Add build info to image (#12425)

Co-authored-by: J. Nick Koston <nick+github@koston.org>
Co-authored-by: J. Nick Koston <nick@home-assistant.io>
Co-authored-by: J. Nick Koston <nick@koston.org>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

tests/unit_tests/test_writer.py

@@ -1,6 +1,10 @@
 """Test writer module functionality."""
 
 from collections.abc import Callable
+from contextlib import contextmanager
+from dataclasses import dataclass
+from datetime import datetime
+import json
 import os
 from pathlib import Path
 import stat
@@ -20,6 +24,9 @@ from esphome.writer import (
     clean_all,
     clean_build,
     clean_cmake_cache,
+    copy_src_tree,
+    generate_build_info_data_h,
+    get_build_info,
     storage_should_clean,
     update_storage_json,
     write_cpp,
@@ -1165,3 +1172,721 @@ def test_clean_build_reraises_for_other_errors(
     finally:
         # Cleanup - restore write permission so tmp_path cleanup works
         os.chmod(subdir, stat.S_IRWXU)
+
+
+# Tests for get_build_info()
+
+
+@patch("esphome.writer.CORE")
+def test_get_build_info_new_build(
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test get_build_info returns new build_time when no existing build_info.json."""
+    build_info_path = tmp_path / "build_info.json"
+    mock_core.relative_build_path.return_value = build_info_path
+    mock_core.config_hash = 0x12345678
+
+    config_hash, build_time, build_time_str = get_build_info()
+
+    assert config_hash == 0x12345678
+    assert isinstance(build_time, int)
+    assert build_time > 0
+    assert isinstance(build_time_str, str)
+    # Verify build_time_str format matches expected pattern
+    assert len(build_time_str) >= 19  # e.g., "2025-12-15 16:27:44 +0000"
+
+
+@patch("esphome.writer.CORE")
+def test_get_build_info_always_returns_current_time(
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test get_build_info always returns current build_time."""
+    build_info_path = tmp_path / "build_info.json"
+    mock_core.relative_build_path.return_value = build_info_path
+    mock_core.config_hash = 0x12345678
+
+    # Create existing build_info.json with matching config_hash and version
+    existing_build_time = 1700000000
+    existing_build_time_str = "2023-11-14 22:13:20 +0000"
+    build_info_path.write_text(
+        json.dumps(
+            {
+                "config_hash": 0x12345678,
+                "build_time": existing_build_time,
+                "build_time_str": existing_build_time_str,
+                "esphome_version": "2025.1.0-dev",
+            }
+        )
+    )
+
+    with patch("esphome.writer.__version__", "2025.1.0-dev"):
+        config_hash, build_time, build_time_str = get_build_info()
+
+    assert config_hash == 0x12345678
+    # get_build_info now always returns current time
+    assert build_time != existing_build_time
+    assert build_time > existing_build_time
+    assert build_time_str != existing_build_time_str
+
+
+@patch("esphome.writer.CORE")
+def test_get_build_info_config_changed(
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test get_build_info returns new build_time when config hash changed."""
+    build_info_path = tmp_path / "build_info.json"
+    mock_core.relative_build_path.return_value = build_info_path
+    mock_core.config_hash = 0xABCDEF00  # Different from existing
+
+    # Create existing build_info.json with different config_hash
+    existing_build_time = 1700000000
+    build_info_path.write_text(
+        json.dumps(
+            {
+                "config_hash": 0x12345678,  # Different
+                "build_time": existing_build_time,
+                "build_time_str": "2023-11-14 22:13:20 +0000",
+                "esphome_version": "2025.1.0-dev",
+            }
+        )
+    )
+
+    with patch("esphome.writer.__version__", "2025.1.0-dev"):
+        config_hash, build_time, build_time_str = get_build_info()
+
+    assert config_hash == 0xABCDEF00
+    assert build_time != existing_build_time  # New time generated
+    assert build_time > existing_build_time
+
+
+@patch("esphome.writer.CORE")
+def test_get_build_info_version_changed(
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test get_build_info returns new build_time when ESPHome version changed."""
+    build_info_path = tmp_path / "build_info.json"
+    mock_core.relative_build_path.return_value = build_info_path
+    mock_core.config_hash = 0x12345678
+
+    # Create existing build_info.json with different version
+    existing_build_time = 1700000000
+    build_info_path.write_text(
+        json.dumps(
+            {
+                "config_hash": 0x12345678,
+                "build_time": existing_build_time,
+                "build_time_str": "2023-11-14 22:13:20 +0000",
+                "esphome_version": "2024.12.0",  # Old version
+            }
+        )
+    )
+
+    with patch("esphome.writer.__version__", "2025.1.0-dev"):  # New version
+        config_hash, build_time, build_time_str = get_build_info()
+
+    assert config_hash == 0x12345678
+    assert build_time != existing_build_time  # New time generated
+    assert build_time > existing_build_time
+
+
+@patch("esphome.writer.CORE")
+def test_get_build_info_invalid_json(
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test get_build_info handles invalid JSON gracefully."""
