Inline the find_distributions functionality on PathFinder.

Lib/importlib/_bootstrap_external.py

@@ -1359,6 +1359,57 @@ class PathFinder:
             return None
         return spec.loader
 
+    search_template = r'{pattern}(-.*)?\.(dist|egg)-info'
+
+    @classmethod
+    def find_distributions(cls, name=None, path=None):
+        """Return an iterable of all Distribution instances capable of
+        loading the metadata for packages matching the name
+        (or all names if not supplied) along the paths in the list
+        of directories ``path`` (defaults to sys.path).
+        """
+        import re
+        from importlib.metadata._hooks import PathDistribution
+        if path is None:
+            path = sys.path
+        pattern = '.*' if name is None else re.escape(name)
+        found = cls._search_paths(pattern, path)
+        return map(PathDistribution, found)
+
+    @classmethod
+    def _search_paths(cls, pattern, paths):
+        """
+        Find metadata directories in paths heuristically.
+        """
+        import itertools
+        return itertools.chain.from_iterable(
+            cls._search_path(path, pattern)
+            for path in map(cls._switch_path, paths)
+            )
+
+    @staticmethod
+    def _switch_path(path):
+        from contextlib import suppress
+        import zipfile
+        from pathlib import Path
+        with suppress(Exception):
+            return zipfile.Path(path)
+        return Path(path)
+
+    @classmethod
+    def _predicate(cls, pattern, root, item):
+        import re
+        return re.match(pattern, str(item.name), flags=re.IGNORECASE)
+
+    @classmethod
+    def _search_path(cls, root, pattern):
+        if not root.is_dir():
+            return ()
+        normalized = pattern.replace('-', '_')
+        matcher = cls.search_template.format(pattern=normalized)
+        return (item for item in root.iterdir()
+                if cls._predicate(matcher, root, item))
+
 
 class FileFinder:
 

Lib/importlib/metadata/_hooks.py

@@ -1,12 +1,8 @@
-import re
 import sys
-import zipfile
-import itertools
 
 from .api import Distribution
 from .abc import DistributionFinder
 from contextlib import suppress
-from pathlib import Path
 
 
 def install(cls):
@@ -25,57 +21,6 @@ class NullFinder(DistributionFinder):
         return None
 
 
-@install
-class MetadataPathFinder(NullFinder):
-    """A degenerate finder for distribution packages on the file system.
-
-    This finder supplies only a find_distributions() method for versions
-    of Python that do not have a PathFinder find_distributions().
-    """
-    search_template = r'{pattern}(-.*)?\.(dist|egg)-info'
-
-    def find_distributions(self, name=None, path=None):
-        """Return an iterable of all Distribution instances capable of
-        loading the metadata for packages matching the name
-        (or all names if not supplied) along the paths in the list
-        of directories ``path`` (defaults to sys.path).
-        """
-        if path is None:
-            path = sys.path
-        pattern = '.*' if name is None else re.escape(name)
-        found = self._search_paths(pattern, path)
-        return map(PathDistribution, found)
-
-    @classmethod
-    def _search_paths(cls, pattern, paths):
-        """
-        Find metadata directories in paths heuristically.
-        """
-        return itertools.chain.from_iterable(
-            cls._search_path(path, pattern)
-            for path in map(cls._switch_path, paths)
-            )
-
-    @staticmethod
-    def _switch_path(path):
-        with suppress(Exception):
-            return zipfile.Path(path)
-        return Path(path)
-
-    @classmethod
-    def _predicate(cls, pattern, root, item):
-        return re.match(pattern, str(item.name), flags=re.IGNORECASE)
-
-    @classmethod
-    def _search_path(cls, root, pattern):
-        if not root.is_dir():
-            return ()
-        normalized = pattern.replace('-', '_')
-        matcher = cls.search_template.format(pattern=normalized)
-        return (item for item in root.iterdir()
-                if cls._predicate(matcher, root, item))
-
-
 class PathDistribution(Distribution):
     def __init__(self, path):
         """Construct a distribution from a path to the metadata directory."""

Lib/test/test_importlib/test_main.py

@@ -7,7 +7,7 @@ import importlib
 
 from . import fixtures
 from importlib.metadata import (
-    Distribution, PackageNotFoundError, _hooks, api, distributions,
+    Distribution, PackageNotFoundError, api, distributions,
     entry_points, metadata, version)
 
 
@@ -25,7 +25,6 @@ class BasicTests(fixtures.DistInfoPkg, unittest.TestCase):
 
     def test_new_style_classes(self):
         self.assertIsInstance(Distribution, type)
-        self.assertIsInstance(_hooks.MetadataPathFinder, type)
 
 
 class ImportTests(fixtures.DistInfoPkg, unittest.TestCase):