use Contextmanagers to handle StopIteration in generators (pytest-dev#12934)

* prepare example test for stopiteration passover issue

* WIP: use contextmanagers instead of yield from

as it turns out, StopIteration is not transparent on the boundaries of generators

# Conflicts:
#	src/_pytest/threadexception.py
#	src/_pytest/unraisableexception.py

* fixup rebase

* rebase fixup more

* add tests

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* remove hook_exceptions examples - these are tests now

* add changelog

* handle different numbers of ===

* handle different numbers of !!!

---------

Co-authored-by: Thomas Grainger <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 3 people

changelog/12929.bugfix.rst

@@ -0,0 +1 @@
+Handle StopIteration from test cases, setup and teardown correctly.

src/_pytest/logging.py

@@ -809,6 +809,7 @@ def pytest_runtest_logstart(self) -> None:
     def pytest_runtest_logreport(self) -> None:
         self.log_cli_handler.set_when("logreport")
 
+    @contextmanager
     def _runtest_for(self, item: nodes.Item, when: str) -> Generator[None]:
         """Implement the internals of the pytest_runtest_xxx() hooks."""
         with (
@@ -838,20 +839,23 @@ def pytest_runtest_setup(self, item: nodes.Item) -> Generator[None]:
 
         empty: dict[str, list[logging.LogRecord]] = {}
         item.stash[caplog_records_key] = empty
-        yield from self._runtest_for(item, "setup")
+        with self._runtest_for(item, "setup"):
+            yield
 
     @hookimpl(wrapper=True)
     def pytest_runtest_call(self, item: nodes.Item) -> Generator[None]:
         self.log_cli_handler.set_when("call")
 
-        yield from self._runtest_for(item, "call")
+        with self._runtest_for(item, "call"):
+            yield
 
     @hookimpl(wrapper=True)
     def pytest_runtest_teardown(self, item: nodes.Item) -> Generator[None]:
         self.log_cli_handler.set_when("teardown")
 
         try:
-            yield from self._runtest_for(item, "teardown")
+            with self._runtest_for(item, "teardown"):
+                yield
         finally:
             del item.stash[caplog_records_key]
             del item.stash[caplog_handler_key]

testing/acceptance_test.py

@@ -1606,3 +1606,49 @@ def test_no_terminal_plugin(pytester: Pytester) -> None:
     pytester.makepyfile("def test(): assert 1 == 2")
     result = pytester.runpytest("-pno:terminal", "-s")
     assert result.ret == ExitCode.TESTS_FAILED
+
+
+def test_stop_iteration_from_collect(pytester: Pytester) -> None:
+    pytester.makepyfile(test_it="raise StopIteration('hello')")
+    result = pytester.runpytest()
+    assert result.ret == ExitCode.INTERRUPTED
+    result.assert_outcomes(failed=0, passed=0, errors=1)
+    result.stdout.fnmatch_lines(
+        [
+            "=* short test summary info =*",
+            "ERROR test_it.py - StopIteration: hello",
+            "!* Interrupted: 1 error during collection !*",
+            "=* 1 error in * =*",
+        ]
+    )
+
+
+def test_stop_iteration_runtest_protocol(pytester: Pytester) -> None:
+    pytester.makepyfile(
+        test_it="""
+        import pytest
+        @pytest.fixture
+        def fail_setup():
+            raise StopIteration(1)
+        def test_fail_setup(fail_setup):
+            pass
+        def test_fail_teardown(request):
+            def stop_iteration():
+                raise StopIteration(2)
+            request.addfinalizer(stop_iteration)
+        def test_fail_call():
+            raise StopIteration(3)
+        """
+    )
+    result = pytester.runpytest()
+    assert result.ret == ExitCode.TESTS_FAILED
+    result.assert_outcomes(failed=1, passed=1, errors=2)
+    result.stdout.fnmatch_lines(
+        [
+            "=* short test summary info =*",
+            "FAILED test_it.py::test_fail_call - StopIteration: 3",
+            "ERROR test_it.py::test_fail_setup - StopIteration: 1",
+            "ERROR test_it.py::test_fail_teardown - StopIteration: 2",
+            "=* 1 failed, 1 passed, 2 errors in * =*",
+        ]
+    )