Trim comments

esphome/writer.py

@@ -337,12 +337,13 @@ def copy_src_tree():
     else:
         try:
             existing = json.loads(build_info_json_path.read_text(encoding="utf-8"))
-            if (
+            if not isinstance(existing, dict) or (
                 existing.get("config_hash") != config_hash
                 or existing.get("esphome_version") != __version__
             ):
+                # Non-object JSON is stale like every other damage case
                 sources_changed = True
-        except (json.JSONDecodeError, KeyError, OSError):
+        except (json.JSONDecodeError, OSError):
             sources_changed = True
 
     # Write build_info header and JSON metadata

tests/unit_tests/test_writer.py

@@ -2072,9 +2072,10 @@ def test_copy_src_tree_detects_config_hash_change(
         )
     )
 
-    # Create existing build_info_data.h
+    # Both sources must exist to reach the JSON comparison branch
     build_info_h_path = esphome_core_path / "build_info_data.h"
     build_info_h_path.write_text("// old build_info_data.h")
+    (esphome_core_path / "build_info_data.cpp").write_text("// old")
 
     # Setup mocks
     mock_core.relative_src_path.side_effect = src_path.joinpath
@@ -2136,9 +2137,10 @@ def test_copy_src_tree_detects_version_change(
         )
     )
 
-    # Create existing build_info_data.h
+    # Both sources must exist to reach the JSON comparison branch
     build_info_h_path = esphome_core_path / "build_info_data.h"
     build_info_h_path.write_text("// old build_info_data.h")
+    (esphome_core_path / "build_info_data.cpp").write_text("// old")
 
     # Setup mocks
     mock_core.relative_src_path.side_effect = src_path.joinpath
@@ -2186,9 +2188,60 @@ def test_copy_src_tree_handles_invalid_build_info_json(
     build_info_json_path = build_path / "build_info.json"
     build_info_json_path.write_text("invalid json {{{")
 
-    # Create existing build_info_data.h
+    # Both sources must exist to reach the JSON comparison branch
     build_info_h_path = esphome_core_path / "build_info_data.h"
     build_info_h_path.write_text("// old build_info_data.h")
+    (esphome_core_path / "build_info_data.cpp").write_text("// old")
+
+    # Setup mocks
+    mock_core.relative_src_path.side_effect = src_path.joinpath
+    mock_core.relative_build_path.side_effect = build_path.joinpath
+    mock_core.defines = []
+    mock_core.config_hash = 0xDEADBEEF
+    mock_core.comment = ""
+    mock_core.target_platform = "test_platform"
+    mock_core.config = {}
+    mock_iter_components.return_value = []
+    mock_walk_files.return_value = []
+
+    with (
+        patch("esphome.writer.__version__", "2025.1.0-dev"),
+        patch("esphome.writer.importlib.import_module") as mock_import,
+    ):
+        mock_import.side_effect = AttributeError
+        copy_src_tree()
+
+    # Verify build_info files were created despite invalid JSON
+    assert build_info_h_path.exists()
+    new_json = json.loads(build_info_json_path.read_text())
+    assert new_json["config_hash"] == 0xDEADBEEF
+
+
+@patch("esphome.writer.CORE")
+@patch("esphome.writer.iter_components")
+@patch("esphome.writer.walk_files")
+def test_copy_src_tree_handles_non_dict_build_info_json(
+    mock_walk_files: MagicMock,
+    mock_iter_components: MagicMock,
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Valid JSON that is not an object (no .get) is treated as stale."""
+    # Setup directory structure
+    src_path = tmp_path / "src"
+    src_path.mkdir()
+    esphome_core_path = src_path / "esphome" / "core"
+    esphome_core_path.mkdir(parents=True)
+    build_path = tmp_path / "build"
+    build_path.mkdir()
+
+    build_info_json_path = build_path / "build_info.json"
+    build_info_json_path.write_text("[]")
+
+    # Both sources must exist to reach the JSON comparison branch
+    build_info_h_path = esphome_core_path / "build_info_data.h"
+    build_info_h_path.write_text("// old build_info_data.h")
+    (esphome_core_path / "build_info_data.cpp").write_text("// old")
 
     # Setup mocks
     mock_core.relative_src_path.side_effect = src_path.joinpath