+    build_info_path = tmp_path / "build_info.json"
+    mock_core.relative_build_path.return_value = build_info_path
+    mock_core.config_hash = 0x12345678
+
+    # Create invalid JSON file
+    build_info_path.write_text("not valid json {{{")
+
+    config_hash, build_time, build_time_str = get_build_info()
+
+    assert config_hash == 0x12345678
+    assert isinstance(build_time, int)
+    assert build_time > 0
+
+
+@patch("esphome.writer.CORE")
+def test_get_build_info_missing_keys(
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test get_build_info handles missing keys gracefully."""
+    build_info_path = tmp_path / "build_info.json"
+    mock_core.relative_build_path.return_value = build_info_path
+    mock_core.config_hash = 0x12345678
+
+    # Create JSON with missing keys
+    build_info_path.write_text(json.dumps({"config_hash": 0x12345678}))
+
+    with patch("esphome.writer.__version__", "2025.1.0-dev"):
+        config_hash, build_time, build_time_str = get_build_info()
+
+    assert config_hash == 0x12345678
+    assert isinstance(build_time, int)
+    assert build_time > 0
+
+
+@patch("esphome.writer.CORE")
+def test_get_build_info_build_time_str_format(
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test get_build_info returns correctly formatted build_time_str."""
+    build_info_path = tmp_path / "build_info.json"
+    mock_core.relative_build_path.return_value = build_info_path
+    mock_core.config_hash = 0x12345678
+
+    config_hash, build_time, build_time_str = get_build_info()
+
+    # Verify the format matches "%Y-%m-%d %H:%M:%S %z"
+    # e.g., "2025-12-15 16:27:44 +0000"
+    parsed = datetime.strptime(build_time_str, "%Y-%m-%d %H:%M:%S %z")
+    assert parsed.year >= 2024
+
+
+def test_generate_build_info_data_h_format() -> None:
+    """Test generate_build_info_data_h produces correct header content."""
+    config_hash = 0x12345678
+    build_time = 1700000000
+    build_time_str = "2023-11-14 22:13:20 +0000"
+
+    result = generate_build_info_data_h(config_hash, build_time, build_time_str)
+
+    assert "#pragma once" in result
+    assert "#define ESPHOME_CONFIG_HASH 0x12345678U" in result
+    assert "#define ESPHOME_BUILD_TIME 1700000000" in result
+    assert 'ESPHOME_BUILD_TIME_STR[] = "2023-11-14 22:13:20 +0000"' in result
+
+
+def test_generate_build_info_data_h_esp8266_progmem() -> None:
+    """Test generate_build_info_data_h includes PROGMEM for ESP8266."""
+    result = generate_build_info_data_h(0xABCDEF01, 1700000000, "test")
+
+    # Should have ESP8266 PROGMEM conditional
+    assert "#ifdef USE_ESP8266" in result
+    assert "#include <pgmspace.h>" in result
+    assert "PROGMEM" in result
+
+
+def test_generate_build_info_data_h_hash_formatting() -> None:
+    """Test generate_build_info_data_h formats hash with leading zeros."""
+    # Test with small hash value that needs leading zeros
+    result = generate_build_info_data_h(0x00000001, 0, "test")
+    assert "#define ESPHOME_CONFIG_HASH 0x00000001U" in result
+
+    # Test with larger hash value
+    result = generate_build_info_data_h(0xFFFFFFFF, 0, "test")
+    assert "#define ESPHOME_CONFIG_HASH 0xffffffffU" in result
+
+
+@patch("esphome.writer.CORE")
+@patch("esphome.writer.iter_components")
+@patch("esphome.writer.walk_files")
+def test_copy_src_tree_writes_build_info_files(
+    mock_walk_files: MagicMock,
+    mock_iter_components: MagicMock,
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test copy_src_tree writes build_info_data.h and build_info.json."""
