eendebakpt · Nov 13, 2026
@@ -1106,7 +1106,7 @@ Optimizations
   Startup performance is tracked on the `Python Speed Center
   <https://speed.python.org/timeline/?exe=12&base=&ben=python_startup.legacy&env=1%2C7&revs=50&equid=off&quarts=on&extr=on>`__.
   (Contributed by Pablo Galindo Salgado, Cody Maloney, and Pieter Eendebak in
-  :gh:`159137`, :gh:`160858`, :gh:`160913`, and :gh:`87613`.)
+  :gh:`159137`, :gh:`160858`, :gh:`160913`, :gh:`87613`, and :gh:`161941`.)
 
 * Speed up iteration over asynchronous generators: values yielded to
   ``async for`` no longer create and discard a :exc:`StopIteration` exception

@@ -969,6 +969,7 @@ def _fix_up_module(cls, module):
             __path__ = spec.submodule_search_locations
             if ispkg:
                 assert __path__ == [], __path__
+                pkgdir = cls._package_dir(spec.name, pkgdir)
                 if pkgdir:
                     spec.submodule_search_locations.insert(0, pkgdir)
             else:
@@ -997,10 +998,6 @@ def _fix_up_module(cls, module):
                 (__file__, pkgdir,
                  ) = cls._resolve_filename(state.origname, spec.name, ispkg)
                 assert state.filename == __file__, (state.filename, __file__)
-                if pkgdir:
-                    assert __path__ == [pkgdir], (__path__, pkgdir)
-                else:
-                    assert __path__ == ([] if ispkg else None), __path__
             else:
                 __file__ = None
                 assert state.filename is None, state.filename
@@ -1043,6 +1040,25 @@ def _resolve_filename(cls, fullname, alias=None, ispkg=False):
             filename = f'{sys._stdlib_dir}{sep}{relfile}.py'
         return filename, pkgdir
 
+    @classmethod
+    def _package_dir(cls, fullname, pkgdir):
+        """Return the directory of the frozen package 'fullname'.
+
+        Normally this is 'pkgdir', the package's directory in the standard
+        library, so that submodules which were not frozen are found there.
+        When that directory does not exist (e.g. the standard library is
+        zipped), a standard library package is looked up on sys.path
+        instead.
+        """
+        if (_bootstrap_external is None
+                or fullname not in sys.stdlib_module_names
+                or (pkgdir and _bootstrap_external._path_isdir(pkgdir))):
+            return pkgdir
+        spec = _bootstrap_external.PathFinder.find_spec(fullname)
+        if spec is not None and spec.submodule_search_locations:
+            return spec.submodule_search_locations[0]
+        return pkgdir
+
     @classmethod
     def find_spec(cls, fullname, path=None, target=None):
         info = _call_with_frames_removed(_imp.find_frozen, fullname)
@@ -1069,6 +1085,8 @@ def find_spec(cls, fullname, path=None, target=None):
             filename=filename,
             origname=origname,
         )
+        if ispkg:
+            pkgdir = cls._package_dir(fullname, pkgdir)
         if pkgdir:
             spec.submodule_search_locations.insert(0, pkgdir)
         return spec

@@ -3,9 +3,16 @@
 machinery = util.import_importlib('importlib.machinery')
 
 import os.path
+import sys
+import tempfile
+import textwrap
 import unittest
+import zipfile
+from unittest import mock
 
-from test.support import import_helper, REPO_ROOT, STDLIB_DIR
+from test import support
+from test.support import (import_helper, os_helper, script_helper,
+                          REPO_ROOT, STDLIB_DIR)
 
 
 def resolve_stdlib_file(name, ispkg=False):
@@ -179,5 +186,64 @@ def test_not_using_frozen(self):
  ) = util.test_both(FindSpecTests, machinery=machinery)
 
