traverseda
/
cpython
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

bpo-40105: ZipFile truncate in append mode with shorter comment (GH-19337)

This commit is contained in:
Jan Mazur 2020-09-28 20:53:33 +02:00 committed by GitHub
parent a195bceff7
commit ff9147d93b
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 7 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
Lib/test/test_zipfile.py
View File

@ -1856,11 +1856,14 @@ class OtherTests(unittest.TestCase):
self.assertEqual(zipf.comment, b"an updated comment") self.assertEqual(zipf.comment, b"an updated comment")
# check that comments are correctly shortened in append mode # check that comments are correctly shortened in append mode
# and the file is indeed truncated
with zipfile.ZipFile(TESTFN,mode="w") as zipf: with zipfile.ZipFile(TESTFN,mode="w") as zipf:
zipf.comment = b"original comment that's longer" zipf.comment = b"original comment that's longer"
zipf.writestr("foo.txt", "O, for a Muse of Fire!") zipf.writestr("foo.txt", "O, for a Muse of Fire!")
original_zip_size = os.path.getsize(TESTFN)
with zipfile.ZipFile(TESTFN,mode="a") as zipf: with zipfile.ZipFile(TESTFN,mode="a") as zipf:
zipf.comment = b"shorter comment" zipf.comment = b"shorter comment"
self.assertTrue(original_zip_size > os.path.getsize(TESTFN))
with zipfile.ZipFile(TESTFN,mode="r") as zipf: with zipfile.ZipFile(TESTFN,mode="r") as zipf:
self.assertEqual(zipf.comment, b"shorter comment") self.assertEqual(zipf.comment, b"shorter comment")

2
Lib/zipfile.py
View File

@ -1918,6 +1918,8 @@ class ZipFile:
centDirSize, centDirOffset, len(self._comment)) centDirSize, centDirOffset, len(self._comment))
self.fp.write(endrec) self.fp.write(endrec)
self.fp.write(self._comment) self.fp.write(self._comment)
if self.mode == "a":
self.fp.truncate()
self.fp.flush() self.fp.flush()
def _fpclose(self, fp): def _fpclose(self, fp):

2
Misc/NEWS.d/next/Library/2020-04-03-16-13-59.bpo-40105.hfM2c0.rst Normal file
View File

@ -0,0 +1,2 @@
ZipFile truncates files to avoid corruption when a shorter comment is provided
in append ("a") mode. Patch by Jan Mazur.