Merge pull request #3372 from Zac-HD/using-exceptiongroups

Simple initial uses of `ExceptionGroup`

hypothesis-python/RELEASE.rst

@@ -0,0 +1,5 @@
+RELEASE_TYPE: patch
+
+We now use the :pep:`654` `ExceptionGroup <https://docs.python.org/3.11/library/exceptions.html#ExceptionGroup>`__
+type - provided by the :pypi:`exceptiongroup` backport on older Pythons -
+to ensure that if multiple errors are raised in teardown, they will all propagate.

hypothesis-python/setup.py

@@ -100,7 +100,11 @@ def local_file(name):
     description="A library for property-based testing",
     zip_safe=False,
     extras_require=extras,
-    install_requires=["attrs>=19.2.0", "sortedcontainers>=2.1.0,<3.0.0"],
+    install_requires=[
+        "attrs>=19.2.0",
+        "exceptiongroup>=1.0.0rc8 ; python_version<'3.11.0b1'",
+        "sortedcontainers>=2.1.0,<3.0.0",
+    ],
     python_requires=">=3.7",
     classifiers=[
         "Development Status :: 5 - Production/Stable",

hypothesis-python/src/hypothesis/control.py

@@ -9,11 +9,11 @@
 # obtain one at https://mozilla.org/MPL/2.0/.
 
 import math
-import traceback
 from typing import NoReturn, Union
 
 from hypothesis import Verbosity, settings
-from hypothesis.errors import CleanupFailed, InvalidArgument, UnsatisfiedAssumption
+from hypothesis.errors import InvalidArgument, UnsatisfiedAssumption
+from hypothesis.internal.compat import BaseExceptionGroup
 from hypothesis.internal.conjecture.data import ConjectureData
 from hypothesis.internal.validation import check_type
 from hypothesis.reporting import report, verbose_report
@@ -74,18 +74,16 @@ def __enter__(self):
 
     def __exit__(self, exc_type, exc_value, tb):
         self.assign_variable.__exit__(exc_type, exc_value, tb)
-        if self.close() and exc_type is None:
-            raise CleanupFailed()
-
-    def close(self):
-        any_failed = False
+        errors = []
         for task in self.tasks:
             try:
                 task()
-            except BaseException:
-                any_failed = True
-                report(traceback.format_exc())
-        return any_failed
+            except BaseException as err:
+                errors.append(err)
+        if errors:
+            if len(errors) == 1:
+                raise errors[0] from exc_value
+            raise BaseExceptionGroup("Cleanup failed", errors) from exc_value
 
 
 def cleanup(teardown):

hypothesis-python/src/hypothesis/errors.py

@@ -17,10 +17,6 @@ class _Trimmable(HypothesisException):
     """Hypothesis can trim these tracebacks even if they're raised internally."""
 
 
-class CleanupFailed(HypothesisException):
-    """At least one cleanup task failed and no other exception was raised."""
-
-
 class UnsatisfiedAssumption(HypothesisException):
     """An internal error raised by assume.
 

hypothesis-python/src/hypothesis/internal/compat.py

@@ -16,11 +16,12 @@
 
 try:
     BaseExceptionGroup = BaseExceptionGroup
-except NameError:  # pragma: no cover
-    try:
-        from exceptiongroup import BaseExceptionGroup as BaseExceptionGroup  # for mypy
-    except ImportError:
-        BaseExceptionGroup = ()  # valid in isinstance and except clauses!
+    ExceptionGroup = ExceptionGroup  # pragma: no cover
+except NameError:
+    from exceptiongroup import (
+        BaseExceptionGroup as BaseExceptionGroup,
+        ExceptionGroup as ExceptionGroup,
+    )
 
 PYPY = platform.python_implementation() == "PyPy"
 WINDOWS = platform.system() == "Windows"