+    # 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()
+
+    # Create mock source files for defines.h and version.h
+    mock_defines_h = esphome_core_path / "defines.h"
+    mock_defines_h.write_text("// mock defines.h")
+    mock_version_h = esphome_core_path / "version.h"
+    mock_version_h.write_text("// mock version.h")
+
+    # Create mock FileResource that returns our temp files
+    @dataclass(frozen=True)
+    class MockFileResource:
+        package: str
+        resource: str
+        _path: Path
+
+        @contextmanager
+        def path(self):
+            yield self._path
+
+    # Create mock resources for defines.h and version.h (required by copy_src_tree)
+    mock_resources = [
+        MockFileResource(
+            package="esphome.core",
+            resource="defines.h",
+            _path=mock_defines_h,
+        ),
+        MockFileResource(
+            package="esphome.core",
+            resource="version.h",
+            _path=mock_version_h,
+        ),
+    ]
+
+    # Create mock component with resources
+    mock_component = MagicMock()
+    mock_component.resources = mock_resources
+
+    # Setup mocks
+    mock_core.relative_src_path.side_effect = lambda *args: src_path.joinpath(*args)
+    mock_core.relative_build_path.side_effect = lambda *args: build_path.joinpath(*args)
+    mock_core.defines = []
+    mock_core.config_hash = 0xDEADBEEF
+    mock_core.target_platform = "test_platform"
+    mock_core.config = {}
+    mock_iter_components.return_value = [("core", mock_component)]
+    mock_walk_files.return_value = []
+
+    # Create mock module without copy_files attribute (causes AttributeError which is caught)
+    mock_module = MagicMock(spec=[])  # Empty spec = no copy_files attribute
+
+    with (
+        patch("esphome.writer.__version__", "2025.1.0-dev"),
+        patch("esphome.writer.importlib.import_module", return_value=mock_module),
+    ):
+        copy_src_tree()
+
+    # Verify build_info_data.h was written
+    build_info_h_path = esphome_core_path / "build_info_data.h"
+    assert build_info_h_path.exists()
+    build_info_h_content = build_info_h_path.read_text()
+    assert "#define ESPHOME_CONFIG_HASH 0xdeadbeefU" in build_info_h_content
+    assert "#define ESPHOME_BUILD_TIME" in build_info_h_content
+    assert "ESPHOME_BUILD_TIME_STR" in build_info_h_content
+
+    # Verify build_info.json was written
+    build_info_json_path = build_path / "build_info.json"
+    assert build_info_json_path.exists()
+    build_info_json = json.loads(build_info_json_path.read_text())
+    assert build_info_json["config_hash"] == 0xDEADBEEF
+    assert "build_time" in build_info_json
+    assert "build_time_str" in build_info_json
+    assert build_info_json["esphome_version"] == "2025.1.0-dev"
+
+
+@patch("esphome.writer.CORE")
+@patch("esphome.writer.iter_components")
+@patch("esphome.writer.walk_files")
+def test_copy_src_tree_detects_config_hash_change(
+    mock_walk_files: MagicMock,
+    mock_iter_components: MagicMock,
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test copy_src_tree detects when config_hash changes."""
+    # 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()
+
+    # Create existing build_info.json with different config_hash
+    build_info_json_path = build_path / "build_info.json"
+    build_info_json_path.write_text(
+        json.dumps(
+            {
+                "config_hash": 0x12345678,  # Different from current
+                "build_time": 1700000000,
+                "build_time_str": "2023-11-14 22:13:20 +0000",
+                "esphome_version": "2025.1.0-dev",
+            }
+        )
+    )
+
+    # Create existing build_info_data.h
+    build_info_h_path = esphome_core_path / "build_info_data.h"
+    build_info_h_path.write_text("// old build_info_data.h")
+
+    # Setup mocks
+    mock_core.relative_src_path.side_effect = lambda *args: src_path.joinpath(*args)
+    mock_core.relative_build_path.side_effect = lambda *args: build_path.joinpath(*args)
+    mock_core.defines = []
+    mock_core.config_hash = 0xDEADBEEF  # Different from existing
+    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 updated due to config_hash change
+    assert build_info_h_path.exists()
+    new_content = build_info_h_path.read_text()
+    assert "0xdeadbeef" in new_content.lower()
+
+    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_detects_version_change(
+    mock_walk_files: MagicMock,
+    mock_iter_components: MagicMock,
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test copy_src_tree detects when esphome_version changes."""