 
+class PackagePathTests(unittest.TestCase):
+
+    """Test __path__ of frozen packages."""
+
+    def setUp(self):
+        self.tmpdir = tempfile.mkdtemp()
+        self.addCleanup(os_helper.rmtree, self.tmpdir)
+        self.missing_dir = os.path.join(self.tmpdir, 'does-not-exist')
+
+    def import_phello(self):
+        with (mock.patch.dict(sys.modules),
+              import_helper.frozen_modules(),
+              support.captured_stdout()):
+            sys.modules.pop('__phello__', None)
+            import __phello__
+        self.assertEqual(__phello__.__spec__.origin, 'frozen')
+        return __phello__
+
+    def test_not_in_stdlib(self):
+        # A frozen package which is not a standard library package
+        # is not looked up on sys.path.
+        os.mkdir(os.path.join(self.tmpdir, '__phello__'))
+        with open(os.path.join(self.tmpdir, '__phello__', '__init__.py'), 'wb'):
+            pass
+        for stdlib_dir, expected in [
+            (self.missing_dir, [os.path.join(self.missing_dir, '__phello__')]),
+            (None, []),
+        ]:
+            with (self.subTest(stdlib_dir=stdlib_dir),
+                  support.swap_attr(sys, 'path', [self.tmpdir, *sys.path]),
+                  support.swap_attr(sys, '_stdlib_dir', stdlib_dir)):
+                module = self.import_phello()
+                self.assertEqual(module.__path__, expected)
+
+    @support.requires_subprocess()
+    def test_zipped_stdlib(self):
+        # gh-148750: The codecs which are not frozen can be imported
+        # if the standard library is not available as a directory.
+        zipname = os.path.join(self.tmpdir, 'stdlib.zip')
+        with zipfile.ZipFile(zipname, 'w') as zf:
+            for name in ('__init__', 'cp437'):
+                zf.write(os.path.join(STDLIB_DIR, 'encodings', f'{name}.py'),
+                         f'encodings/{name}.py')
+        code = textwrap.dedent("""
+            import encodings
+            print(encodings.__spec__.origin)
+            print(encodings.__path__[0])
+            import encodings.cp437
+            print(encodings.cp437.__spec__.origin)
+            """)
+        # PYTHONHOME is a directory without a standard library.
+        proc = script_helper.assert_python_ok(
+            '-S', '-X', 'frozen_modules=on', '-c', code,
+            PYTHONHOME=self.tmpdir, PYTHONPATH=zipname)
+        pkgdir = os.path.join(zipname, 'encodings')
+        self.assertEqual(proc.out.decode().splitlines(),
+                         ['frozen', pkgdir, os.path.join(pkgdir, 'cp437.py')])
+
+
 if __name__ == '__main__':
     unittest.main()
@@ -1729,6 +1729,11 @@ FROZEN_FILES_IN = \
 		Lib/_pybuiltins.py \
 		Lib/abc.py \
 		Lib/codecs.py \
+		Lib/encodings/__init__.py \
+		Lib/encodings/aliases.py \
+		Lib/encodings/utf_8.py \
+		Lib/encodings/_win_cp_codecs.py \
+		Lib/encodings/_iconv_codecs.py \
 		Lib/io.py \
 		Lib/_collections_abc.py \
 		Lib/_sitebuiltins.py \
@@ -1756,6 +1761,11 @@ FROZEN_FILES_OUT = \
 		Python/frozen_modules/builtins.h \
 		Python/frozen_modules/abc.h \
 		Python/frozen_modules/codecs.h \
+		Python/frozen_modules/encodings.h \
+		Python/frozen_modules/encodings.aliases.h \
+		Python/frozen_modules/encodings.utf_8.h \
+		Python/frozen_modules/encodings._win_cp_codecs.h \
+		Python/frozen_modules/encodings._iconv_codecs.h \
 		Python/frozen_modules/io.h \
 		Python/frozen_modules/_collections_abc.h \
 		Python/frozen_modules/_sitebuiltins.h \
@@ -1808,6 +1818,21 @@ Python/frozen_modules/abc.h: Lib/abc.py $(FREEZE_MODULE_DEPS)
 Python/frozen_modules/codecs.h: Lib/codecs.py $(FREEZE_MODULE_DEPS)
 	$(FREEZE_MODULE) codecs $(srcdir)/Lib/codecs.py Python/frozen_modules/codecs.h
 
