[socket] Compile the lookup and client link helpers only when required (#20002)

esphome/components/socket/__init__.py

@@ -140,6 +140,17 @@ def require_wake_loop_threadsafe() -> None:
     cg.add_define("USE_SOCKET_SELECT_SUPPORT")
 
 
+def require_ipv4_resolve() -> None:
+    """Compile the shared IPv4 lookup; call from a consumer's to_code."""
+    cg.add_define("USE_SOCKET_IPV4_RESOLVE")
+
+
+def require_tcp_client_link() -> None:
+    """Compile the reconnecting TCP client link; call from a consumer's to_code."""
+    require_ipv4_resolve()
+    cg.add_define("USE_SOCKET_TCP_CLIENT_LINK")
+
+
 CONFIG_SCHEMA = cv.Schema(
     {
         cv.SplitDefault(
@@ -184,11 +195,14 @@ async def to_code(config: ConfigType) -> None:
 
 
 # Each implementation file is fully #ifdef'd on the define set in to_code
-# for the selected implementation.
+# for the selected implementation. The helper files compile only for
+# consumers that called the matching require_ function.
 FILTER_SOURCE_FILES = filter_source_files_from_defines(
     {
         "lwip_raw_tcp_impl.cpp": "USE_SOCKET_IMPL_LWIP_TCP",
         "bsd_sockets_impl.cpp": "USE_SOCKET_IMPL_BSD_SOCKETS",
         "lwip_sockets_impl.cpp": "USE_SOCKET_IMPL_LWIP_SOCKETS",
+        "ipv4_resolve.cpp": "USE_SOCKET_IPV4_RESOLVE",
+        "tcp_client_link.cpp": "USE_SOCKET_TCP_CLIENT_LINK",
     }
 )

esphome/core/defines.h

@@ -417,6 +417,8 @@
 #define USE_SENDSPIN_VISUALIZER
 #define USE_SENDSPIN_PORT 8928  // NOLINT
 #define USE_SOCKET_IMPL_BSD_SOCKETS
+#define USE_SOCKET_IPV4_RESOLVE
+#define USE_SOCKET_TCP_CLIENT_LINK
 #define USE_LWIP_FAST_SELECT
 
 #define USE_SPEAKER

tests/components/socket/__init__.py

@@ -2,6 +2,7 @@
 # shadowing the stdlib module -- no test_*.py (Python-level) tests can live here.
 # required for cpp unit testing.
 import esphome.codegen as cg
+from esphome.components import socket as socket_component
 from tests.testing_helpers import ComponentManifestOverride
 
 
@@ -12,5 +13,7 @@ def override_manifest(manifest: ComponentManifestOverride) -> None:
     async def to_code_testing(config):
         await real_to_code(config)
         cg.add_define("USE_NETWORK_IPV6", True)
+        # The gtests link against the filtered helper files.
+        socket_component.require_tcp_client_link()
 
     manifest.to_code = to_code_testing

tests/integration/fixtures/external_components/ipv4_resolve_test_component/__init__.py

@@ -1,4 +1,5 @@
 import esphome.codegen as cg
+from esphome.components import socket
 import esphome.config_validation as cv
 from esphome.const import CONF_ID
 from esphome.types import ConfigType
@@ -18,5 +19,6 @@ CONFIG_SCHEMA = cv.Schema(
 
 
 async def to_code(config: ConfigType) -> None:
+    socket.require_ipv4_resolve()
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)

tests/integration/fixtures/external_components/tcp_client_link_test_component/__init__.py

@@ -1,4 +1,5 @@
 import esphome.codegen as cg
+from esphome.components import socket
 from esphome.components.const import CONF_HOST
 import esphome.config_validation as cv
 from esphome.const import CONF_ID, CONF_PORT
@@ -28,6 +29,7 @@ CONFIG_SCHEMA = cv.Schema(
 
 
 async def to_code(config: ConfigType) -> None:
+    socket.require_tcp_client_link()
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)
     cg.add(var.set_host(config[CONF_HOST]))

tests/unit_tests/components/socket/test_socket_source_filter.py

@@ -0,0 +1,38 @@
+"""Tests for the socket component's source filtering and require functions."""
+
+from unittest.mock import patch
+
+from esphome.components import socket
+from esphome.core import Define
+
+
+def test_helper_files_filtered_until_required() -> None:
+    """ipv4_resolve.cpp and tcp_client_link.cpp compile only when required."""
+    with patch("esphome.config_helpers.CORE") as mock_core:
+        mock_core.defines = set()
+        filtered = socket.FILTER_SOURCE_FILES()
+        assert "ipv4_resolve.cpp" in filtered
+        assert "tcp_client_link.cpp" in filtered
+
+        mock_core.defines = {Define("USE_SOCKET_IPV4_RESOLVE")}
+        filtered = socket.FILTER_SOURCE_FILES()
+        assert "ipv4_resolve.cpp" not in filtered
+        assert "tcp_client_link.cpp" in filtered
+
+        mock_core.defines = {
+            Define("USE_SOCKET_IPV4_RESOLVE"),
+            Define("USE_SOCKET_TCP_CLIENT_LINK"),
+        }
+        filtered = socket.FILTER_SOURCE_FILES()
+        assert "ipv4_resolve.cpp" not in filtered
+        assert "tcp_client_link.cpp" not in filtered
+
+
+def test_require_tcp_client_link_pulls_in_the_resolver() -> None:
+    """require_tcp_client_link() sets both defines; the link reads the resolver."""
+    with patch.object(socket.cg, "add_define") as add_define:
+        socket.require_tcp_client_link()
+    assert {call.args[0] for call in add_define.call_args_list} == {
+        "USE_SOCKET_IPV4_RESOLVE",
+        "USE_SOCKET_TCP_CLIENT_LINK",
+    }