Function parse

mypy/fastparse.py:187–272

Parse a source file, without doing any semantic analysis. Return the parse tree. If errors is not provided, raise ParseError on failure. Otherwise, use the errors object to report parse errors.

(
    source: str | bytes,
    fnam: str,
    module: str | None,
    errors: Errors,
    options: Options | None = None,
)

def parse(
    source: str | bytes,
    fnam: str,
    module: str | None,
    errors: Errors,
    options: Options | None = None,
) -> MypyFile:
    """Parse a source file, without doing any semantic analysis.

    Return the parse tree. If errors is not provided, raise ParseError
    on failure. Otherwise, use the errors object to report parse errors.
    """
    ignore_errors = (options is not None and options.ignore_errors) or (
        fnam in errors.ignored_files
    )
    # If errors are ignored, we can drop many function bodies to speed up type checking.
    strip_function_bodies = ignore_errors and (options is None or not options.preserve_asts)

    if options is None:
        options = Options()
    errors.set_file(fnam, module, options=options)
    is_stub_file = fnam.endswith(".pyi")
    if is_stub_file:
        feature_version = defaults.PYTHON3_VERSION[1]
        if options.python_version[0] == 3 and options.python_version[1] > feature_version:
            feature_version = options.python_version[1]
    else:
        assert options.python_version[0] >= 3
        feature_version = options.python_version[1]
    try:
        # Disable
        # - deprecation warnings for 'invalid escape sequence' (Python 3.11 and below)
        # - syntax warnings for 'invalid escape sequence' (3.12+) and 'return in finally' (3.14+)
        with warnings.catch_warnings():
            warnings.filterwarnings("ignore", category=DeprecationWarning)
            warnings.filterwarnings("ignore", category=SyntaxWarning)
            ast = ast3_parse(source, fnam, "exec", feature_version=feature_version)

        tree = ASTConverter(
            options=options,
            is_stub=is_stub_file,
            errors=errors,
            strip_function_bodies=strip_function_bodies,
            path=fnam,
        ).visit(ast)

    except RecursionError as e:
        # For very complex expressions it is possible to hit recursion limit
        # before reaching a leaf node.
        # Should reject at top level instead at bottom, since bottom would already
        # be at the threshold of the recursion limit, and may fail again later.
        # E.G. x1+x2+x3+...+xn -> BinOp(left=BinOp(left=BinOp(left=...
        try:
            # But to prove that is the cause of this particular recursion error,
            # try to walk the tree using builtin visitor
            ast3.NodeVisitor().visit(ast)
        except RecursionError:
            errors.report(