gh-97850: Deprecate `find_loader` and `get_loader` in `pkgutil` (GH-98520)

Co-authored-by: C.A.M. Gerlach <CAM.Gerlach@Gerlach.CAM>
Co-authored-by: Brett Cannon <brett@python.org>
Co-authored-by: Oleg Iarygin <oleg@arhadthedev.net>

Doc/library/pkgutil.rst

@@ -64,6 +64,10 @@ support.
    .. versionchanged:: 3.4
       Updated to be based on :pep:`451`
 
+   .. deprecated-removed:: 3.12 3.14
+      Use :func:`importlib.util.find_spec` instead.
+
+
 .. function:: get_importer(path_item)
 
    Retrieve a :term:`finder` for the given *path_item*.
@@ -96,6 +100,9 @@ support.
    .. versionchanged:: 3.4
       Updated to be based on :pep:`451`
 
+   .. deprecated-removed:: 3.12 3.14
+      Use :func:`importlib.util.find_spec` instead.
+
 
 .. function:: iter_importers(fullname='')
 

Doc/whatsnew/3.12.rst

@@ -813,6 +813,11 @@ Pending Removal in Python 3.14
 * The *onerror* argument of :func:`shutil.rmtree` is deprecated in 3.12,
   and will be removed in 3.14.
 
+* :func:`pkgutil.find_loader` and :func:`pkgutil.get_loader`
+  now raise :exc:`DeprecationWarning`;
+  use :func:`importlib.util.find_spec` instead.
+  (Contributed by Nikita Sobolev in :gh:`97850`.)
+
 Pending Removal in Future Versions
 ----------------------------------
 

Lib/pkgutil.py

@@ -270,6 +270,10 @@ def get_loader(module_or_name):
     If the named module is not already imported, its containing package
     (if any) is imported, in order to establish the package __path__.
     """
+    warnings._deprecated("pkgutil.get_loader",
+                         f"{warnings._DEPRECATED_MSG}; "
+                         "use importlib.util.find_spec() instead",
+                         remove=(3, 14))
     if module_or_name in sys.modules:
         module_or_name = sys.modules[module_or_name]
         if module_or_name is None:
@@ -294,6 +298,10 @@ def find_loader(fullname):
     importlib.util.find_spec that converts most failures to ImportError
     and only returns the loader rather than the full spec
     """
+    warnings._deprecated("pkgutil.find_loader",
+                         f"{warnings._DEPRECATED_MSG}; "
+                         "use importlib.util.find_spec() instead",
+                         remove=(3, 14))
     if fullname.startswith('.'):
         msg = "Relative module name {!r} not supported".format(fullname)
         raise ImportError(msg)

Lib/test/test_pkgutil.py

@@ -1,6 +1,6 @@
 from pathlib import Path
 from test.support.import_helper import unload, CleanImport
-from test.support.warnings_helper import check_warnings
+from test.support.warnings_helper import check_warnings, ignore_warnings
 import unittest
 import sys
 import importlib
@@ -535,25 +535,18 @@ class ImportlibMigrationTests(unittest.TestCase):
     # PEP 302 emulation in this module is in the process of being
     # deprecated in favour of importlib proper
 
-    def test_get_loader_avoids_emulation(self):
-        with check_warnings() as w:
-            self.assertIsNotNone(pkgutil.get_loader("sys"))
-            self.assertIsNotNone(pkgutil.get_loader("os"))
-            self.assertIsNotNone(pkgutil.get_loader("test.support"))
-            self.assertEqual(len(w.warnings), 0)
-
     @unittest.skipIf(__name__ == '__main__', 'not compatible with __main__')
+    @ignore_warnings(category=DeprecationWarning)
     def test_get_loader_handles_missing_loader_attribute(self):
         global __loader__
         this_loader = __loader__
         del __loader__
         try:
-            with check_warnings() as w:
-                self.assertIsNotNone(pkgutil.get_loader(__name__))
-                self.assertEqual(len(w.warnings), 0)
+            self.assertIsNotNone(pkgutil.get_loader(__name__))
         finally:
             __loader__ = this_loader
 
+    @ignore_warnings(category=DeprecationWarning)
     def test_get_loader_handles_missing_spec_attribute(self):
         name = 'spam'
         mod = type(sys)(name)
@@ -563,6 +556,7 @@ class ImportlibMigrationTests(unittest.TestCase):
             loader = pkgutil.get_loader(name)
         self.assertIsNone(loader)
 
+    @ignore_warnings(category=DeprecationWarning)
     def test_get_loader_handles_spec_attribute_none(self):
         name = 'spam'
         mod = type(sys)(name)
@@ -572,6 +566,7 @@ class ImportlibMigrationTests(unittest.TestCase):
             loader = pkgutil.get_loader(name)
         self.assertIsNone(loader)
 
+    @ignore_warnings(category=DeprecationWarning)
     def test_get_loader_None_in_sys_modules(self):
         name = 'totally bogus'
         sys.modules[name] = None
@@ -581,18 +576,26 @@ class ImportlibMigrationTests(unittest.TestCase):
             del sys.modules[name]
         self.assertIsNone(loader)
 
+    def test_get_loader_is_deprecated(self):
+        with check_warnings(
+            (r".*\bpkgutil.get_loader\b.*", DeprecationWarning),
+        ):
+            res = pkgutil.get_loader("sys")
+        self.assertIsNotNone(res)
+
+    def test_find_loader_is_deprecated(self):
+        with check_warnings(
+            (r".*\bpkgutil.find_loader\b.*", DeprecationWarning),
+        ):
+            res = pkgutil.find_loader("sys")
+        self.assertIsNotNone(res)
+
+    @ignore_warnings(category=DeprecationWarning)
     def test_find_loader_missing_module(self):
         name = 'totally bogus'
         loader = pkgutil.find_loader(name)
         self.assertIsNone(loader)
 
-    def test_find_loader_avoids_emulation(self):
-        with check_warnings() as w:
-            self.assertIsNotNone(pkgutil.find_loader("sys"))
-            self.assertIsNotNone(pkgutil.find_loader("os"))
-            self.assertIsNotNone(pkgutil.find_loader("test.support"))
-            self.assertEqual(len(w.warnings), 0)
-
     def test_get_importer_avoids_emulation(self):
         # We use an illegal path so *none* of the path hooks should fire
         with check_warnings() as w:

Misc/NEWS.d/next/Library/2022-10-21-16-23-31.gh-issue-97850.N46coo.rst

@@ -0,0 +1,2 @@
+Deprecate :func:`pkgutil.find_loader` and :func:`pkgutil.get_loader`
+in favor of :func:`importlib.util.find_spec`.