gh-59110: zipimport: support namespace packages when no directory entry exists

Lib/test/test_zipimport.py

@@ -605,10 +605,10 @@ def testInvalidateCaches(self):
                 z.writestr(zinfo, data)
 
         zi = zipimport.zipimporter(TEMP_ZIP)
-        self.assertEqual(list(zi._get_files()), [*files, *extra_files])
+        self.assertEqual(sorted(zi._get_files()), sorted([*files, *extra_files]))
         # Check that the file information remains accurate after reloading
         zi.invalidate_caches()
-        self.assertEqual(list(zi._get_files()), [*files, *extra_files])
+        self.assertEqual(sorted(zi._get_files()), sorted([*files, *extra_files]))
         # Add a new file to the ZIP archive
         newfile = {"spam2" + pyc_ext: (NOW, test_pyc)}
         files.update(newfile)
@@ -620,7 +620,7 @@ def testInvalidateCaches(self):
                 z.writestr(zinfo, data)
         # Check that we can detect the new file after invalidating the cache
         zi.invalidate_caches()
-        self.assertEqual(list(zi._get_files()), [*files, *extra_files])
+        self.assertEqual(sorted(zi._get_files()), sorted([*files, *extra_files]))
         spec = zi.find_spec('spam2')
         self.assertIsNotNone(spec)
         self.assertIsInstance(spec.loader, zipimport.zipimporter)
@@ -648,10 +648,10 @@ def testInvalidateCachesWithMultipleZipimports(self):
                 z.writestr(zinfo, data)
 
         zi = zipimport.zipimporter(TEMP_ZIP)
-        self.assertEqual(list(zi._get_files()), [*files, *extra_files])
+        self.assertEqual(sorted(zi._get_files()), sorted([*files, *extra_files]))
         # Zipimporter for the same path.
         zi2 = zipimport.zipimporter(TEMP_ZIP)
-        self.assertEqual(list(zi2._get_files()), [*files, *extra_files])
+        self.assertEqual(sorted(zi2._get_files()), sorted([*files, *extra_files]))
         # Add a new file to the ZIP archive to make the cache wrong.
         newfile = {"spam2" + pyc_ext: (NOW, test_pyc)}
         files.update(newfile)
@@ -664,7 +664,7 @@ def testInvalidateCachesWithMultipleZipimports(self):
         # Invalidate the cache of the first zipimporter.
         zi.invalidate_caches()
         # Check that the second zipimporter detects the new file and isn't using a stale cache.
-        self.assertEqual(list(zi2._get_files()), [*files, *extra_files])
+        self.assertEqual(sorted(zi2._get_files()), sorted([*files, *extra_files]))
         spec = zi2.find_spec('spam2')
         self.assertIsNotNone(spec)
         self.assertIsInstance(spec.loader, zipimport.zipimporter)

Lib/zipimport.py

@@ -556,12 +556,20 @@ def _read_directory(archive):
         finally:
             fp.seek(start_offset)
     _bootstrap._verbose_message('zipimport: found {} names in {!r}', count, archive)
+
+    # Add implicit directories.
     for name in list(files):
-        while (i := name.rstrip(path_sep).rfind(path_sep)) >= 0:
+        while True:
+            i = name.rstrip(path_sep).rfind(path_sep)
+            if i < 0:
+                break
             name = name[:i + 1]
             if name in files:
                 break
             files[name] = None
+            count += 1
+    _bootstrap._verbose_message('zipimport: added {} implicit directories in {!r}',
+                                count, archive)
     return files
 
 # During bootstrap, we may need to load the encodings

Misc/NEWS.d/next/Library/2024-07-04-17-36-03.gh-issue-59110.IlI9Fz.rst

@@ -0,0 +1,2 @@
+:mod:`zipimport` supports now namespace packages when no directory entry
+exists.