Revert "pythongh-132947: Apply changes from importlib_metadata 8.7 (python#137885)" (python#137924)

This reverts commit 5292fc0.

Author: jaraco

Lib/importlib/metadata/__init__.py

@@ -1,58 +1,11 @@
-import email.message
-import email.policy
 import re
 import textwrap
+import email.message
 
 from ._text import FoldedCase
 
 
-class RawPolicy(email.policy.EmailPolicy):
-    def fold(self, name, value):
-        folded = self.linesep.join(
-            textwrap.indent(value, prefix=' ' * 8, predicate=lambda line: True)
-            .lstrip()
-            .splitlines()
-        )
-        return f'{name}: {folded}{self.linesep}'
-
-
 class Message(email.message.Message):
-    r"""
-    Specialized Message subclass to handle metadata naturally.
-
-    Reads values that may have newlines in them and converts the
-    payload to the Description.
-
-    >>> msg_text = textwrap.dedent('''
-    ...     Name: Foo
-    ...     Version: 3.0
-    ...     License: blah
-    ...             de-blah
-    ...     <BLANKLINE>
-    ...     First line of description.
-    ...     Second line of description.
-    ...     <BLANKLINE>
-    ...     Fourth line!
-    ...     ''').lstrip().replace('<BLANKLINE>', '')
-    >>> msg = Message(email.message_from_string(msg_text))
-    >>> msg['Description']
-    'First line of description.\nSecond line of description.\n\nFourth line!\n'
-
-    Message should render even if values contain newlines.
-
-    >>> print(msg)
-    Name: Foo
-    Version: 3.0
-    License: blah
-            de-blah
-    Description: First line of description.
-            Second line of description.
-    <BLANKLINE>
-            Fourth line!
-    <BLANKLINE>
-    <BLANKLINE>
-    """
-
     multiple_use_keys = set(
         map(
             FoldedCase,
@@ -104,20 +57,15 @@ def __getitem__(self, item):
     def _repair_headers(self):
         def redent(value):
             "Correct for RFC822 indentation"
-            indent = ' ' * 8
-            if not value or '\n' + indent not in value:
+            if not value or '\n' not in value:
                 return value
-            return textwrap.dedent(indent + value)
+            return textwrap.dedent(' ' * 8 + value)
 
         headers = [(key, redent(value)) for key, value in vars(self)['_headers']]
         if self._payload:
             headers.append(('Description', self.get_payload()))
-            self.set_payload('')
         return headers
 
-    def as_string(self):
-        return super().as_string(policy=RawPolicy())
-
     @property
     def json(self):
         """

Lib/importlib/metadata/_adapters.py

@@ -1,5 +1,4 @@
 import collections
-import typing
 
 
 # from jaraco.collections 3.3
@@ -25,10 +24,7 @@ def freeze(self):
         self._frozen = lambda key: self.default_factory()
 
 
-class Pair(typing.NamedTuple):
-    name: str
-    value: str
-
+class Pair(collections.namedtuple('Pair', 'name value')):
     @classmethod
     def parse(cls, text):
         return cls(*map(str.strip, text.split("=", 1)))

Lib/importlib/metadata/_collections.py

@@ -1,5 +1,5 @@
-import functools
 import types
+import functools
 
 
 # from jaraco.functools 3.3

Lib/importlib/metadata/_functools.py

@@ -1,13 +1,9 @@
 from __future__ import annotations
 
 import os
-from collections.abc import Iterator
-from typing import (
-    Any,
-    Protocol,
-    TypeVar,
-    overload,
-)
+from typing import Protocol
+from typing import Any, Dict, Iterator, List, Optional, TypeVar, Union, overload
+
 
 _T = TypeVar("_T")
 
@@ -24,25 +20,25 @@ def __iter__(self) -> Iterator[str]: ...  # pragma: no cover
     @overload
     def get(
         self, name: str, failobj: None = None
-    ) -> str | None: ...  # pragma: no cover
+    ) -> Optional[str]: ...  # pragma: no cover
 
     @overload
-    def get(self, name: str, failobj: _T) -> str | _T: ...  # pragma: no cover
+    def get(self, name: str, failobj: _T) -> Union[str, _T]: ...  # pragma: no cover
 
     # overload per python/importlib_metadata#435
     @overload
     def get_all(
         self, name: str, failobj: None = None
-    ) -> list[Any] | None: ...  # pragma: no cover
+    ) -> Optional[List[Any]]: ...  # pragma: no cover
 
     @overload
-    def get_all(self, name: str, failobj: _T) -> list[Any] | _T:
+    def get_all(self, name: str, failobj: _T) -> Union[List[Any], _T]:
         """
         Return all values associated with a possibly multi-valued key.
         """
 
     @property
-    def json(self) -> dict[str, str | list[str]]:
+    def json(self) -> Dict[str, Union[str, List[str]]]:
         """
         A JSON-compatible form of the metadata.
         """
@@ -54,11 +50,11 @@ class SimplePath(Protocol):
     """
 
     def joinpath(
-        self, other: str | os.PathLike[str]
+        self, other: Union[str, os.PathLike[str]]
     ) -> SimplePath: ...  # pragma: no cover
 
     def __truediv__(
-        self, other: str | os.PathLike[str]
+        self, other: Union[str, os.PathLike[str]]
     ) -> SimplePath: ...  # pragma: no cover
 
