gh-152486: Fix force_zip64 not honored when writing central directory

Author: danny0838

Lib/test/test_zipfile/test_core.py

@@ -1243,6 +1243,22 @@ def test_force_zip64(self):
         self.assertEqual(len(zinfos), 1)
         self.assertGreaterEqual(zinfos[0].extract_version, zipfile.ZIP64_VERSION)  # requires zip64 to extract
 
+    def test_force_zip64_central(self):
+        """Test that force_zip64 is honored when writing to central directory"""
+        fh = io.BytesIO()
+        with zipfile.ZipFile(fh, 'w') as zh:
+            with zh.open('strfile', 'w', force_zip64=True) as zi:
+                pass
+
+        fh.seek(0)
+        with zipfile.ZipFile(fh, 'r') as zh:
+            zinfo = zh.getinfo('strfile')
+            self.assertEqual(zinfo.extra, (
+                b'\x01\x00\x10\x00'
+                b'\x00\x00\x00\x00\x00\x00\x00\x00'
+                b'\x00\x00\x00\x00\x00\x00\x00\x00'
+            ))
+
     def test_unseekable_zip_unknown_filesize(self):
         """Test that creating a zip with/without seeking will raise a RuntimeError if zip64 was required but not used"""
 
@@ -1448,6 +1464,11 @@ def comparable_zinfo(zinfo):
     # pretending it's always set.
     attrs['flag_bits'] |= 0x800
 
+    # Check decoded data (file size, compressed size) and ignore zip64 subfield
+    # in extra data since is may be inconsistent for a ZipInfo before writing
+    # and one read from a file.
+    attrs['extra'] = zipfile._Extra.strip(attrs['extra'], (1,))
+
     return attrs
 
 _struct_pack = struct.pack

Lib/zipfile/__init__.py

@@ -453,6 +453,7 @@ class ZipInfo:
         'file_size',
         '_raw_time',
         '_end_offset',
+        '_force_zip64',
     )
 
     def __init__(self, filename="NoName", date_time=(1980,1,1,0,0,0)):
@@ -488,6 +489,7 @@ def __init__(self, filename="NoName", date_time=(1980,1,1,0,0,0)):
         self.compress_size = 0          # Size of the compressed file
         self.file_size = 0              # Size of the uncompressed file
         self._end_offset = None         # Start of the next local header or central directory
+        self._force_zip64 = None        # Whether zip64 extension is forced
         # Other attributes are set by class ZipFile:
         # header_offset         Byte offset to the file header
         # CRC                   CRC-32 of the uncompressed file
@@ -2202,6 +2204,7 @@ def open(self, name, mode="r", pwd=None, *, force_zip64=False):
             zinfo = self.getinfo(name)
 
         if mode == 'w':
+            zinfo._force_zip64 = force_zip64
             return self._open_to_write(zinfo, force_zip64=force_zip64)
 
         if self._writing:
@@ -2646,8 +2649,10 @@ def _write_end_record(self):
             dosdate = (dt[0] - 1980) << 9 | dt[1] << 5 | dt[2]
             dostime = dt[3] << 11 | dt[4] << 5 | (dt[5] // 2)
             extra = []
-            if zinfo.file_size > ZIP64_LIMIT \
-               or zinfo.compress_size > ZIP64_LIMIT:
+            if (zinfo._force_zip64
+                or zinfo.file_size > ZIP64_LIMIT
+                or zinfo.compress_size > ZIP64_LIMIT
+            ):
                 extra.append(zinfo.file_size)
                 extra.append(zinfo.compress_size)
                 file_size = 0xffffffff