+    # 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()
+
+    # Create existing build_info.json with different version
+    build_info_json_path = build_path / "build_info.json"
+    build_info_json_path.write_text(
+        json.dumps(
+            {
+                "config_hash": 0xDEADBEEF,
+                "build_time": 1700000000,
+                "build_time_str": "2023-11-14 22:13:20 +0000",
+                "esphome_version": "2024.12.0",  # Old version
+            }
+        )
+    )
+
+    # Create existing build_info_data.h
+    build_info_h_path = esphome_core_path / "build_info_data.h"
+    build_info_h_path.write_text("// old build_info_data.h")
+
+    # Setup mocks
+    mock_core.relative_src_path.side_effect = lambda *args: src_path.joinpath(*args)
+    mock_core.relative_build_path.side_effect = lambda *args: build_path.joinpath(*args)
+    mock_core.defines = []
+    mock_core.config_hash = 0xDEADBEEF
+    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"),  # New version
+        patch("esphome.writer.importlib.import_module") as mock_import,
+    ):
+        mock_import.side_effect = AttributeError
+        copy_src_tree()
+
+    # Verify build_info files were updated due to version change
+    assert build_info_h_path.exists()
+    new_json = json.loads(build_info_json_path.read_text())
+    assert new_json["esphome_version"] == "2025.1.0-dev"
+
+
+@patch("esphome.writer.CORE")
+@patch("esphome.writer.iter_components")
+@patch("esphome.writer.walk_files")
+def test_copy_src_tree_handles_invalid_build_info_json(
+    mock_walk_files: MagicMock,
+    mock_iter_components: MagicMock,
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test copy_src_tree handles invalid build_info.json gracefully."""
+    # 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()
+
+    # Create 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
+    build_info_h_path = esphome_core_path / "build_info_data.h"
+    build_info_h_path.write_text("// old build_info_data.h")
+
+    # Setup mocks
+    mock_core.relative_src_path.side_effect = lambda *args: src_path.joinpath(*args)
+    mock_core.relative_build_path.side_effect = lambda *args: build_path.joinpath(*args)
+    mock_core.defines = []
+    mock_core.config_hash = 0xDEADBEEF
+    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_build_info_timestamp_behavior(
+    mock_walk_files: MagicMock,
+    mock_iter_components: MagicMock,
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test build_info behaviour: regenerated on change, preserved when unchanged."""
+    # Setup directory structure
+    src_path = tmp_path / "src"
+    src_path.mkdir()
+    esphome_core_path = src_path / "esphome" / "core"
+    esphome_core_path.mkdir(parents=True)
+    esphome_components_path = src_path / "esphome" / "components"
+    esphome_components_path.mkdir(parents=True)
+    build_path = tmp_path / "build"
+    build_path.mkdir()
+
+    # Create a source file
+    source_file = tmp_path / "source" / "test.cpp"
+    source_file.parent.mkdir()
+    source_file.write_text("// version 1")
+
+    # Create destination file in build tree
+    dest_file = esphome_components_path / "test.cpp"
+
+    # Create mock FileResource
+    @dataclass(frozen=True)
+    class MockFileResource:
+        package: str
+        resource: str
+        _path: Path
+
+        @contextmanager
+        def path(self):
+            yield self._path
+
+    mock_resources = [
+        MockFileResource(
+            package="esphome.components",
+            resource="test.cpp",
+            _path=source_file,
+        ),
+    ]
+
+    mock_component = MagicMock()
+    mock_component.resources = mock_resources
+
+    # Setup mocks
+    mock_core.relative_src_path.side_effect = lambda *args: src_path.joinpath(*args)
+    mock_core.relative_build_path.side_effect = lambda *args: build_path.joinpath(*args)
+    mock_core.defines = []
+    mock_core.config_hash = 0xDEADBEEF
+    mock_core.target_platform = "test_platform"
+    mock_core.config = {}
+    mock_iter_components.return_value = [("test", mock_component)]
+
+    build_info_json_path = build_path / "build_info.json"
+
+    # First run: initial setup, should create build_info
+    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()
+
+    # Manually set an old timestamp for testing
+    old_timestamp = 1700000000
+    old_timestamp_str = "2023-11-14 22:13:20 +0000"
+    build_info_json_path.write_text(
+        json.dumps(
+            {
+                "config_hash": 0xDEADBEEF,
+                "build_time": old_timestamp,
+                "build_time_str": old_timestamp_str,
+                "esphome_version": "2025.1.0-dev",
+            }
+        )
+    )
+
+    # Second run: no changes, should NOT regenerate build_info
+    mock_walk_files.return_value = [str(dest_file)]
+    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()
+
+    second_json = json.loads(build_info_json_path.read_text())
+    second_timestamp = second_json["build_time"]
+
+    # Verify timestamp was NOT changed
+    assert second_timestamp == old_timestamp, (
+        f"build_info should not be regenerated when no files change: "
+        f"{old_timestamp} != {second_timestamp}"
+    )
+
+    # Third run: change source file, should regenerate build_info with new timestamp
+    source_file.write_text("// version 2")
+    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()
+
+    third_json = json.loads(build_info_json_path.read_text())
+    third_timestamp = third_json["build_time"]
+
+    # Verify timestamp WAS changed
+    assert third_timestamp != old_timestamp, (
+        f"build_info should be regenerated when source file changes: "
+        f"{old_timestamp} == {third_timestamp}"
+    )
+    assert third_timestamp > old_timestamp
+
+
+@patch("esphome.writer.CORE")
+@patch("esphome.writer.iter_components")
+@patch("esphome.writer.walk_files")
+def test_copy_src_tree_detects_removed_source_file(
+    mock_walk_files: MagicMock,
+    mock_iter_components: MagicMock,
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test copy_src_tree detects when a non-generated source file is removed."""
