Update contextlib from CPython 3.12

Lib/contextlib.py

@@ -145,14 +145,17 @@ class _GeneratorContextManager(
             except StopIteration:
                 return False
             else:
-                raise RuntimeError("generator didn't stop")
+                try:
+                    raise RuntimeError("generator didn't stop")
+                finally:
+                    self.gen.close()
         else:
             if value is None:
                 # Need to force instantiation so we can reliably
                 # tell if we get the same exception back
                 value = typ()
             try:
-                self.gen.throw(typ, value, traceback)
+                self.gen.throw(value)
             except StopIteration as exc:
                 # Suppress StopIteration *unless* it's the same exception that
                 # was passed to throw().  This prevents a StopIteration
@@ -187,7 +190,10 @@ class _GeneratorContextManager(
                     raise
                 exc.__traceback__ = traceback
                 return False
-            raise RuntimeError("generator didn't stop after throw()")
+            try:
+                raise RuntimeError("generator didn't stop after throw()")
+            finally:
+                self.gen.close()
 
 class _AsyncGeneratorContextManager(
     _GeneratorContextManagerBase,
@@ -212,14 +218,17 @@ class _AsyncGeneratorContextManager(
             except StopAsyncIteration:
                 return False
             else:
-                raise RuntimeError("generator didn't stop")
+                try:
+                    raise RuntimeError("generator didn't stop")
+                finally:
+                    await self.gen.aclose()
         else:
             if value is None:
                 # Need to force instantiation so we can reliably
                 # tell if we get the same exception back
                 value = typ()
             try:
-                await self.gen.athrow(typ, value, traceback)
+                await self.gen.athrow(value)
             except StopAsyncIteration as exc:
                 # Suppress StopIteration *unless* it's the same exception that
                 # was passed to throw().  This prevents a StopIteration
@@ -254,7 +263,10 @@ class _AsyncGeneratorContextManager(
                     raise
                 exc.__traceback__ = traceback
                 return False
-            raise RuntimeError("generator didn't stop after athrow()")
+            try:
+                raise RuntimeError("generator didn't stop after athrow()")
+            finally:
+                await self.gen.aclose()
 
 
 def contextmanager(func):
@@ -441,7 +453,16 @@ class suppress(AbstractContextManager):
         # exactly reproduce the limitations of the CPython interpreter.
         #
         # See http://bugs.python.org/issue12029 for more details
-        return exctype is not None and issubclass(exctype, self._exceptions)
+        if exctype is None:
+            return
+        if issubclass(exctype, self._exceptions):
+            return True
+        if issubclass(exctype, BaseExceptionGroup):
+            match, rest = excinst.split(self._exceptions)
+            if rest is None:
+                return True
+            raise rest
+        return False
 
 
 class _BaseExitStack:

Lib/test/test_contextlib.py

@@ -10,6 +10,7 @@ import unittest
 from contextlib import *  # Tests __all__
 from test import support
 from test.support import os_helper
+from test.support.testcase import ExceptionIsLikeMixin
 import weakref
 
 
@@ -158,9 +159,45 @@ class ContextManagerTestCase(unittest.TestCase):
                 yield
         ctx = whoo()
         ctx.__enter__()
-        self.assertRaises(
-            RuntimeError, ctx.__exit__, TypeError, TypeError("foo"), None
-        )
+        with self.assertRaises(RuntimeError):
+            ctx.__exit__(TypeError, TypeError("foo"), None)
+        if support.check_impl_detail(cpython=True):
+            # The "gen" attribute is an implementation detail.
+            self.assertFalse(ctx.gen.gi_suspended)
+
+    def test_contextmanager_trap_no_yield(self):
+        @contextmanager
+        def whoo():
+            if False:
+                yield
+        ctx = whoo()
+        with self.assertRaises(RuntimeError):
+            ctx.__enter__()
+
+    def test_contextmanager_trap_second_yield(self):
+        @contextmanager
+        def whoo():
+            yield
+            yield
+        ctx = whoo()
+        ctx.__enter__()
+        with self.assertRaises(RuntimeError):
+            ctx.__exit__(None, None, None)
+        if support.check_impl_detail(cpython=True):
+            # The "gen" attribute is an implementation detail.
+            self.assertFalse(ctx.gen.gi_suspended)
+
+    def test_contextmanager_non_normalised(self):
+        @contextmanager
+        def whoo():
+            try:
+                yield
+            except RuntimeError:
+                raise SyntaxError
+        ctx = whoo()
+        ctx.__enter__()
+        with self.assertRaises(SyntaxError):
+            ctx.__exit__(RuntimeError, None, None)
 
     def test_contextmanager_except(self):
         state = []
@@ -241,6 +278,23 @@ def woohoo():
             self.assertEqual(ex.args[0], 'issue29692:Unchained')
             self.assertIsNone(ex.__cause__)
 
