Fix compatibility with Twisted 25

.github/workflows/test.yml

@@ -54,7 +54,9 @@ jobs:
       fail-fast: false
       matrix:
         name: [
-          "windows-py39-unittestextras",
+          "windows-py39-unittest-asynctest",
+          "windows-py39-unittest-twisted24",
+          "windows-py39-unittest-twisted25",
           "windows-py39-pluggy",
           "windows-py39-xdist",
           "windows-py310",
@@ -63,6 +65,9 @@ jobs:
           "windows-py313",
           "windows-py314",
 
+          "ubuntu-py39-unittest-asynctest",
+          "ubuntu-py39-unittest-twisted24",
+          "ubuntu-py39-unittest-twisted25",
           "ubuntu-py39-lsof-numpy-pexpect",
           "ubuntu-py39-pluggy",
           "ubuntu-py39-freeze",
@@ -85,10 +90,23 @@ jobs:
         ]
 
         include:
-          - name: "windows-py39-unittestextras"
+          # Use separate jobs for different unittest flavors (twisted, asynctest) to ensure proper coverage.
+          - name: "windows-py39-unittest-asynctest"
             python: "3.9"
             os: windows-latest
-            tox_env: "py39-unittestextras"
+            tox_env: "py39-asynctest"
+            use_coverage: true
+
+          - name: "windows-py39-unittest-twisted24"
+            python: "3.9"
+            os: windows-latest
+            tox_env: "py39-twisted24"
+            use_coverage: true
+
+          - name: "windows-py39-unittest-twisted25"
+            python: "3.9"
+            os: windows-latest
+            tox_env: "py39-twisted25"
             use_coverage: true
 
           - name: "windows-py39-pluggy"
@@ -126,6 +144,25 @@ jobs:
             os: windows-latest
             tox_env: "py314"
 
+          # Use separate jobs for different unittest flavors (twisted, asynctest) to ensure proper coverage.
+          - name: "ubuntu-py39-unittest-asynctest"
+            python: "3.9"
+            os: ubuntu-latest
+            tox_env: "py39-asynctest"
+            use_coverage: true
+
+          - name: "ubuntu-py39-unittest-twisted24"
+            python: "3.9"
+            os: ubuntu-latest
+            tox_env: "py39-twisted24"
+            use_coverage: true
+
+          - name: "ubuntu-py39-unittest-twisted25"
+            python: "3.9"
+            os: ubuntu-latest
+            tox_env: "py39-twisted25"
+            use_coverage: true
+
           - name: "ubuntu-py39-lsof-numpy-pexpect"
             python: "3.9"
             os: ubuntu-latest

changelog/13497.bugfix.rst

@@ -0,0 +1 @@
+Fixed compatibility with ``Twisted 25+``.

src/_pytest/unittest.py

@@ -6,18 +6,21 @@
 from collections.abc import Callable
 from collections.abc import Generator
 from collections.abc import Iterable
+from collections.abc import Iterator
+from enum import auto
+from enum import Enum
 import inspect
 import sys
 import traceback
 import types
-from typing import Any
 from typing import TYPE_CHECKING
 from typing import Union
 
 import _pytest._code
 from _pytest.compat import is_async_function
 from _pytest.config import hookimpl
 from _pytest.fixtures import FixtureRequest
+from _pytest.monkeypatch import MonkeyPatch
 from _pytest.nodes import Collector
 from _pytest.nodes import Item
 from _pytest.outcomes import exit
@@ -228,8 +231,7 @@ def startTest(self, testcase: unittest.TestCase) -> None:
         pass
 
     def _addexcinfo(self, rawexcinfo: _SysExcInfoType) -> None:
-        # Unwrap potential exception info (see twisted trial support below).
-        rawexcinfo = getattr(rawexcinfo, "_rawexcinfo", rawexcinfo)
+        rawexcinfo = _handle_twisted_exc_info(rawexcinfo)
         try:
             excinfo = _pytest._code.ExceptionInfo[BaseException].from_exc_info(
                 rawexcinfo  # type: ignore[arg-type]
@@ -373,49 +375,130 @@ def pytest_runtest_makereport(item: Item, call: CallInfo[None]) -> None:
                 pass
 
