Warn instead of failing when the post-build idedata is unusable

esphome/arduino8266/toolchain.py

@@ -91,11 +91,17 @@ def run_compile(config: ConfigType, verbose: bool) -> int:
         return rc
 
     _print_size_summary(build_dir)
-    if get_idedata() is None:
-        _LOGGER.warning(
-            "Could not generate idedata from %s",
-            build_dir / "compile_commands.json",
-        )
+    try:
+        idedata = get_idedata()
+    except EsphomeError as err:
+        # The firmware already built; idedata is a bonus artifact here
+        _LOGGER.warning("Could not generate idedata: %s", err)
+    else:
+        if idedata is None:
+            _LOGGER.warning(
+                "Could not generate idedata from %s",
+                build_dir / "compile_commands.json",
+            )
     return 0
 
 

tests/unit_tests/test_arduino8266_toolchain.py

@@ -337,3 +337,24 @@ def test_warn_ignored_platformio_options(caplog: pytest.LogCaptureFixture) -> No
     assert "native 'arduino' toolchain" in caplog.text
     assert "lib_ignore" not in caplog.text
     assert "upload_speed" not in caplog.text
+
+
+def test_run_compile_idedata_error_does_not_fail_build(
+    tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """An unusable compile DB after a successful build warns, never fails."""
+    with (
+        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
+        patch.object(framework, "get_build_env", return_value={}),
+        patch("esphome.build_gen.arduino8266.write_project"),
+        patch.object(toolchain.subprocess, "run", return_value=MagicMock(returncode=0)),
+        patch.object(toolchain, "_write_compile_commands"),
+        patch.object(toolchain, "_print_size_summary"),
+        patch.object(
+            toolchain,
+            "get_idedata",
+            side_effect=EsphomeError("compile database is unusable"),
+        ),
+    ):
+        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
+    assert "Could not generate idedata: compile database is unusable" in caplog.text