+    def test_contextmanager_wrap_runtimeerror(self):
+        @contextmanager
+        def woohoo():
+            try:
+                yield
+            except Exception as exc:
+                raise RuntimeError(f'caught {exc}') from exc
+        with self.assertRaises(RuntimeError):
+            with woohoo():
+                1 / 0
+        # If the context manager wrapped StopIteration in a RuntimeError,
+        # we also unwrap it, because we can't tell whether the wrapping was
+        # done by the generator machinery or by the generator itself.
+        with self.assertRaises(StopIteration):
+            with woohoo():
+                raise StopIteration
+
     def _create_contextmanager_attribs(self):
         def attribs(**kw):
             def decorate(func):
@@ -252,6 +306,7 @@ def woohoo():
         @attribs(foo='bar')
         def baz(spam):
             """Whee!"""
+            yield
         return baz
 
     def test_contextmanager_attribs(self):
@@ -308,8 +363,11 @@ def woohoo():
 
     def test_recursive(self):
         depth = 0
+        ncols = 0
         @contextmanager
         def woohoo():
+            nonlocal ncols
+            ncols += 1
             nonlocal depth
             before = depth
             depth += 1
@@ -323,6 +381,7 @@ def woohoo():
                 recursive()
 
         recursive()
+        self.assertEqual(ncols, 10)
         self.assertEqual(depth, 0)
 
 
@@ -374,12 +433,10 @@ class FileContextTestCase(unittest.TestCase):
     def testWithOpen(self):
         tfn = tempfile.mktemp()
         try:
-            f = None
             with open(tfn, "w", encoding="utf-8") as f:
                 self.assertFalse(f.closed)
                 f.write("Booh\n")
             self.assertTrue(f.closed)
-            f = None
             with self.assertRaises(ZeroDivisionError):
                 with open(tfn, "r", encoding="utf-8") as f:
                     self.assertFalse(f.closed)
@@ -1160,7 +1217,7 @@ class TestRedirectStderr(TestRedirectStream, unittest.TestCase):
     orig_stream = "stderr"
 
 
-class TestSuppress(unittest.TestCase):
+class TestSuppress(ExceptionIsLikeMixin, unittest.TestCase):
 
     @support.requires_docstrings
     def test_instance_docs(self):
@@ -1214,6 +1271,51 @@ class TestSuppress(unittest.TestCase):
             1/0
         self.assertTrue(outer_continued)
 
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_exception_groups(self):
+        eg_ve = lambda: ExceptionGroup(
+            "EG with ValueErrors only",
+            [ValueError("ve1"), ValueError("ve2"), ValueError("ve3")],
+        )
+        eg_all = lambda: ExceptionGroup(
+            "EG with many types of exceptions",
+            [ValueError("ve1"), KeyError("ke1"), ValueError("ve2"), KeyError("ke2")],
+        )
+        with suppress(ValueError):
+            raise eg_ve()
+        with suppress(ValueError, KeyError):
+            raise eg_all()
+        with self.assertRaises(ExceptionGroup) as eg1:
+            with suppress(ValueError):
+                raise eg_all()
+        self.assertExceptionIsLike(
+            eg1.exception,
+            ExceptionGroup(
+                "EG with many types of exceptions",
+                [KeyError("ke1"), KeyError("ke2")],
+            ),
+        )
+
+        # Check handling of BaseExceptionGroup, using GeneratorExit so that
+        # we don't accidentally discard a ctrl-c with KeyboardInterrupt.
+        with suppress(GeneratorExit):
+            raise BaseExceptionGroup("message", [GeneratorExit()])
+        # If we raise a BaseException group, we can still suppress parts
+        with self.assertRaises(BaseExceptionGroup) as eg1:
+            with suppress(KeyError):
+                raise BaseExceptionGroup("message", [GeneratorExit("g"), KeyError("k")])
+        self.assertExceptionIsLike(
+            eg1.exception, BaseExceptionGroup("message", [GeneratorExit("g")]),
+        )
+        # If we suppress all the leaf BaseExceptions, we get a non-base ExceptionGroup
+        with self.assertRaises(ExceptionGroup) as eg1:
+            with suppress(GeneratorExit):
+                raise BaseExceptionGroup("message", [GeneratorExit("g"), KeyError("k")])
+        self.assertExceptionIsLike(
+            eg1.exception, ExceptionGroup("message", [KeyError("k")]),
+        )
+
 
 class TestChdir(unittest.TestCase):
     def make_relative_path(self, *parts):