hypothesis-python/src/hypothesis/strategies/_internal/types.py

@@ -28,7 +28,7 @@
 
 from hypothesis import strategies as st
 from hypothesis.errors import InvalidArgument, ResolutionFailed
-from hypothesis.internal.compat import PYPY
+from hypothesis.internal.compat import PYPY, BaseExceptionGroup, ExceptionGroup
 from hypothesis.internal.conjecture.utils import many as conjecture_utils_many
 from hypothesis.strategies._internal.datetime import zoneinfo  # type: ignore
 from hypothesis.strategies._internal.ipaddress import (
@@ -554,6 +554,16 @@ def _networks(bits):
     UnicodeTranslateError: st.builds(
         UnicodeTranslateError, st.text(), st.just(0), st.just(0), st.just("reason")
     ),
+    BaseExceptionGroup: st.builds(
+        BaseExceptionGroup,
+        st.text(),
+        st.lists(st.from_type(BaseException), min_size=1),
+    ),
+    ExceptionGroup: st.builds(
+        ExceptionGroup,
+        st.text(),
+        st.lists(st.from_type(Exception), min_size=1),
+    ),
     enumerate: st.builds(enumerate, st.just(())),
     filter: st.builds(filter, st.just(lambda _: None), st.just(())),
     map: st.builds(map, st.just(lambda _: None), st.just(())),
@@ -569,21 +579,6 @@ def _networks(bits):
     _global_type_lookup[zoneinfo.ZoneInfo] = st.timezones()
 if PYPY:
     _global_type_lookup[builtins.sequenceiterator] = st.builds(iter, st.tuples())  # type: ignore
-try:
-    BaseExceptionGroup  # type: ignore # noqa
-except NameError:
-    pass
-else:  # pragma: no cover
-    _global_type_lookup[BaseExceptionGroup] = st.builds(  # type: ignore
-        BaseExceptionGroup,  # type: ignore
-        st.text(),
-        st.lists(st.from_type(BaseException), min_size=1),
-    )
-    _global_type_lookup[ExceptionGroup] = st.builds(  # type: ignore
-        ExceptionGroup,  # type: ignore
-        st.text(),
-        st.lists(st.from_type(Exception), min_size=1),
-    )
 
 
 _global_type_lookup[type] = st.sampled_from(

hypothesis-python/tests/cover/test_control.py

@@ -20,7 +20,8 @@
     event,
     note,
 )
-from hypothesis.errors import CleanupFailed, InvalidArgument
+from hypothesis.errors import InvalidArgument
+from hypothesis.internal.compat import ExceptionGroup
 from hypothesis.internal.conjecture.data import ConjectureData as TD
 from hypothesis.stateful import RuleBasedStateMachine, rule
 from hypothesis.strategies import integers
@@ -73,44 +74,41 @@ def test_does_not_suppress_exceptions():
 
 
 def test_suppresses_exceptions_in_teardown():
-    with capture_out() as o:
-        with pytest.raises(AssertionError):
-            with bc():
+    with pytest.raises(ValueError) as err:
+        with bc():
 
-                def foo():
-                    raise ValueError()
+            def foo():
+                raise ValueError
 
-                cleanup(foo)
-                raise AssertionError
+            cleanup(foo)
+            raise AssertionError
 
-    assert "ValueError" in o.getvalue()
-    assert _current_build_context.value is None
+    assert isinstance(err.value, ValueError)
+    assert isinstance(err.value.__cause__, AssertionError)
 
 
 def test_runs_multiple_cleanup_with_teardown():
-    with capture_out() as o:
-        with pytest.raises(AssertionError):
-            with bc():
-
-                def foo():
-                    raise ValueError()
+    with pytest.raises(ExceptionGroup) as err:
+        with bc():
 
-                cleanup(foo)
+            def foo():
+                raise ValueError
 
-                def bar():
-                    raise TypeError()
+            def bar():
+                raise TypeError
 
-                cleanup(foo)
-                cleanup(bar)
-                raise AssertionError
+            cleanup(foo)
+            cleanup(bar)
+            raise AssertionError
 
-    assert "ValueError" in o.getvalue()
-    assert "TypeError" in o.getvalue()
+    assert isinstance(err.value, ExceptionGroup)
+    assert isinstance(err.value.__cause__, AssertionError)
+    assert {type(e) for e in err.value.exceptions} == {ValueError, TypeError}
     assert _current_build_context.value is None
 
 
 def test_raises_error_if_cleanup_fails_but_block_does_not():
-    with pytest.raises(CleanupFailed):
+    with pytest.raises(ValueError):
         with bc():
 
             def foo():

hypothesis-python/tests/cover/test_float_utils.py

@@ -44,6 +44,8 @@ def test_next_float_equal(func, val):
         assert func(val) == val
 
 
+# invalid order -> clamper is None:
+@example(2.0, 1.0, 3.0)
 # exponent comparisons:
 @example(1, float_info.max, 0)
 @example(1, float_info.max, 1)

hypothesis-python/tests/cover/test_stateful.py

@@ -981,6 +981,7 @@ def fail_eventually(self):
 
 def test_steps_printed_despite_pytest_fail(capsys):
     # Test for https://github.com/HypothesisWorks/hypothesis/issues/1372
+    @Settings(print_blob=False)
     class RaisesProblem(RuleBasedStateMachine):
         @rule()
         def oops(self):

hypothesis-python/tests/cover/test_verbosity.py

@@ -61,7 +61,6 @@ def test_includes_progress_in_verbose_mode():
     out = o.getvalue()
     assert out
     assert "Trying example: " in out
-    assert "Falsifying example: " in out
 
 
 def test_prints_initial_attempts_on_find():