most 65535 without window
-# scaling.
+# scaling. The cap is kept even when window scaling is on (high performance
+# with PSRAM) as a deliberate conservative bound.
 TCP_SEND_BUFFER_MIN = 2880
 TCP_SEND_BUFFER_MAX = 65535
 
@@ -463,6 +464,11 @@ async def to_code(config):
     # After the high performance block so an explicit size wins over the
     # bundle's 65534 (last write wins in the sdkconfig store).
     if (tcp_send_buffer := config.get(CONF_TCP_SEND_BUFFER)) is not None:
+        if CORE.is_esp32 and should_enable:
+            _LOGGER.info(
+                "TCP send buffer set to %d bytes by configuration (overriding high performance value)",
+                tcp_send_buffer,
+            )
         add_idf_sdkconfig_option("CONFIG_LWIP_TCP_SND_BUF_DEFAULT", tcp_send_buffer)
 
     if CORE.is_nrf52:

tests/component_tests/network/test_tcp_send_buffer.py

@@ -14,16 +14,23 @@ import pytest
 from voluptuous import Invalid
 
 from esphome import config_validation as cv
-from esphome.components.esp32.const import KEY_VARIANT, VARIANT_ESP32
-from esphome.components.network import CONFIG_SCHEMA
-from esphome.const import KEY_FRAMEWORK_VERSION, PlatformFramework
+from esphome.components.esp32.const import (
+    KEY_SDKCONFIG_OPTIONS,
+    KEY_VARIANT,
+    VARIANT_ESP32,
+)
+from esphome.components.network import (
+    CONF_TCP_SEND_BUFFER,
+    CONFIG_SCHEMA,
+    TCP_SEND_BUFFER_MAX,
+    TCP_SEND_BUFFER_MIN,
+)
+from esphome.const import KEY_ESP32, KEY_FRAMEWORK_VERSION, PlatformFramework
 from esphome.core import CORE
 from tests.component_tests.types import SetCoreConfigCallable
 
 
 def _sdkconfig_option(name: str) -> int | None:
-    from esphome.components.esp32.const import KEY_ESP32, KEY_SDKCONFIG_OPTIONS
-
     return CORE.data[KEY_ESP32][KEY_SDKCONFIG_OPTIONS].get(name)
 
 
@@ -44,6 +51,18 @@ def test_tcp_send_buffer_overrides_high_performance(
     assert _sdkconfig_option("CONFIG_LWIP_TCP_SND_BUF_DEFAULT") == 16384
 
 
+@pytest.mark.parametrize("value", [TCP_SEND_BUFFER_MIN, TCP_SEND_BUFFER_MAX])
+def test_boundary_values_accepted(
+    set_core_config: SetCoreConfigCallable, value: int
+) -> None:
+    set_core_config(
+        PlatformFramework.ESP32_IDF,
+        core_data={KEY_FRAMEWORK_VERSION: cv.Version(5, 5, 5)},
+        platform_data={KEY_VARIANT: VARIANT_ESP32},
+    )
+    assert CONFIG_SCHEMA({"tcp_send_buffer": value})[CONF_TCP_SEND_BUFFER] == value
+
+
 @pytest.mark.parametrize("value", ["1kB", "128kB"])
 def test_out_of_range_rejected(
     set_core_config: SetCoreConfigCallable, value: str

tests/components/network/test-tcp-send-buffer.esp32-idf.yaml

@@ -1,6 +0,0 @@
-wifi:
-  ssid: MySSID
-  password: password1
-
-network:
-  tcp_send_buffer: 32kB

tests/components/network/test.esp32-idf.yaml

@@ -2,3 +2,4 @@
 
 network:
   enable_high_performance: true
+  tcp_send_buffer: 32kB