[esp32] Redefine __FILE__ to the basename so assert paths stay out of RAM (#19106)

esphome/components/esp32/__init__.py

@@ -2609,6 +2609,13 @@ async def to_code(config):
     # NVS finds stored preferences by key, so preference key migration is possible
     cg.add_define("USE_PREFERENCE_KEY_LOOKUP")
     cg.add_build_flag("-Wl,-z,noexecstack")
+    # assert(), HAL_ASSERT and ESP_ERROR_CHECK bake __FILE__ into rodata, and
+    # IDF's noflash placement puts the flash driver's copies in DRAM. The
+    # basename keeps the panic output useful at a fraction of the size.
+    # __FILE_NAME__ is a GCC 12 builtin; IDF 5.0 still ships GCC 11.2.
+    if idf_version() >= cv.Version(5, 1, 0):
+        cg.add_build_flag("-D__FILE__=__FILE_NAME__")
+        cg.add_build_flag("-Wno-builtin-macro-redefined")
     # Deferred so KEY_COMPONENTS is fully populated -- see the coroutine.
     CORE.add_job(_finalize_arduino_aware_flags)
     cg.add_define("ESPHOME_BOARD", config[CONF_BOARD])

tests/component_tests/esp32/config/file_macro_idf_5_0.yaml

@@ -0,0 +1,8 @@
+esphome:
+  name: test
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+    version: 5.0.6

tests/component_tests/esp32/test_esp32.py

@@ -658,6 +658,27 @@ def test_platformio_arduino_enables_reproducible_build(
     assert sdkconfig.get("CONFIG_APP_REPRODUCIBLE_BUILD") is True
 
 
+@pytest.mark.parametrize(
+    ("config_file", "expected"),
+    [
+        ("reproducible_build.yaml", True),
+        ("reproducible_build_arduino.yaml", True),
+        ("file_macro_idf_5_0.yaml", False),
+    ],
+)
+def test_file_macro_is_basename_only(
+    generate_main: Callable[[str | Path], str],
+    component_config_path: Callable[[str], Path],
+    config_file: str,
+    expected: bool,
+) -> None:
+    """__FILE__ becomes the basename on GCC 12 toolchains; IDF 5.0 (GCC 11) is skipped."""
+    generate_main(component_config_path(config_file))
+
+    assert ("-D__FILE__=__FILE_NAME__" in CORE.build_flags) is expected
+    assert ("-Wno-builtin-macro-redefined" in CORE.build_flags) is expected
+
+
 def test_native_idf_enables_reproducible_build(
     component_config_path: Callable[[str], Path],
 ) -> None: