Function _warnings_warn

lib/sqlalchemy/util/langhelpers.py:1924–1976

(
    message: Union[str, Warning],
    category: Optional[Type[Warning]] = None,
    stacklevel: int = 2,
)

def _warnings_warn(
    message: Union[str, Warning],
    category: Optional[Type[Warning]] = None,
    stacklevel: int = 2,
) -> None:

    if category is None and isinstance(message, Warning):
        category = type(message)

    # adjust the given stacklevel to be outside of SQLAlchemy
    try:
        frame = sys._getframe(stacklevel)
    except ValueError:
        # being called from less than 3 (or given) stacklevels, weird,
        # but don't crash
        stacklevel = 0
    except:
        # _getframe() doesn't work, weird interpreter issue, weird,
        # ok, but don't crash
        stacklevel = 0
    else:
        stacklevel_found = warning_tag_found = False
        while frame is not None:
            # using __name__ here requires that we have __name__ in the
            # __globals__ of the decorated string functions we make also.
            # we generate this using {"__name__": fn.__module__}
            if not stacklevel_found and not re.match(
                _not_sa_pattern, frame.f_globals.get("__name__", "")
            ):
                # stop incrementing stack level if an out-of-SQLA line
                # were found.
                stacklevel_found = True

                # however, for the warning tag thing, we have to keep
                # scanning up the whole traceback

            if frame.f_code in _warning_tags:
                warning_tag_found = True
                _suffix, _category = _warning_tags[frame.f_code]
                category = category or _category
                message = f"{message} ({_suffix})"

            frame = frame.f_back  # type: ignore[assignment]

            if not stacklevel_found:
                stacklevel += 1
            elif stacklevel_found and warning_tag_found:
                break

    if category is not None:
        warnings.warn(message, category, stacklevel=stacklevel + 1)
    else:
        warnings.warn(message, stacklevel=stacklevel + 1)


def only_once(