Merge pull request #547 from python/main

Sync Fork from Upstream Repo

Author: sthagen

Lib/contextlib.py

@@ -113,18 +113,20 @@ def __init__(self, func, args, kwds):
         # for the class instead.
         # See http://bugs.python.org/issue19404 for more details.
 
-
-class _GeneratorContextManager(_GeneratorContextManagerBase,
-                               AbstractContextManager,
-                               ContextDecorator):
-    """Helper for @contextmanager decorator."""
-
     def _recreate_cm(self):
-        # _GCM instances are one-shot context managers, so the
+        # _GCMB instances are one-shot context managers, so the
         # CM must be recreated each time a decorated function is
         # called
         return self.__class__(self.func, self.args, self.kwds)
 
+
+class _GeneratorContextManager(
+    _GeneratorContextManagerBase,
+    AbstractContextManager,
+    ContextDecorator,
+):
+    """Helper for @contextmanager decorator."""
+
     def __enter__(self):
         # do not keep args and kwds alive unnecessarily
         # they are only needed for recreation, which is not possible anymore
@@ -134,8 +136,8 @@ def __enter__(self):
         except StopIteration:
             raise RuntimeError("generator didn't yield") from None
 
-    def __exit__(self, type, value, traceback):
-        if type is None:
+    def __exit__(self, typ, value, traceback):
+        if typ is None:
             try:
                 next(self.gen)
             except StopIteration:
@@ -146,9 +148,9 @@ def __exit__(self, type, value, traceback):
             if value is None:
                 # Need to force instantiation so we can reliably
                 # tell if we get the same exception back
-                value = type()
+                value = typ()
             try:
-                self.gen.throw(type, value, traceback)
+                self.gen.throw(typ, value, traceback)
             except StopIteration as exc:
                 # Suppress StopIteration *unless* it's the same exception that
                 # was passed to throw().  This prevents a StopIteration
@@ -158,81 +160,93 @@ def __exit__(self, type, value, traceback):
                 # Don't re-raise the passed in exception. (issue27122)
                 if exc is value:
                     return False
-                # Likewise, avoid suppressing if a StopIteration exception
+                # Avoid suppressing if a StopIteration exception
                 # was passed to throw() and later wrapped into a RuntimeError
-                # (see PEP 479).
-                if type is StopIteration and exc.__cause__ is value:
+                # (see PEP 479 for sync generators; async generators also
+                # have this behavior). But do this only if the exception wrapped
+                # by the RuntimeError is actually Stop(Async)Iteration (see
+                # issue29692).
+                if (
+                    isinstance(value, StopIteration)
+                    and exc.__cause__ is value
+                ):
                     return False
                 raise
-            except:
+            except BaseException as exc:
                 # only re-raise if it's *not* the exception that was
                 # passed to throw(), because __exit__() must not raise
                 # an exception unless __exit__() itself failed.  But throw()
                 # has to raise the exception to signal propagation, so this
                 # fixes the impedance mismatch between the throw() protocol
                 # and the __exit__() protocol.
-                #
-                # This cannot use 'except BaseException as exc' (as in the
-                # async implementation) to maintain compatibility with
-                # Python 2, where old-style class exceptions are not caught
-                # by 'except BaseException'.
-                if sys.exc_info()[1] is value:
-                    return False
-                raise
+                if exc is not value:
+                    raise
+                return False
             raise RuntimeError("generator didn't stop after throw()")
 
-
-class _AsyncGeneratorContextManager(_GeneratorContextManagerBase,
-                                    AbstractAsyncContextManager,
-                                    AsyncContextDecorator):
-    """Helper for @asynccontextmanager."""
-
-    def _recreate_cm(self):
-        # _AGCM instances are one-shot context managers, so the
-        # ACM must be recreated each time a decorated function is
-        # called
-        return self.__class__(self.func, self.args, self.kwds)
+class _AsyncGeneratorContextManager(
+    _GeneratorContextManagerBase,
+    AbstractAsyncContextManager,
+    AsyncContextDecorator,
+):
+    """Helper for @asynccontextmanager decorator."""
 