+Python/frozen_modules/encodings.h: Lib/encodings/__init__.py $(FREEZE_MODULE_DEPS)
+	$(FREEZE_MODULE) encodings $(srcdir)/Lib/encodings/__init__.py Python/frozen_modules/encodings.h
+
+Python/frozen_modules/encodings.aliases.h: Lib/encodings/aliases.py $(FREEZE_MODULE_DEPS)
+	$(FREEZE_MODULE) encodings.aliases $(srcdir)/Lib/encodings/aliases.py Python/frozen_modules/encodings.aliases.h
+
+Python/frozen_modules/encodings.utf_8.h: Lib/encodings/utf_8.py $(FREEZE_MODULE_DEPS)
+	$(FREEZE_MODULE) encodings.utf_8 $(srcdir)/Lib/encodings/utf_8.py Python/frozen_modules/encodings.utf_8.h
+
+Python/frozen_modules/encodings._win_cp_codecs.h: Lib/encodings/_win_cp_codecs.py $(FREEZE_MODULE_DEPS)
+	$(FREEZE_MODULE) encodings._win_cp_codecs $(srcdir)/Lib/encodings/_win_cp_codecs.py Python/frozen_modules/encodings._win_cp_codecs.h
+
+Python/frozen_modules/encodings._iconv_codecs.h: Lib/encodings/_iconv_codecs.py $(FREEZE_MODULE_DEPS)
+	$(FREEZE_MODULE) encodings._iconv_codecs $(srcdir)/Lib/encodings/_iconv_codecs.py Python/frozen_modules/encodings._iconv_codecs.h
+
 Python/frozen_modules/io.h: Lib/io.py $(FREEZE_MODULE_DEPS)
 	$(FREEZE_MODULE) io $(srcdir)/Lib/io.py Python/frozen_modules/io.h
 

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-10-14-10-12-00.gh-issue-161941.pQ7vKe.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-10-14-10-12-00.gh-issue-161941.pQ7vKe.rst
@@ -0,0 +1 @@
+The ``encodings`` package and the codecs that every interpreter imports at startup (``encodings.aliases``, ``encodings.utf_8`` and the platform codecs) are frozen again, which makes interpreter startup faster.
@@ -324,6 +324,31 @@
       <IntFile>$(IntDir)codecs.g.h</IntFile>
       <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\codecs.h</OutFile>
     </None>
+    <None Include="..\Lib\encodings\__init__.py">
+      <ModName>encodings</ModName>
+      <IntFile>$(IntDir)encodings.g.h</IntFile>
+      <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\encodings.h</OutFile>
+    </None>
+    <None Include="..\Lib\encodings\aliases.py">
+      <ModName>encodings.aliases</ModName>
+      <IntFile>$(IntDir)encodings.aliases.g.h</IntFile>
+      <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\encodings.aliases.h</OutFile>
+    </None>
+    <None Include="..\Lib\encodings\utf_8.py">
+      <ModName>encodings.utf_8</ModName>
+      <IntFile>$(IntDir)encodings.utf_8.g.h</IntFile>
+      <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\encodings.utf_8.h</OutFile>
+    </None>
+    <None Include="..\Lib\encodings\_win_cp_codecs.py">
+      <ModName>encodings._win_cp_codecs</ModName>
+      <IntFile>$(IntDir)encodings._win_cp_codecs.g.h</IntFile>
+      <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\encodings._win_cp_codecs.h</OutFile>
+    </None>
+    <None Include="..\Lib\encodings\_iconv_codecs.py">
+      <ModName>encodings._iconv_codecs</ModName>
+      <IntFile>$(IntDir)encodings._iconv_codecs.g.h</IntFile>
+      <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\encodings._iconv_codecs.h</OutFile>
+    </None>
     <None Include="..\Lib\io.py">
       <ModName>io</ModName>
       <IntFile>$(IntDir)io.g.h</IntFile>

