gh-132933: Allow zipapp target to overwrite filtered source file

Author: Johannes Holmberg

Lib/test/test_zipapp.py

@@ -113,6 +113,18 @@ def test_target_overwrites_source_file(self):
         with self.assertRaises(zipapp.ZipAppError):
             zipapp.create_archive(source, target)
 
+    def test_target_overwrites_filtered_source_file(self):
+        # The target cannot be one of the files to add.
+        source = self.tmpdir
+        (source / '__main__.py').touch()
+        target = source / 'target.pyz'
+        target.touch()
+        pyz_filter = lambda p: not p.match('*.pyz')
+        zipapp.create_archive(source, target, filter=pyz_filter)
+        with zipfile.ZipFile(target, 'r') as z:
+            self.assertEqual(len(z.namelist()), 1)
+            self.assertIn('__main__.py', z.namelist())
+
     def test_create_archive_filter_exclude_dir(self):
         # Test packing a directory and using a filter to exclude a
         # subdirectory (ensures that the path supplied to include

Lib/zipapp.py

@@ -151,8 +151,12 @@ def create_archive(source, target=None, interpreter=None, main=None,
     # equal to any of the entries in files_to_add, so there's no need
     # to add a special check for that.
     if target in files_to_add:
-        raise ZipAppError(
-            f"The target archive {target} overwrites one of the source files.")
+        if filter:
+            arcname = target.relative_to(source)
+            not_filtered = filter(arcname)
+        if not filter or not_filtered:
+            raise ZipAppError(f"The target archive {target} overwrites "
+                              "one of the source files.")
 
     with _maybe_open(target, 'wb') as fd:
         _write_file_prefix(fd, interpreter)