     async def __aenter__(self):
+        # do not keep args and kwds alive unnecessarily
+        # they are only needed for recreation, which is not possible anymore
+        del self.args, self.kwds, self.func
         try:
-            return await self.gen.__anext__()
+            return await anext(self.gen)
         except StopAsyncIteration:
             raise RuntimeError("generator didn't yield") from None
 
     async def __aexit__(self, typ, value, traceback):
         if typ is None:
             try:
-                await self.gen.__anext__()
+                await anext(self.gen)
             except StopAsyncIteration:
-                return
+                return False
             else:
                 raise RuntimeError("generator didn't stop")
         else:
             if value is None:
+                # Need to force instantiation so we can reliably
+                # tell if we get the same exception back
                 value = typ()
-            # See _GeneratorContextManager.__exit__ for comments on subtleties
-            # in this implementation
             try:
                 await self.gen.athrow(typ, value, traceback)
-                raise RuntimeError("generator didn't stop after athrow()")
             except StopAsyncIteration as exc:
+                # Suppress StopIteration *unless* it's the same exception that
+                # was passed to throw().  This prevents a StopIteration
+                # raised inside the "with" statement from being suppressed.
                 return exc is not value
             except RuntimeError as exc:
+                # Don't re-raise the passed in exception. (issue27122)
                 if exc is value:
                     return False
-                # Avoid suppressing if a StopIteration exception
-                # was passed to throw() and later wrapped into a RuntimeError
+                # Avoid suppressing if a Stop(Async)Iteration exception
+                # was passed to athrow() and later wrapped into a RuntimeError
                 # (see PEP 479 for sync generators; async generators also
                 # have this behavior). But do this only if the exception wrapped
                 # by the RuntimeError is actually Stop(Async)Iteration (see
                 # issue29692).
-                if isinstance(value, (StopIteration, StopAsyncIteration)):
-                    if exc.__cause__ is value:
-                        return False
+                if (
+                    isinstance(value, (StopIteration, StopAsyncIteration))
+                    and exc.__cause__ is value
+                ):
+                    return False
                 raise
             except BaseException as exc:
+                # only re-raise if it's *not* the exception that was
+                # passed to throw(), because __exit__() must not raise
+                # an exception unless __exit__() itself failed.  But throw()
+                # has to raise the exception to signal propagation, so this
+                # fixes the impedance mismatch between the throw() protocol
+                # and the __exit__() protocol.
                 if exc is not value:
                     raise
+                return False
+            raise RuntimeError("generator didn't stop after athrow()")
 
 
 def contextmanager(func):

Lib/imghdr.py

@@ -35,9 +35,11 @@ def what(file, h=None):
 tests = []
 
 def test_jpeg(h, f):
-    """JPEG data in JFIF or Exif format"""
+    """JPEG data with JFIF or Exif markers; and raw JPEG"""
     if h[6:10] in (b'JFIF', b'Exif'):
         return 'jpeg'
+    elif h[:4] == b'\xff\xd8\xff\xdb':
+        return 'jpeg'
 
 tests.append(test_jpeg)
 

Lib/os.py

@@ -704,9 +704,11 @@ def __len__(self):
         return len(self._data)
 
     def __repr__(self):
-        return 'environ({{{}}})'.format(', '.join(
-            ('{!r}: {!r}'.format(self.decodekey(key), self.decodevalue(value))
-            for key, value in self._data.items())))
+        formatted_items = ", ".join(
+            f"{self.decodekey(key)!r}: {self.decodevalue(value)!r}"
+            for key, value in self._data.items()
+        )
+        return f"environ({{{formatted_items}}})"
 
     def copy(self):
         return dict(self)

