bpo-42136: Deprecate module_repr() as found in importlib (GH-25022)

Author: brettcannon

Doc/reference/import.rst

@@ -675,6 +675,13 @@ Here are the exact rules used:
    :meth:`~importlib.abc.Loader.module_repr` method, if defined, before
    trying either approach described above.  However, the method is deprecated.
 
+.. versionchanged:: 3.10
+
+   Calling :meth:`~importlib.abc.Loader.module_repr` now occurs after trying to
+   use a module's ``__spec__`` attribute but before falling back on
+   ``__file__``. Use of :meth:`~importlib.abc.Loader.module_repr` is slated to
+   stop in Python 3.12.
+
 .. _pyc-invalidation:
 
 Cached bytecode invalidation

Doc/whatsnew/3.10.rst

@@ -1010,6 +1010,12 @@ Deprecated
   for Python 3.12.
   (Contributed by Brett Cannon in :issue:`42137`.)
 
+* :meth:`importlib.abc.Loader.module_repr`,
+  :meth:`importlib.machinery.FrozenLoader.module_repr`, and
+  :meth:`importlib.machinery.BuiltinLoader.module_repr` are deprecated and
+  slated for removal in Python 3.12.
+  (Contributed by Brett Cannon in :issue:`42136`.)
+
 * ``sqlite3.OptimizedUnicode`` has been undocumented and obsolete since Python
   3.3, when it was made an alias to :class:`str`.  It is now deprecated,
   scheduled for removal in Python 3.12.

Lib/importlib/_abc.py

@@ -1,6 +1,7 @@
 """Subset of importlib.abc used to reduce importlib.util imports."""
 from . import _bootstrap
 import abc
+import warnings
 
 
 class Loader(metaclass=abc.ABCMeta):
@@ -47,5 +48,7 @@ def module_repr(self, module):
         This method is deprecated.
 
         """
+        warnings.warn("importlib.abc.Loader.module_repr() is deprecated and "
+                      "slated for removal in Python 3.12", DeprecationWarning)
         # The exception will cause ModuleType.__repr__ to ignore this method.
         raise NotImplementedError

Lib/importlib/_bootstrap.py

@@ -302,8 +302,6 @@ def _module_repr(module):
         except Exception:
             pass
     # Fall through to a catch-all which always succeeds.
-    # We could use module.__class__.__name__ instead of 'module' in the
-    # various repr permutations.
     try:
         name = module.__name__
     except AttributeError:
@@ -741,6 +739,8 @@ def module_repr(module):
         The method is deprecated.  The import machinery does the job itself.
 
         """
+        _warnings.warn("BuiltinImporter.module_repr() is deprecated and "
+                       "slated for removal in Python 3.12", DeprecationWarning)
         return f'<module {module.__name__!r} ({BuiltinImporter._ORIGIN})>'
 
     @classmethod
@@ -816,6 +816,8 @@ def module_repr(m):
         The method is deprecated.  The import machinery does the job itself.
 
         """
+        _warnings.warn("FrozenImporter.module_repr() is deprecated and "
+                       "slated for removal in Python 3.12", DeprecationWarning)
         return '<module {!r} ({})>'.format(m.__name__, FrozenImporter._ORIGIN)
 
     @classmethod

Lib/importlib/_bootstrap_external.py

@@ -1230,6 +1230,8 @@ def module_repr(module):
         The method is deprecated.  The import machinery does the job itself.
 
         """
+        _warnings.warn("_NamespaceLoader.module_repr() is deprecated and "
+                       "slated for removal in Python 3.12", DeprecationWarning)
         return '<module {!r} (namespace)>'.format(module.__name__)
 
     def is_package(self, fullname):

Lib/test/test_importlib/test_abc.py

@@ -220,8 +220,10 @@ def test_load_module(self):
 
     def test_module_repr(self):
         mod = types.ModuleType('blah')
-        with self.assertRaises(NotImplementedError):
-            self.ins.module_repr(mod)
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore")
+            with self.assertRaises(NotImplementedError):
+                self.ins.module_repr(mod)
         original_repr = repr(mod)
         mod.__loader__ = self.ins
         # Should still return a proper repr.

Lib/test/test_importlib/test_namespace_pkgs.py

@@ -3,6 +3,7 @@
 import os
 import sys
 import unittest
+import warnings
 
 from test.test_importlib import util
 
@@ -82,8 +83,10 @@ def test_cant_import_other(self):
 
     def test_module_repr(self):
         import foo.one
-        self.assertEqual(foo.__spec__.loader.module_repr(foo),
-                         "<module 'foo' (namespace)>")
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore")
+            self.assertEqual(foo.__spec__.loader.module_repr(foo),
+                            "<module 'foo' (namespace)>")
 
 
 class DynamicPathNamespacePackage(NamespacePackageTest):

Lib/test/test_importlib/test_windows.py

@@ -7,7 +7,6 @@
 import unittest
 from test import support
 from test.support import import_helper
-from distutils.util import get_platform
 from contextlib import contextmanager
 from .util import temp_module
 
@@ -18,6 +17,25 @@
     EnumKey, CloseKey, DeleteKey, OpenKey
 )
 
+def get_platform():
+    # Port of distutils.util.get_platform().
+    TARGET_TO_PLAT = {
+            'x86' : 'win32',
+            'x64' : 'win-amd64',
+            'arm' : 'win-arm32',
+        }
+    if ('VSCMD_ARG_TGT_ARCH' in os.environ and
+        os.environ['VSCMD_ARG_TGT_ARCH'] in TARGET_TO_PLAT):
+        return TARGET_TO_PLAT[os.environ['VSCMD_ARG_TGT_ARCH']]
+    elif 'amd64' in sys.version.lower():
+        return 'win-amd64'
+    elif '(arm)' in sys.version.lower():
+        return 'win-arm32'
+    elif '(arm64)' in sys.version.lower():
+        return 'win-arm64'
+    else:
+        return sys.platform
+
 def delete_registry_tree(root, subkey):
     try:
         hkey = OpenKey(root, subkey, access=KEY_ALL_ACCESS)
@@ -101,7 +119,7 @@ def test_tagged_suffix(self):
 
         self.assertIn(expected_tag, suffixes)
 
-        # Ensure the tags are in the correct order
+        # Ensure the tags are in the correct order.
         tagged_i = suffixes.index(expected_tag)
         self.assertLess(tagged_i, untagged_i)
 

Misc/NEWS.d/next/Library/2021-03-25-08-44-26.bpo-42136.rRY9e1.rst

@@ -0,0 +1,2 @@
+Deprecate all module_repr() methods found in importlib as their use is being
+phased out by Python 3.12.