 
-# Twisted trial support.
-classImplements_has_run = False
+def _is_skipped(obj) -> bool:
+    """Return True if the given object has been marked with @unittest.skip."""
+    return bool(getattr(obj, "__unittest_skip__", False))
+
+
+def pytest_configure() -> None:
+    """Register the TestCaseFunction class as an IReporter if twisted.trial is available."""
+    if _get_twisted_version() is not TwistedVersion.NotInstalled:
+        from twisted.trial.itrial import IReporter
+        from zope.interface import classImplements
+
+        classImplements(TestCaseFunction, IReporter)
+
+
+class TwistedVersion(Enum):
+    """
+    The Twisted version installed in the environment.
+
+    We have different workarounds in place for different versions of Twisted.
+    """
+
+    # Twisted version 24 or prior.
+    Version24 = auto()
+    # Twisted version 25 or later.
+    Version25 = auto()
+    # Twisted version is not available.
+    NotInstalled = auto()
+
+
+def _get_twisted_version() -> TwistedVersion:
+    # We need to check if "twisted.trial.unittest" is specifically present in sys.modules.
+    # This is because we intend to integrate with Trial only when it's actively running
+    # the test suite, but not needed when only other Twisted components are in use.
+    if "twisted.trial.unittest" not in sys.modules:
+        return TwistedVersion.NotInstalled
+
+    import importlib.metadata
+
+    import packaging.version
+
+    version_str = importlib.metadata.version("twisted")
+    version = packaging.version.parse(version_str)
+    if version.major <= 24:
+        return TwistedVersion.Version24
+    else:
+        return TwistedVersion.Version25
+
+
+# Name of the attribute in `twisted.python.Failure` instances that stores
+# the `sys.exc_info()` tuple.
+# See twisted.trial support in `pytest_runtest_protocol`.
+TWISTED_RAW_EXCINFO_ATTR = "_twisted_raw_excinfo"
 
 
 @hookimpl(wrapper=True)
-def pytest_runtest_protocol(item: Item) -> Generator[None, object, object]:
-    if isinstance(item, TestCaseFunction) and "twisted.trial.unittest" in sys.modules:
-        ut: Any = sys.modules["twisted.python.failure"]
-        global classImplements_has_run
-        Failure__init__ = ut.Failure.__init__
-        if not classImplements_has_run:
-            from twisted.trial.itrial import IReporter
-            from zope.interface import classImplements
-
-            classImplements(TestCaseFunction, IReporter)
-            classImplements_has_run = True
-
-        def excstore(
+def pytest_runtest_protocol(item: Item) -> Iterator[None]:
+    if _get_twisted_version() is TwistedVersion.Version24:
+        import twisted.python.failure as ut
+
+        # Monkeypatch `Failure.__init__` to store the raw exception info.
+        original__init__ = ut.Failure.__init__
+
+        def store_raw_exception_info(
             self, exc_value=None, exc_type=None, exc_tb=None, captureVars=None
-        ):
+        ):  # pragma: no cover
             if exc_value is None:
-                self._rawexcinfo = sys.exc_info()
+                raw_exc_info = sys.exc_info()
             else:
                 if exc_type is None:
                     exc_type = type(exc_value)
-                self._rawexcinfo = (exc_type, exc_value, exc_tb)
+                if exc_tb is None:
+                    exc_tb = sys.exc_info()[2]
+                raw_exc_info = (exc_type, exc_value, exc_tb)
+            setattr(self, TWISTED_RAW_EXCINFO_ATTR, tuple(raw_exc_info))
             try:
-                Failure__init__(
+                original__init__(
                     self, exc_value, exc_type, exc_tb, captureVars=captureVars
                 )
-            except TypeError:
-                Failure__init__(self, exc_value, exc_type, exc_tb)
+            except TypeError:  # pragma: no cover
+                original__init__(self, exc_value, exc_type, exc_tb)
 