+    # Setup directory structure
+    src_path = tmp_path / "src"
+    src_path.mkdir()
+    esphome_components_path = src_path / "esphome" / "components"
+    esphome_components_path.mkdir(parents=True)
+    build_path = tmp_path / "build"
+    build_path.mkdir()
+
+    # Create an existing source file in the build tree
+    existing_file = esphome_components_path / "test.cpp"
+    existing_file.write_text("// test file")
+
+    # Setup mocks - no components, so the file should be removed
+    mock_core.relative_src_path.side_effect = lambda *args: src_path.joinpath(*args)
+    mock_core.relative_build_path.side_effect = lambda *args: build_path.joinpath(*args)
+    mock_core.defines = []
+    mock_core.config_hash = 0xDEADBEEF
+    mock_core.target_platform = "test_platform"
+    mock_core.config = {}
+    mock_iter_components.return_value = []  # No components = file should be removed
+    mock_walk_files.return_value = [str(existing_file)]
+
+    # Create existing build_info.json
+    build_info_json_path = build_path / "build_info.json"
+    old_timestamp = 1700000000
+    build_info_json_path.write_text(
+        json.dumps(
+            {
+                "config_hash": 0xDEADBEEF,
+                "build_time": old_timestamp,
+                "build_time_str": "2023-11-14 22:13:20 +0000",
+                "esphome_version": "2025.1.0-dev",
+            }
+        )
+    )
+
+    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 file was removed
+    assert not existing_file.exists()
+
+    # Verify build_info was regenerated due to source file removal
+    new_json = json.loads(build_info_json_path.read_text())
+    assert new_json["build_time"] != old_timestamp
+
+
+@patch("esphome.writer.CORE")
+@patch("esphome.writer.iter_components")
+@patch("esphome.writer.walk_files")
+def test_copy_src_tree_ignores_removed_generated_file(
+    mock_walk_files: MagicMock,
+    mock_iter_components: MagicMock,
+    mock_core: MagicMock,
+    tmp_path: Path,
+) -> None:
+    """Test copy_src_tree doesn't mark sources_changed when only generated file removed."""
+    # 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()
+
+    # Create existing build_info_data.h (a generated file)
+    build_info_h = esphome_core_path / "build_info_data.h"
+    build_info_h.write_text("// old generated file")
+
+    # Setup mocks
+    mock_core.relative_src_path.side_effect = lambda *args: src_path.joinpath(*args)
+    mock_core.relative_build_path.side_effect = lambda *args: build_path.joinpath(*args)
+    mock_core.defines = []
+    mock_core.config_hash = 0xDEADBEEF
+    mock_core.target_platform = "test_platform"
+    mock_core.config = {}
+    mock_iter_components.return_value = []
+    # walk_files returns the generated file, but it's not in source_files_copy
+    mock_walk_files.return_value = [str(build_info_h)]
+
+    # Create existing build_info.json with old timestamp
+    build_info_json_path = build_path / "build_info.json"
+    old_timestamp = 1700000000
+    build_info_json_path.write_text(
+        json.dumps(
+            {
+                "config_hash": 0xDEADBEEF,
+                "build_time": old_timestamp,
+                "build_time_str": "2023-11-14 22:13:20 +0000",
+                "esphome_version": "2025.1.0-dev",
+            }
+        )
+    )
+
+    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_data.h was regenerated (not removed)
+    assert build_info_h.exists()
+
+    # Note: build_info.json will have a new timestamp because get_build_info()
+    # always returns current time. The key test is that the old build_info_data.h
+    # file was removed and regenerated, not that it triggered sources_changed.
+    new_json = json.loads(build_info_json_path.read_text())
+    assert new_json["config_hash"] == 0xDEADBEEF