From 44860ff5125af133276f8a66ded1790c9fd23637 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <3060199+jesserockz@users.noreply.github.com>
Date: Tue, 25 Aug 2026 00:22:41 -0500
Subject: [PATCH] [time] Skip posix_tz.cpp when no timezone is configured
 (#18680)

---
 esphome/components/time/__init__.py          | 8 ++++++++
 tests/benchmarks/components/time/__init__.py | 2 +-
 tests/components/time/__init__.py            | 2 +-
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/esphome/components/time/__init__.py b/esphome/components/time/__init__.py
index 94ff6ab051..7ad084493c 100644
--- a/esphome/components/time/__init__.py
+++ b/esphome/components/time/__init__.py
@@ -9,6 +9,7 @@ from esphome import automation
 from esphome.automation import Condition
 import esphome.codegen as cg
 from esphome.components.zephyr import zephyr_add_prj_conf
+from esphome.config_helpers import filter_source_files_from_defines
 import esphome.config_validation as cv
 from esphome.const import (
     CONF_AT,
@@ -475,3 +476,10 @@ async def to_code(config):
 async def time_has_time_to_code(config, condition_id, template_arg, args):
     paren = await cg.get_variable(config[CONF_ID])
     return cg.new_Pvariable(condition_id, template_arg, paren)
+
+
+# posix_tz.cpp is fully #ifdef'd on USE_TIME_TIMEZONE, set only when a
+# timezone is configured or detected.
+FILTER_SOURCE_FILES = filter_source_files_from_defines(
+    {"posix_tz.cpp": "USE_TIME_TIMEZONE"}
+)
diff --git a/tests/benchmarks/components/time/__init__.py b/tests/benchmarks/components/time/__init__.py
index 7f68003e29..8b4fd955f2 100644
--- a/tests/benchmarks/components/time/__init__.py
+++ b/tests/benchmarks/components/time/__init__.py
@@ -4,6 +4,6 @@ from tests.testing_helpers import ComponentManifestOverride
 
 def override_manifest(manifest: ComponentManifestOverride) -> None:
     async def to_code(config):
-        cg.add_build_flag("-DUSE_TIME_TIMEZONE")
+        cg.add_define("USE_TIME_TIMEZONE")
 
     manifest.to_code = to_code
diff --git a/tests/components/time/__init__.py b/tests/components/time/__init__.py
index 7f68003e29..8b4fd955f2 100644
--- a/tests/components/time/__init__.py
+++ b/tests/components/time/__init__.py
@@ -4,6 +4,6 @@ from tests.testing_helpers import ComponentManifestOverride
 
 def override_manifest(manifest: ComponentManifestOverride) -> None:
     async def to_code(config):
-        cg.add_build_flag("-DUSE_TIME_TIMEZONE")
+        cg.add_define("USE_TIME_TIMEZONE")
 
     manifest.to_code = to_code