Merge pull request #6758 from bluetech/outcome-exception-callable-2

Use a hack to make typing of pytest.fail.Exception & co work

src/_pytest/main.py

@@ -25,7 +25,7 @@
 from _pytest.config import hookimpl
 from _pytest.config import UsageError
 from _pytest.fixtures import FixtureManager
-from _pytest.outcomes import Exit
+from _pytest.outcomes import exit
 from _pytest.reports import CollectReport
 from _pytest.runner import collect_one_node
 from _pytest.runner import SetupState
@@ -195,10 +195,10 @@ def wrap_session(
             raise
         except Failed:
             session.exitstatus = ExitCode.TESTS_FAILED
-        except (KeyboardInterrupt, Exit):
+        except (KeyboardInterrupt, exit.Exception):
             excinfo = _pytest._code.ExceptionInfo.from_current()
             exitstatus = ExitCode.INTERRUPTED  # type: Union[int, ExitCode]
-            if isinstance(excinfo.value, Exit):
+            if isinstance(excinfo.value, exit.Exception):
                 if excinfo.value.returncode is not None:
                     exitstatus = excinfo.value.returncode
                 if initstate < 2:
@@ -212,7 +212,7 @@ def wrap_session(
             excinfo = _pytest._code.ExceptionInfo.from_current()
             try:
                 config.notify_exception(excinfo, config.option)
-            except Exit as exc:
+            except exit.Exception as exc:
                 if exc.returncode is not None:
                     session.exitstatus = exc.returncode
                 sys.stderr.write("{}: {}\n".format(type(exc).__name__, exc))
@@ -229,7 +229,7 @@ def wrap_session(
                 config.hook.pytest_sessionfinish(
                     session=session, exitstatus=session.exitstatus
                 )
-            except Exit as exc:
+            except exit.Exception as exc:
                 if exc.returncode is not None:
                     session.exitstatus = exc.returncode
                 sys.stderr.write("{}: {}\n".format(type(exc).__name__, exc))

src/_pytest/nodes.py

@@ -27,6 +27,7 @@
 from _pytest.mark.structures import Mark
 from _pytest.mark.structures import MarkDecorator
 from _pytest.mark.structures import NodeKeywords
+from _pytest.outcomes import fail
 from _pytest.outcomes import Failed
 
 if TYPE_CHECKING:
@@ -314,7 +315,7 @@ def _prunetraceback(self, excinfo):
     def _repr_failure_py(
         self, excinfo: ExceptionInfo[Union[Failed, FixtureLookupError]], style=None
     ) -> Union[str, ReprExceptionInfo, ExceptionChainRepr, FixtureLookupErrorRepr]:
-        if isinstance(excinfo.value, Failed):
+        if isinstance(excinfo.value, fail.Exception):
             if not excinfo.value.pytrace:
                 return str(excinfo.value)
         if isinstance(excinfo.value, FixtureLookupError):

src/_pytest/outcomes.py

@@ -4,14 +4,26 @@
 """
 import sys
 from typing import Any
+from typing import Callable
+from typing import cast
 from typing import Optional
+from typing import TypeVar
 
 from packaging.version import Version
 
 TYPE_CHECKING = False  # avoid circular import through compat
 
 if TYPE_CHECKING:
     from typing import NoReturn
+    from typing import Type  # noqa: F401 (Used in string type annotation.)
+    from typing_extensions import Protocol
+else:
+    # typing.Protocol is only available starting from Python 3.8. It is also
+    # available from typing_extensions, but we don't want a runtime dependency
+    # on that. So use a dummy runtime implementation.
+    from typing import Generic
+
+    Protocol = Generic
 
 
 class OutcomeException(BaseException):
@@ -73,9 +85,31 @@ def __init__(
         super().__init__(msg)
 
 
+# Elaborate hack to work around https://github.com/python/mypy/issues/2087.
+# Ideally would just be `exit.Exception = Exit` etc.
+
+_F = TypeVar("_F", bound=Callable)
+_ET = TypeVar("_ET", bound="Type[BaseException]")
+
+
+class _WithException(Protocol[_F, _ET]):
+    Exception = None  # type: _ET
+    __call__ = None  # type: _F
+
+
+def _with_exception(exception_type: _ET) -> Callable[[_F], _WithException[_F, _ET]]:
+    def decorate(func: _F) -> _WithException[_F, _ET]:
+        func_with_exception = cast(_WithException[_F, _ET], func)
+        func_with_exception.Exception = exception_type
+        return func_with_exception
+
+    return decorate
+
+
 # exposed helper methods
 
