Function build_inner

mypy/build.py:464–564

(
    sources: list[BuildSource],
    options: Options,
    alt_lib_path: str | None,
    flush_errors: Callable[[str | None, list[str], bool], None],
    fscache: FileSystemCache | None,
    stdout: TextIO,
    stderr: TextIO,
    extra_plugins: Sequence[Plugin],
    workers: list[WorkerClient],
    connect_threads: list[Thread],
    metastore: MetadataStore,
)

def build_inner(
    sources: list[BuildSource],
    options: Options,
    alt_lib_path: str | None,
    flush_errors: Callable[[str | None, list[str], bool], None],
    fscache: FileSystemCache | None,
    stdout: TextIO,
    stderr: TextIO,
    extra_plugins: Sequence[Plugin],
    workers: list[WorkerClient],
    connect_threads: list[Thread],
    metastore: MetadataStore,
) -> BuildResult:
    if platform.python_implementation() == "CPython":
        # Run gc less frequently, as otherwise we can spend a large fraction of
        # cpu in gc. This seems the most reasonable place to tune garbage collection.
        gc.set_threshold(200 * 1000, 30, 30)

    data_dir = default_data_dir()
    fscache = fscache or FileSystemCache()

    search_paths = compute_search_paths(sources, options, data_dir, alt_lib_path)

    reports = None
    if options.report_dirs:
        # Import lazily to avoid slowing down startup.
        from mypy.report import Reports

        reports = Reports(data_dir, options.report_dirs)

    source_set = BuildSourceSet(sources)
    cached_read = fscache.read
    error_formatter = None if options.output is None else OUTPUT_CHOICES.get(options.output)
    errors = Errors(
        options,
        read_source=lambda path: read_py_file(path, cached_read),
        error_formatter=error_formatter,
    )
    # Record import errors so that they can be replayed by the workers.
    if workers:
        errors.global_watcher = True
    plugin, snapshot = load_plugins(options, errors, stdout, extra_plugins)

    # Validate error codes after plugins are loaded.
    options.process_error_codes(error_callback=build_error)

    # Construct a build manager object to hold state during the build.
    #
    # Ignore current directory prefix in error messages.
    manager = BuildManager(
        data_dir,
        search_paths,
        ignore_prefix=os.getcwd(),
        source_set=source_set,
        reports=reports,
        options=options,
        version_id=__version__,
        plugin=plugin,