@@ -567,6 +567,21 @@
     <None Include="..\Lib\codecs.py">
       <Filter>Python Files</Filter>
     </None>
+    <None Include="..\Lib\encodings\__init__.py">
+      <Filter>Python Files</Filter>
+    </None>
+    <None Include="..\Lib\encodings\aliases.py">
+      <Filter>Python Files</Filter>
+    </None>
+    <None Include="..\Lib\encodings\utf_8.py">
+      <Filter>Python Files</Filter>
+    </None>
+    <None Include="..\Lib\encodings\_win_cp_codecs.py">
+      <Filter>Python Files</Filter>
+    </None>
+    <None Include="..\Lib\encodings\_iconv_codecs.py">
+      <Filter>Python Files</Filter>
+    </None>
     <None Include="..\Lib\io.py">
       <Filter>Python Files</Filter>
     </None>

@@ -47,6 +47,11 @@
 #include "frozen_modules/builtins.h"
 #include "frozen_modules/abc.h"
 #include "frozen_modules/codecs.h"
+#include "frozen_modules/encodings.h"
+#include "frozen_modules/encodings.aliases.h"
+#include "frozen_modules/encodings.utf_8.h"
+#include "frozen_modules/encodings._win_cp_codecs.h"
+#include "frozen_modules/encodings._iconv_codecs.h"
 #include "frozen_modules/io.h"
 #include "frozen_modules/_collections_abc.h"
 #include "frozen_modules/_sitebuiltins.h"
@@ -79,6 +84,11 @@ static const struct _frozen stdlib_modules[] = {
     /* stdlib - startup, without site (python -S) */
     {"abc", _Py_M__abc, (int)sizeof(_Py_M__abc), false},
     {"codecs", _Py_M__codecs, (int)sizeof(_Py_M__codecs), false},
+    {"encodings", _Py_M__encodings, (int)sizeof(_Py_M__encodings), true},
+    {"encodings.aliases", _Py_M__encodings_aliases, (int)sizeof(_Py_M__encodings_aliases), false},
+    {"encodings.utf_8", _Py_M__encodings_utf_8, (int)sizeof(_Py_M__encodings_utf_8), false},
+    {"encodings._win_cp_codecs", _Py_M__encodings__win_cp_codecs, (int)sizeof(_Py_M__encodings__win_cp_codecs), false},
+    {"encodings._iconv_codecs", _Py_M__encodings__iconv_codecs, (int)sizeof(_Py_M__encodings__iconv_codecs), false},
     {"io", _Py_M__io, (int)sizeof(_Py_M__io), false},
 
     /* stdlib - startup, with site */

@@ -55,13 +55,16 @@
     ('stdlib - startup, without site (python -S)', [
         'abc',
         'codecs',
-        # gh-148750: Partially freezing encodings causes import errors of
-        # submodules when using a zipped standard library.
-        #'<encodings>',
-        #'encodings.aliases',
-        #'encodings.utf_8',
-        #'encodings._win_cp_codecs',
-        #'encodings._iconv_codecs',
+        # Only the parts of the encodings package that every interpreter
+        # imports at startup are frozen.  The other codecs are found via
+        # encodings.__path__, which FrozenImporter resolves through the
+        # path-based finders when the stdlib directory is not available
+        # (e.g. a zipped stdlib).
+        '<encodings>',
+        'encodings.aliases',
+        'encodings.utf_8',
+        'encodings._win_cp_codecs',
+        'encodings._iconv_codecs',
         'io',
         ]),
     ('stdlib - startup, with site', [
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		The ``encodings`` package and the codecs that every interpreter imports at startup (``encodings.aliases``, ``encodings.utf_8`` and the platform codecs) are frozen again, which makes interpreter startup faster.