 
+@_with_exception(Exit)
 def exit(msg: str, returncode: Optional[int] = None) -> "NoReturn":
     """
     Exit testing process.
@@ -87,10 +121,7 @@ def exit(msg: str, returncode: Optional[int] = None) -> "NoReturn":
     raise Exit(msg, returncode)
 
 
-# Ignore type because of https://github.com/python/mypy/issues/2087.
-exit.Exception = Exit  # type: ignore
-
-
+@_with_exception(Skipped)
 def skip(msg: str = "", *, allow_module_level: bool = False) -> "NoReturn":
     """
     Skip an executing test with the given message.
@@ -114,10 +145,7 @@ def skip(msg: str = "", *, allow_module_level: bool = False) -> "NoReturn":
     raise Skipped(msg=msg, allow_module_level=allow_module_level)
 
 
-# Ignore type because of https://github.com/python/mypy/issues/2087.
-skip.Exception = Skipped  # type: ignore
-
-
+@_with_exception(Failed)
 def fail(msg: str = "", pytrace: bool = True) -> "NoReturn":
     """
     Explicitly fail an executing test with the given message.
@@ -130,14 +158,11 @@ def fail(msg: str = "", pytrace: bool = True) -> "NoReturn":
     raise Failed(msg=msg, pytrace=pytrace)
 
 
-# Ignore type because of https://github.com/python/mypy/issues/2087.
-fail.Exception = Failed  # type: ignore
-
-
 class XFailed(Failed):
     """ raised from an explicit call to pytest.xfail() """
 
 
+@_with_exception(XFailed)
 def xfail(reason: str = "") -> "NoReturn":
     """
     Imperatively xfail an executing test or setup functions with the given reason.
@@ -152,10 +177,6 @@ def xfail(reason: str = "") -> "NoReturn":
     raise XFailed(reason)
 
 
-# Ignore type because of https://github.com/python/mypy/issues/2087.
-xfail.Exception = XFailed  # type: ignore
-
-
 def importorskip(
     modname: str, minversion: Optional[str] = None, reason: Optional[str] = None
 ) -> Any:

src/_pytest/reports.py

@@ -284,8 +284,7 @@ def from_item_and_call(cls, item, call) -> "TestReport":
             if not isinstance(excinfo, ExceptionInfo):
                 outcome = "failed"
                 longrepr = excinfo
-            # Type ignored -- see comment where skip.Exception is defined.
-            elif excinfo.errisinstance(skip.Exception):  # type: ignore
+            elif excinfo.errisinstance(skip.Exception):
                 outcome = "skipped"
                 r = excinfo._getreprcrash()
                 longrepr = (str(r.path), r.lineno, r.message)

testing/python/collect.py

@@ -904,6 +904,8 @@ def test_skip_simple(self):
             pytest.skip("xxx")
         assert excinfo.traceback[-1].frame.code.name == "skip"
         assert excinfo.traceback[-1].ishidden()
+        assert excinfo.traceback[-2].frame.code.name == "test_skip_simple"
+        assert not excinfo.traceback[-2].ishidden()
 
     def test_traceback_argsetup(self, testdir):
         testdir.makeconftest(

testing/python/metafunc.py

@@ -16,7 +16,7 @@
 import pytest
 from _pytest import fixtures
 from _pytest import python
-from _pytest.outcomes import Failed
+from _pytest.outcomes import fail
 from _pytest.pytester import Testdir
 from _pytest.python import _idval
 
@@ -99,7 +99,7 @@ def gen() -> Iterator[Union[int, None, Exc]]:
             ({"x": 2}, "2"),
         ]
         with pytest.raises(
-            Failed,
+            fail.Exception,
             match=(
                 r"In func: ids must be list of string/float/int/bool, found:"
                 r" Exc\(from_gen\) \(type: <class .*Exc'>\) at index 2"
@@ -113,7 +113,7 @@ def func(x):
 
         metafunc = self.Metafunc(func)
         with pytest.raises(
-            Failed,
+            fail.Exception,
             match=r"parametrize\(\) call in func got an unexpected scope value 'doggy'",
         ):
             metafunc.parametrize("x", [1], scope="doggy")
@@ -126,7 +126,7 @@ def func(request):
 
         metafunc = self.Metafunc(func)
         with pytest.raises(
-            Failed,
+            fail.Exception,
             match=r"'request' is a reserved name and cannot be used in @pytest.mark.parametrize",
         ):
             metafunc.parametrize("request", [1])
@@ -205,10 +205,10 @@ def func(x, y):
 
         metafunc = self.Metafunc(func)
 