-        ut.Failure.__init__ = excstore
-        try:
-            res = yield
-        finally:
-            ut.Failure.__init__ = Failure__init__
+        with MonkeyPatch.context() as patcher:
+            patcher.setattr(ut.Failure, "__init__", store_raw_exception_info)
+            return (yield)
     else:
-        res = yield
-    return res
-
-
-def _is_skipped(obj) -> bool:
-    """Return True if the given object has been marked with @unittest.skip."""
-    return bool(getattr(obj, "__unittest_skip__", False))
+        return (yield)
+
+
+def _handle_twisted_exc_info(
+    rawexcinfo: _SysExcInfoType | BaseException,
+) -> _SysExcInfoType:
+    """
+    Twisted passes a custom Failure instance to `addError()` instead of using `sys.exc_info()`.
+    Therefore, if `rawexcinfo` is a `Failure` instance, convert it into the equivalent `sys.exc_info()` tuple
+    as expected by pytest.
+    """
+    twisted_version = _get_twisted_version()
+    if twisted_version is TwistedVersion.NotInstalled:
+        # Unfortunately, because we cannot import `twisted.python.failure` at the top of the file
+        # and use it in the signature, we need to use `type:ignore` here because we cannot narrow
+        # the type properly in the `if` statement above.
+        return rawexcinfo  # type:ignore[return-value]
+    elif twisted_version is TwistedVersion.Version24:
+        # Twisted calls addError() passing its own classes (like `twisted.python.Failure`), which violates
+        # the `addError()` signature, so we extract the original `sys.exc_info()` tuple which is stored
+        # in the object.
+        if hasattr(rawexcinfo, TWISTED_RAW_EXCINFO_ATTR):
+            saved_exc_info = getattr(rawexcinfo, TWISTED_RAW_EXCINFO_ATTR)
+            # Delete the attribute from the original object to avoid leaks.
+            delattr(rawexcinfo, TWISTED_RAW_EXCINFO_ATTR)
+            return saved_exc_info  # type:ignore[no-any-return]
+        return rawexcinfo  # type:ignore[return-value]
+    elif twisted_version is TwistedVersion.Version25:
+        if isinstance(rawexcinfo, BaseException):
+            import twisted.python.failure
+
+            if isinstance(rawexcinfo, twisted.python.failure.Failure):
+                tb = rawexcinfo.__traceback__
+                if tb is None:
+                    tb = sys.exc_info()[2]
+                return type(rawexcinfo.value), rawexcinfo.value, tb
+
+        return rawexcinfo  # type:ignore[return-value]
+    else:
+        # Ideally we would use assert_never() here, but it is not available in all Python versions
+        # we support, plus we do not require `type_extensions` currently.
+        assert False, f"Unexpected Twisted version: {twisted_version}"

tox.ini

@@ -11,7 +11,7 @@ envlist =
     py313
     py314
     pypy3
-    py39-{pexpect,xdist,unittestextras,numpy,pluggymain,pylib}
+    py39-{pexpect,xdist,twisted24,twisted25,asynctest,numpy,pluggymain,pylib}
     doctesting
     doctesting-coverage
     plugins
@@ -36,7 +36,9 @@ description =
     pexpect: against `pexpect`
     pluggymain: against the bleeding edge `pluggy` from Git
     pylib: against `py` lib
-    unittestextras: against the unit test extras
+    twisted24: against the unit test extras with twisted prior to 24.0
+    twisted25: against the unit test extras with twisted 25.0 or later
+    asynctest: against the unit test extras with asynctest
     xdist: with pytest in parallel mode
     under `{basepython}`
     doctesting: including doctests
@@ -51,7 +53,7 @@ passenv =
     TERM
     SETUPTOOLS_SCM_PRETEND_VERSION_FOR_PYTEST
 setenv =
-    _PYTEST_TOX_DEFAULT_POSARGS={env:_PYTEST_TOX_POSARGS_DOCTESTING:} {env:_PYTEST_TOX_POSARGS_LSOF:} {env:_PYTEST_TOX_POSARGS_XDIST:}
+    _PYTEST_TOX_DEFAULT_POSARGS={env:_PYTEST_TOX_POSARGS_DOCTESTING:} {env:_PYTEST_TOX_POSARGS_LSOF:} {env:_PYTEST_TOX_POSARGS_XDIST:} {env:_PYTEST_FILES:}
 
     # See https://docs.python.org/3/library/io.html#io-encoding-warning
     # If we don't enable this, neither can any of our downstream users!
@@ -66,6 +68,12 @@ setenv =
 
     doctesting: _PYTEST_TOX_POSARGS_DOCTESTING=doc/en
 
+    # The configurations below are related only to standard unittest support.
+    # Run only tests from test_unittest.py.
+    asynctest: _PYTEST_FILES=testing/test_unittest.py
+    twisted24: _PYTEST_FILES=testing/test_unittest.py
+    twisted25: _PYTEST_FILES=testing/test_unittest.py
+
     nobyte: PYTHONDONTWRITEBYTECODE=1
 
     lsof: _PYTEST_TOX_POSARGS_LSOF=--lsof
@@ -79,8 +87,9 @@ deps =
     pexpect: pexpect>=4.8.0
     pluggymain: pluggy @ git+https://github.com/pytest-dev/pluggy.git
     pylib: py>=1.8.2
-    unittestextras: twisted
-    unittestextras: asynctest
+    twisted24: twisted<25
+    twisted25: twisted>=25
+    asynctest: asynctest
     xdist: pytest-xdist>=2.1.0
     xdist: -e .
     {env:_PYTEST_TOX_EXTRA_DEP:}