Remove data_offset updating

- The `data_offset` attribute is retracted in 3.14rc:
  ref: python/cpython#136950

Author: danny0838

src/zipremove/__init__.py

@@ -177,8 +177,7 @@ def repack(self, zfile, removed=None):
 
         Side effects:
             - Modifies the ZIP file in place.
-            - Updates zfile.start_dir and zfile.data_offset to account for
-              removed data.
+            - Updates zfile.start_dir to account for removed data.
             - Sets zfile._didModify to True.
             - Updates header_offset and clears _end_offset of referenced
               ZipInfo instances.
@@ -283,15 +282,6 @@ def repack(self, zfile, removed=None):
         zfile.start_dir -= entry_offset
         zfile._didModify = True
 
-        # polyfill: update _data_offset if exists
-        if getattr(zfile, '_data_offset', None):
-            try:
-                offset = filelist[0].header_offset
-            except IndexError:
-                offset = zfile.start_dir
-            if offset < zfile._data_offset:
-                zfile._data_offset = offset
-
         # polyfill: clear ZipInfo._end_offset if exists
         # (Python >= 3.8 with fix #109858)
         if hasattr(ZipInfo, '_end_offset'):

tests/test_zipfile.py

@@ -985,67 +985,9 @@ def test_repack_prepended_bytes(self):
                     fh.write(b'dummy ')
                     fh.write(fz.read())
                 with zipfile.ZipFile(TESTFN, 'a', self.compression) as zh:
-                    if hasattr(zh, 'data_offset'):
-                        self.assertEqual(zh.data_offset, 6)
                     for i in ii:
                         zh.remove(self.test_files[i][0])
                     zh.repack()
-                    if hasattr(zh, 'data_offset'):
-                        self.assertEqual(zh.data_offset, 6)
-
-                    # check infolist
-                    self.assertEqual(
-                        [ComparableZipInfo(zi) for zi in zh.infolist()],
-                        [ComparableZipInfo(zi) for zi in expected_zinfos],
-                    )
-
-                # check file size
-                self.assertEqual(os.path.getsize(TESTFN), expected_size)
-
-                # make sure the zip file is still valid
-                with zipfile.ZipFile(TESTFN) as zh:
-                    self.assertIsNone(zh.testzip())
-
-    def test_repack_prepended_file_entry(self):
-        for ii in ([0], [0, 1], [0, 1, 2]):
-            with self.subTest(remove=ii):
-                # calculate the expected results
-                fz = io.BytesIO()
-                test_files = [data for j, data in enumerate(self.test_files) if j not in ii]
-                self._prepare_zip_from_test_files(fz, test_files)
-                fz.seek(0)
-                with open(TESTFN, 'wb') as fh:
-                    fh.write(b'dummy ')
-                    fh.write(fz.read())
-                with zipfile.ZipFile(TESTFN) as zh:
-                    expected_zinfos = list(zh.infolist())
-                expected_size = os.path.getsize(TESTFN)
-
-                # do the removal and check the result
-                fz = io.BytesIO()
-                with zipfile.ZipFile(fz, 'w') as zh:
-                    for j, (file, data) in enumerate(self.test_files):
-                        if j in ii:
-                            zh.writestr(file, data)
-                    fz.seek(0)
-                    prefix = fz.read()
-
-                fz = io.BytesIO()
-                test_files = [data for j, data in enumerate(self.test_files) if j not in ii]
-                self._prepare_zip_from_test_files(fz, test_files)
-                fz.seek(0)
-
-                with open(TESTFN, 'wb') as fh:
-                    fh.write(b'dummy ')
-                    fh.write(prefix)
-                    fh.write(fz.read())
-
-                with zipfile.ZipFile(TESTFN, 'a', self.compression) as zh:
-                    if hasattr(zh, 'data_offset'):
-                        self.assertEqual(zh.data_offset, 6 + len(prefix))
-                    zh.repack()
-                    if hasattr(zh, 'data_offset'):
-                        self.assertEqual(zh.data_offset, 6)
 
                     # check infolist
                     self.assertEqual(
@@ -1235,12 +1177,8 @@ def test_repack_removed_prepended_bytes(self):
                     fh.write(b'dummy ')
                     fh.write(fz.read())
                 with zipfile.ZipFile(TESTFN, 'a', self.compression) as zh:
-                    if hasattr(zh, 'data_offset'):
-                        self.assertEqual(zh.data_offset, 6)
                     zinfos = [zh.remove(self.test_files[i][0]) for i in ii]
                     zh.repack(zinfos)
-                    if hasattr(zh, 'data_offset'):
-                        self.assertEqual(zh.data_offset, 6)
 
                     # check infolist
                     self.assertEqual(