-        with pytest.raises(Failed):
+        with pytest.raises(fail.Exception):
             metafunc.parametrize("x", [1, 2], ids=["basic"])
 
-        with pytest.raises(Failed):
+        with pytest.raises(fail.Exception):
             metafunc.parametrize(
                 ("x", "y"), [("abc", "def"), ("ghi", "jkl")], ids=["one"]
             )
@@ -689,7 +689,7 @@ def func(x, y):
 
         metafunc = self.Metafunc(func)
         with pytest.raises(
-            Failed,
+            fail.Exception,
             match="In func: expected Sequence or boolean for indirect, got dict",
         ):
             metafunc.parametrize("x, y", [("a", "b")], indirect={})  # type: ignore[arg-type] # noqa: F821
@@ -730,7 +730,7 @@ def func(x, y):
             pass
 
         metafunc = self.Metafunc(func)
-        with pytest.raises(Failed):
+        with pytest.raises(fail.Exception):
             metafunc.parametrize("x, y", [("a", "b")], indirect=["x", "z"])
 
     def test_parametrize_uses_no_fixture_error_indirect_false(

testing/test_pytester.py

@@ -10,7 +10,6 @@
 import pytest
 from _pytest.config import ExitCode
 from _pytest.config import PytestPluginManager
-from _pytest.outcomes import Failed
 from _pytest.pytester import CwdSnapshot
 from _pytest.pytester import HookRecorder
 from _pytest.pytester import LineMatcher
@@ -171,7 +170,7 @@ def test_hookrecorder_basic(holder) -> None:
     call = rec.popcall("pytest_xyz")
     assert call.arg == 123
     assert call._name == "pytest_xyz"
-    pytest.raises(Failed, rec.popcall, "abc")
+    pytest.raises(pytest.fail.Exception, rec.popcall, "abc")
     pm.hook.pytest_xyz_noarg()
     call = rec.popcall("pytest_xyz_noarg")
     assert call._name == "pytest_xyz_noarg"
@@ -482,7 +481,7 @@ def test_linematcher_with_nonlist() -> None:
 
 def test_linematcher_match_failure() -> None:
     lm = LineMatcher(["foo", "foo", "bar"])
-    with pytest.raises(Failed) as e:
+    with pytest.raises(pytest.fail.Exception) as e:
         lm.fnmatch_lines(["foo", "f*", "baz"])
     assert e.value.msg is not None
     assert e.value.msg.splitlines() == [
@@ -495,7 +494,7 @@ def test_linematcher_match_failure() -> None:
     ]
 
     lm = LineMatcher(["foo", "foo", "bar"])
-    with pytest.raises(Failed) as e:
+    with pytest.raises(pytest.fail.Exception) as e:
         lm.re_match_lines(["foo", "^f.*", "baz"])
     assert e.value.msg is not None
     assert e.value.msg.splitlines() == [
@@ -550,7 +549,7 @@ def test_linematcher_no_matching(function) -> None:
 
     # check the function twice to ensure we don't accumulate the internal buffer
     for i in range(2):
-        with pytest.raises(Failed) as e:
+        with pytest.raises(pytest.fail.Exception) as e:
             func = getattr(lm, function)
             func(good_pattern)
         obtained = str(e.value).splitlines()
@@ -580,7 +579,7 @@ def test_linematcher_no_matching(function) -> None:
 def test_linematcher_no_matching_after_match() -> None:
     lm = LineMatcher(["1", "2", "3"])
     lm.fnmatch_lines(["1", "3"])
-    with pytest.raises(Failed) as e:
+    with pytest.raises(pytest.fail.Exception) as e:
         lm.no_fnmatch_line("*")
     assert str(e.value).splitlines() == ["fnmatch: '*'", "   with: '1'"]