# Source code for _pytest.recwarn

    """Record warnings during test function execution."""
    import re
    import warnings
    from pprint import pformat
    from types import TracebackType
    from typing import Any
    from typing import Callable
    from typing import Generator
    from typing import Iterator
    from typing import List
    from typing import Optional
    from typing import Pattern
    from typing import Tuple
    from typing import Type
    from typing import TypeVar
    from typing import Union

    from _pytest.compat import final
    from _pytest.compat import overload
    from _pytest.deprecated import check_ispytest
    from _pytest.deprecated import WARNS_NONE_ARG
    from _pytest.fixtures import fixture
    from _pytest.outcomes import fail

    T = TypeVar("T")

    @fixture
    def recwarn() -> Generator["WarningsRecorder", None, None]:
        """Return a :class:`WarningsRecorder` instance that records all warnings emitted by test functions.

        See https://docs.pytest.org/en/latest/how-to/capture-warnings.html for information
        on warning categories.
        """
        wrec = WarningsRecorder(_ispytest=True)
        with wrec:
            warnings.simplefilter("default")
            yield wrec

    @overload
    def deprecated_call(
        *, match: Optional[Union[str, Pattern[str]]] = ...
    ) -> "WarningsRecorder":
        ...

    @overload
    def deprecated_call(  # noqa: F811
        func: Callable[..., T], *args: Any, **kwargs: Any
    ) -> T:
        ...

    def deprecated_call(  # noqa: F811
        func: Optional[Callable[..., Any]] = None, *args: Any, **kwargs: Any
    ) -> Union["WarningsRecorder", Any]:
        """Assert that code produces a ``DeprecationWarning`` or ``PendingDeprecationWarning``.

        This function can be used as a context manager::

            >>> import warnings
            >>> def api_call_v2():
            ...     warnings.warn('use v3 of this api', DeprecationWarning)
            ...     return 200

            >>> import pytest
            >>> with pytest.deprecated_call():
            ...    assert api_call_v2() == 200

        It can also be used by passing a function and ``*args`` and ``**kwargs``,
        in which case it will ensure calling ``func(*args, **kwargs)`` produces one of
        the warnings types above. The return value is the return value of the function.

        In the context manager form you may use the keyword argument ``match`` to assert
        that the warning matches a text or regex.

        The context manager produces a list of :class:`warnings.WarningMessage` objects,
        one for each warning raised.
        """
        __tracebackhide__ = True
        if func is not None:
            args = (func,) + args
        return warns((DeprecationWarning, PendingDeprecationWarning), *args, **kwargs)

    @overload
    def warns(
        expected_warning: Union[Type[Warning], Tuple[Type[Warning], ...]] = ...,
        *,
        match: Optional[Union[str, Pattern[str]]] = ...,
    ) -> "WarningsChecker":
        ...

    @overload
    def warns(  # noqa: F811
        expected_warning: Union[Type[Warning], Tuple[Type[Warning], ...]],
        func: Callable[..., T],
        *args: Any,
        **kwargs: Any,
    ) -> T:
        ...

    def warns(  # noqa: F811
        expected_warning: Union[Type[Warning], Tuple[Type[Warning], ...]] = Warning,
        *args: Any,
        match: Optional[Union[str, Pattern[str]]] = None,
        **kwargs: Any,
    ) -> Union["WarningsChecker", Any]:
        r"""Assert that code raises a particular class of warning.

        Specifically, the parameter ``expected_warning`` can be a warning class or sequence
        of warning classes, and the code inside the ``with`` block must issue at least one
        warning of that class or classes.

        This helper produces a list of :class:`warnings.WarningMessage` objects, one for
        each warning raised (regardless of whether it is an ``expected_warning`` or not).

        This function can be used as a context manager, which will capture all the raised
        warnings inside it::

            >>> import pytest
            >>> with pytest.warns(RuntimeWarning):
            ...    warnings.warn("my warning", RuntimeWarning)

        In the context manager form you may use the keyword argument ``match`` to assert
        that the warning matches a text or regex::

            >>> with pytest.warns(UserWarning, match='must be 0 or None'):
            ...     warnings.warn("value must be 0 or None", UserWarning)

            >>> with pytest.warns(UserWarning, match=r'must be \d+$'):
            ...     warnings.warn("value must be 42", UserWarning)

            >>> with pytest.warns(UserWarning, match=r'must be \d+$'):
            ...     warnings.warn("this is not here", UserWarning)
            Traceback (most recent call last):
              ...
            Failed: DID NOT WARN. No warnings of type ...UserWarning... were emitted...

        **Using with** ``pytest.mark.parametrize``

        When using :ref:`pytest.mark.parametrize ref` it is possible to parametrize tests
        such that some runs raise a warning and others do not.

        This could be achieved in the same way as with exceptions, see
        :ref:`parametrizing_conditional_raising` for an example.

