Repository: psf/black
File: src/black/__init__.py (Python)

Code before:

def gen_python_files(
    paths: Iterable[Path],
    root: Path,
    include: Optional[Pattern[str]],
    exclude: Pattern[str],
    extend_exclude: Optional[Pattern[str]],
    force_exclude: Optional[Pattern[str]],
    report: "Report",
    gitignore: Optional[PathSpec],
) -> Iterator[Path]:
    """Generate all files under `path` whose paths are not excluded by the
    `exclude_regex`, `extend_exclude`, or `force_exclude` regexes,
    but are included by the `include` regex.

    Symbolic links pointing outside of the `root` directory are ignored.

    `report` is where output about exclusions goes.
    """
    assert root.is_absolute(), f"INTERNAL ERROR: `root` must be absolute but is {root}"
    for child in paths:
        normalized_path = normalize_path_maybe_ignore(child, root, report)
        if normalized_path is None:
            continue

        # First ignore files matching .gitignore
        if gitignore is not None and gitignore.match_file(normalized_path):
            report.path_ignored(child, "matches the .gitignore file content")
            continue

        # Then ignore with `--exclude` `--extend-exclude` and `--force-exclude` options.
        normalized_path = "/" + normalized_path
        if child.is_dir():
            normalized_path += "/"

        if path_is_excluded(normalized_path, exclude):
            report.path_ignored(child, "matches the --exclude regular expression")
            continue

        if path_is_excluded(normalized_path, extend_exclude):
            report.path_ignored(
                child, "matches the --extend-exclude regular expression"
            )
            continue

        if path_is_excluded(normalized_path, force_exclude):
            report.path_ignored(child, "matches the --force-exclude regular expression")
            continue

        if child.is_dir():
            yield from gen_python_files(

Review comment (suggestion):
Maybe? I don't care, but adding / modifying some comments to make reading the code a little easier seems like a good alternative to the callable idea. Wouldn't mind leaving this comment alone.

```suggestion
        # First ignore files matching .gitignore (unless it's been overridden)
```

Code after:
    return normalized_path


def path_is_excluded(
    normalized_path: str,
    pattern: Optional[Pattern[str]],
) -> bool:
    match = pattern.search(normalized_path) if pattern else None
    return bool(match and match.group(0))


def gen_python_files(
    paths: Iterable[Path],
    root: Path,
    include: Pattern[str],
    exclude: Pattern[str],
    extend_exclude: Optional[Pattern[str]],
    force_exclude: Optional[Pattern[str]],
    report: "Report",
    gitignore: Optional[PathSpec],
) -> Iterator[Path]:
    """Generate all files under `path` whose paths are not excluded by the
    `exclude_regex`, `extend_exclude`, or `force_exclude` regexes,
    but are included by the `include` regex.

    Symbolic links pointing outside of the `root` directory are ignored.

    `report` is where output about exclusions goes.
    """
    assert root.is_absolute(), f"INTERNAL ERROR: `root` must be absolute but is {root}"
    for child in paths:
        normalized_path = normalize_path_maybe_ignore(child, root, report)
        if normalized_path is None:
            continue

        # First ignore files matching .gitignore, if passed
        if gitignore is not None and gitignore.match_file(normalized_path):
            report.path_ignored(child, "matches the .gitignore file content")
            continue

        # Then ignore with `--exclude` `--extend-exclude` and `--force-exclude` options.
        normalized_path = "/" + normalized_path
        if child.is_dir():
            normalized_path += "/"

        if path_is_excluded(normalized_path, exclude):
            report.path_ignored(child, "matches the --exclude regular expression")
            continue

        if path_is_excluded(normalized_path, extend_exclude):
            report.path_ignored(