Lib/test/imghdrdata/python-raw.jpg

@@ -126,19 +126,22 @@ def woohoo():
         self.assertEqual(state, [1, 42, 999])
 
     def test_contextmanager_except_stopiter(self):
-        stop_exc = StopIteration('spam')
         @contextmanager
         def woohoo():
             yield
-        try:
-            with self.assertWarnsRegex(DeprecationWarning,
-                                       "StopIteration"):
-                with woohoo():
-                    raise stop_exc
-        except Exception as ex:
-            self.assertIs(ex, stop_exc)
-        else:
-            self.fail('StopIteration was suppressed')
+
+        class StopIterationSubclass(StopIteration):
+            pass
+
+        for stop_exc in (StopIteration('spam'), StopIterationSubclass('spam')):
+            with self.subTest(type=type(stop_exc)):
+                try:
+                    with woohoo():
+                        raise stop_exc
+                except Exception as ex:
+                    self.assertIs(ex, stop_exc)
+                else:
+                    self.fail(f'{stop_exc} was suppressed')
 
     def test_contextmanager_except_pep479(self):
         code = """\

Lib/test/test_contextlib.py

@@ -209,7 +209,18 @@ async def test_contextmanager_except_stopiter(self):
         async def woohoo():
             yield
 
-        for stop_exc in (StopIteration('spam'), StopAsyncIteration('ham')):
+        class StopIterationSubclass(StopIteration):
+            pass
+
+        class StopAsyncIterationSubclass(StopAsyncIteration):
+            pass
+
+        for stop_exc in (
+            StopIteration('spam'),
+            StopAsyncIteration('ham'),
+            StopIterationSubclass('spam'),
+            StopAsyncIterationSubclass('spam')
+        ):
             with self.subTest(type=type(stop_exc)):
                 try:
                     async with woohoo():

Lib/test/test_contextlib_async.py

@@ -16,6 +16,7 @@
     ('python.pgm', 'pgm'),
     ('python.pbm', 'pbm'),
     ('python.jpg', 'jpeg'),
+    ('python-raw.jpg', 'jpeg'),  # raw JPEG without JFIF/EXIF markers
     ('python.ras', 'rast'),
     ('python.sgi', 'rgb'),
     ('python.tiff', 'tiff'),

Lib/test/test_imghdr.py

@@ -1029,9 +1029,11 @@ def test_items(self):
     def test___repr__(self):
         """Check that the repr() of os.environ looks like environ({...})."""
         env = os.environ
-        self.assertEqual(repr(env), 'environ({{{}}})'.format(', '.join(
-            '{!r}: {!r}'.format(key, value)
-            for key, value in env.items())))
+        formatted_items = ", ".join(
+            f"{key!r}: {value!r}"
+            for key, value in env.items()
+        )
+        self.assertEqual(repr(env), f"environ({{{formatted_items}}})")
 
     def test_get_exec_path(self):
         defpath_list = os.defpath.split(os.pathsep)

Lib/test/test_os.py

@@ -37,6 +37,7 @@
 TESTFN_SRC = TESTFN + "_SRC"
 TESTFN_DST = TESTFN + "_DST"
 MACOS = sys.platform.startswith("darwin")
+SOLARIS = sys.platform.startswith("sunos")
 AIX = sys.platform[:3] == 'aix'
 try:
     import grp
@@ -1249,7 +1250,7 @@ def test_copyfile_same_file(self):
         # Make sure file is not corrupted.
         self.assertEqual(read_file(src_file), 'foo')
 
-    @unittest.skipIf(MACOS or _winapi, 'On MACOS and Windows the errors are not confusing (though different)')
+    @unittest.skipIf(MACOS or SOLARIS or _winapi, 'On MACOS, Solaris and Windows the errors are not confusing (though different)')
     def test_copyfile_nonexistent_dir(self):
         # Issue 43219
         src_dir = self.mkdtemp()