Method __new__

lib/sqlalchemy/util/langhelpers.py:1689–1717

(
        cls,
        name: str,
        doc: Optional[str] = None,
        canonical: Optional[int] = None,
    )

    _lock = threading.Lock()

    def __new__(
        cls,
        name: str,
        doc: Optional[str] = None,
        canonical: Optional[int] = None,
    ) -> symbol:
        with cls._lock:
            sym = cls.symbols.get(name)
            if sym is None:
                assert isinstance(name, str)
                if canonical is None:
                    canonical = hash(name)
                sym = int.__new__(symbol, canonical)
                sym.name = name
                if doc:
                    sym.__doc__ = doc

                # NOTE: we should ultimately get rid of this global thing,
                # however, currently it is to support pickling.  The best
                # change would be when we are on py3.11 at a minimum, we
                # switch to stdlib enum.IntFlag.
                cls.symbols[name] = sym
            else:
                if canonical and canonical != sym:
                    raise TypeError(
                        f"Can't replace canonical symbol for {name!r} "
                        f"with new int value {canonical}"
                    )
            return sym

    def __reduce__(self):
        return symbol, (self.name, "x", int(self))