     @property

Lib/importlib/metadata/_meta.py

@@ -1,14 +1,9 @@
-# from jaraco.path 3.7.2
-
-from __future__ import annotations
+# from jaraco.path 3.7
 
 import functools
 import pathlib
-from collections.abc import Mapping
-from typing import TYPE_CHECKING, Protocol, Union, runtime_checkable
-
-if TYPE_CHECKING:
-    from typing_extensions import Self
+from typing import Dict, Protocol, Union
+from typing import runtime_checkable
 
 
 class Symlink(str):
@@ -17,25 +12,29 @@ class Symlink(str):
     """
 
 
-FilesSpec = Mapping[str, Union[str, bytes, Symlink, 'FilesSpec']]
+FilesSpec = Dict[str, Union[str, bytes, Symlink, 'FilesSpec']]  # type: ignore
 
 
 @runtime_checkable
 class TreeMaker(Protocol):
-    def __truediv__(self, other, /) -> Self: ...
-    def mkdir(self, *, exist_ok) -> object: ...
-    def write_text(self, content, /, *, encoding) -> object: ...
-    def write_bytes(self, content, /) -> object: ...
-    def symlink_to(self, target, /) -> object: ...
+    def __truediv__(self, *args, **kwargs): ...  # pragma: no cover
+
+    def mkdir(self, **kwargs): ...  # pragma: no cover
+
+    def write_text(self, content, **kwargs): ...  # pragma: no cover
+
+    def write_bytes(self, content): ...  # pragma: no cover
+
+    def symlink_to(self, target): ...  # pragma: no cover
 
 
-def _ensure_tree_maker(obj: str | TreeMaker) -> TreeMaker:
-    return obj if isinstance(obj, TreeMaker) else pathlib.Path(obj)
+def _ensure_tree_maker(obj: Union[str, TreeMaker]) -> TreeMaker:
+    return obj if isinstance(obj, TreeMaker) else pathlib.Path(obj)  # type: ignore
 
 
 def build(
     spec: FilesSpec,
-    prefix: str | TreeMaker = pathlib.Path(),
+    prefix: Union[str, TreeMaker] = pathlib.Path(),  # type: ignore
 ):
     """
     Build a set of files/directories, as described by the spec.
@@ -67,24 +66,23 @@ def build(
 
 
 @functools.singledispatch
-def create(content: str | bytes | FilesSpec, path: TreeMaker) -> None:
+def create(content: Union[str, bytes, FilesSpec], path):
     path.mkdir(exist_ok=True)
-    # Mypy only looks at the signature of the main singledispatch method. So it must contain the complete Union
-    build(content, prefix=path)  # type: ignore[arg-type] # python/mypy#11727
+    build(content, prefix=path)  # type: ignore
 
 
 @create.register
-def _(content: bytes, path: TreeMaker) -> None:
+def _(content: bytes, path):
     path.write_bytes(content)
 
 
 @create.register
-def _(content: str, path: TreeMaker) -> None:
+def _(content: str, path):
     path.write_text(content, encoding='utf-8')
 
 
 @create.register
-def _(content: Symlink, path: TreeMaker) -> None:
+def _(content: Symlink, path):
     path.symlink_to(content)
 
 

Lib/importlib/metadata/_typing.py

@@ -1,11 +1,11 @@
-import contextlib
+import sys
 import copy
-import functools
 import json
-import pathlib
 import shutil
-import sys
+import pathlib
 import textwrap
+import functools
+import contextlib
 
 from test.support import import_helper
 from test.support import os_helper
@@ -14,10 +14,14 @@
 from . import _path
 from ._path import FilesSpec
 
-if sys.version_info >= (3, 9):
-    from importlib import resources
-else:
-    import importlib_resources as resources
+
+try:
+    from importlib import resources  # type: ignore
+
+    getattr(resources, 'files')
+    getattr(resources, 'as_file')
+except (ImportError, AttributeError):
+    import importlib_resources as resources  # type: ignore
 
 
 @contextlib.contextmanager

Lib/test/test_importlib/metadata/_path.py

@@ -1,8 +1,9 @@
-import importlib
 import re
 import textwrap
 import unittest
+import importlib
 
+from . import fixtures
 from importlib.metadata import (
     Distribution,
     PackageNotFoundError,
@@ -14,8 +15,6 @@
     version,
 )
 
-from . import fixtures
-
 
 class APITests(
     fixtures.EggInfoPkg,

Lib/test/test_importlib/metadata/fixtures.py

@@ -1,14 +1,17 @@
-import importlib
-import pickle
 import re
+import pickle
 import unittest
+import importlib
+import importlib.metadata
 from test.support import os_helper
 
 try:
     import pyfakefs.fake_filesystem_unittest as ffs
 except ImportError:
     from .stubs import fake_filesystem_unittest as ffs
 
+from . import fixtures
+from ._path import Symlink
 from importlib.metadata import (
     Distribution,
     EntryPoint,
@@ -21,9 +24,6 @@
     version,
 )
 
-from . import fixtures
-from ._path import Symlink
-
 
 class BasicTests(fixtures.DistInfoPkg, unittest.TestCase):
     version_pattern = r'\d+\.\d+(\.\d)?'
@@ -157,16 +157,6 @@ def test_valid_dists_preferred(self):
         dist = Distribution.from_name('foo')
         assert dist.version == "1.0"
 
-    def test_missing_metadata(self):
-        """
-        Dists with a missing metadata file should return None.
-
-        Ref python/importlib_metadata#493.
-        """
-        fixtures.build_files(self.make_pkg('foo-4.3', files={}), self.site_dir)
-        assert Distribution.from_name('foo').metadata is None
-        assert metadata('foo') is None
-
 
 class NonASCIITests(fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase):
     @staticmethod