        """
        __tracebackhide__ = True
        if not args:
            if kwargs:
                argnames = ", ".join(sorted(kwargs))
                raise TypeError(
                    f"Unexpected keyword arguments passed to pytest.warns: {argnames}"
                    "\nUse context-manager form instead?"
                )
            return WarningsChecker(expected_warning, match_expr=match, _ispytest=True)
        else:
            func = args[0]
            if not callable(func):
                raise TypeError(f"{func!r} object (type: {type(func)}) must be callable")
            with WarningsChecker(expected_warning, _ispytest=True):
                return func(*args[1:], **kwargs)

    class WarningsRecorder(warnings.catch_warnings):  # type:ignore[type-arg]
        """A context manager to record raised warnings.

        Each recorded warning is an instance of :class:`warnings.WarningMessage`.

        Adapted from `warnings.catch_warnings`.

        .. note::
            ``DeprecationWarning`` and ``PendingDeprecationWarning`` are treated
            differently; see :ref:`ensuring_function_triggers`.

        """

        def __init__(self, *, _ispytest: bool = False) -> None:
            check_ispytest(_ispytest)
            # Type ignored due to the way typeshed handles warnings.catch_warnings.
            super().__init__(record=True)  # type: ignore[call-arg]
            self._entered = False
            self._list: List[warnings.WarningMessage] = []

        @property
        def list(self) -> List["warnings.WarningMessage"]:
            """The list of recorded warnings."""
            return self._list

        def __getitem__(self, i: int) -> "warnings.WarningMessage":
            """Get a recorded warning by index."""
            return self._list[i]

        def __iter__(self) -> Iterator["warnings.WarningMessage"]:
            """Iterate through the recorded warnings."""
            return iter(self._list)

        def __len__(self) -> int:
            """The number of recorded warnings."""
            return len(self._list)

        def pop(self, cls: Type[Warning] = Warning) -> "warnings.WarningMessage":
            """Pop the first recorded warning, raise exception if not exists."""
            for i, w in enumerate(self._list):
                if issubclass(w.category, cls):
                    return self._list.pop(i)
            __tracebackhide__ = True
            raise AssertionError(f"{cls!r} not found in warning list")

        def clear(self) -> None:
            """Clear the list of recorded warnings."""
            self._list[:] = []

        # Type ignored because it doesn't exactly warnings.catch_warnings.__enter__
        # -- it returns a List but we only emulate one.
        def __enter__(self) -> "WarningsRecorder":  # type: ignore
            if self._entered:
                __tracebackhide__ = True
                raise RuntimeError(f"Cannot enter {self!r} twice")
            _list = super().__enter__()
            # record=True means it's None.
            assert _list is not None
            self._list = _list
            warnings.simplefilter("always")
            return self

        def __exit__(
            self,
            exc_type: Optional[Type[BaseException]],
            exc_val: Optional[BaseException],
            exc_tb: Optional[TracebackType],
        ) -> None:
            if not self._entered:
                __tracebackhide__ = True
                raise RuntimeError(f"Cannot exit {self!r} without entering first")

            super().__exit__(exc_type, exc_val, exc_tb)

            # Built-in catch_warnings does not reset entered state so we do it
            # manually here for this context manager to become reusable.
            self._entered = False

    @final
    class WarningsChecker(WarningsRecorder):
        def __init__(
            self,
            expected_warning: Optional[
                Union[Type[Warning], Tuple[Type[Warning], ...]]
            ] = Warning,
            match_expr: Optional[Union[str, Pattern[str]]] = None,
            *,
            _ispytest: bool = False,
        ) -> None:
            check_ispytest(_ispytest)
            super().__init__(_ispytest=True)

            msg = "exceptions must be derived from Warning, not %s"
            if expected_warning is None:
                warnings.warn(WARNS_NONE_ARG, stacklevel=4)
                expected_warning_tup = None
            elif isinstance(expected_warning, tuple):
                for exc in expected_warning:
                    if not issubclass(exc, Warning):
                        raise TypeError(msg % type(exc))
                expected_warning_tup = expected_warning
            elif issubclass(expected_warning, Warning):
                expected_warning_tup = (expected_warning,)
            else:
                raise TypeError(msg % type(expected_warning))

            self.expected_warning = expected_warning_tup
            self.match_expr = match_expr

        def __exit__(
            self,
            exc_type: Optional[Type[BaseException]],
            exc_val: Optional[BaseException],
            exc_tb: Optional[TracebackType],
        ) -> None:
            super().__exit__(exc_type, exc_val, exc_tb)

            __tracebackhide__ = True

            def found_str():
                return pformat([record.message for record in self], indent=2)

            # only check if we're not currently handling an exception
            if exc_type is None and exc_val is None and exc_tb is None:
                if self.expected_warning is not None:
                    if not any(issubclass(r.category, self.expected_warning) for r in self):
                        __tracebackhide__ = True
                        fail(
                            f"DID NOT WARN. No warnings of type {self.expected_warning} were emitted.\n"
                            f"The list of emitted warnings is: {found_str()}."
                        )
                    elif self.match_expr is not None:
                        for r in self:
                            if issubclass(r.category, self.expected_warning):
                                if re.compile(self.match_expr).search(str(r.message)):
                                    break
                        else:
                            fail(
                                f"""\
    DID NOT WARN. No warnings of type {self.expected_warning} matching the regex were emitted.
     Regex: {self.match_expr}
     Emitted warnings: {found_str()}"""
                            )