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| author | Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> | 2020-09-28 13:18:47 -0700 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-09-28 13:18:47 -0700 |
| commit | 048f54dc75d51e8a1c5822ab7b2828295192aaa5 (patch) | |
| tree | f3b118cee6c58f5074c4ab748044d6ff449e1e8e | |
| parent | bdf46bc7e12c08aaab676a2c947f03daffe035a7 (diff) | |
| download | cpython-git-048f54dc75d51e8a1c5822ab7b2828295192aaa5.tar.gz | |
bpo-40105: ZipFile truncate in append mode with shorter comment (GH-19337)
(cherry picked from commit ff9147d93b868f0e13b9fe14e2a76c2879f6787b)
Co-authored-by: Jan Mazur <16736821+mzr@users.noreply.github.com>
| -rw-r--r-- | Lib/test/test_zipfile.py | 3 | ||||
| -rw-r--r-- | Lib/zipfile.py | 2 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2020-04-03-16-13-59.bpo-40105.hfM2c0.rst | 2 |
3 files changed, 7 insertions, 0 deletions
diff --git a/Lib/test/test_zipfile.py b/Lib/test/test_zipfile.py index b7bc218d17..999197a0e3 100644 --- a/Lib/test/test_zipfile.py +++ b/Lib/test/test_zipfile.py @@ -1855,11 +1855,14 @@ class OtherTests(unittest.TestCase): self.assertEqual(zipf.comment, b"an updated comment") # check that comments are correctly shortened in append mode + # and the file is indeed truncated with zipfile.ZipFile(TESTFN,mode="w") as zipf: zipf.comment = b"original comment that's longer" 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: zipf.comment = b"shorter comment" + self.assertTrue(original_zip_size > os.path.getsize(TESTFN)) with zipfile.ZipFile(TESTFN,mode="r") as zipf: self.assertEqual(zipf.comment, b"shorter comment") diff --git a/Lib/zipfile.py b/Lib/zipfile.py index 915698f9e0..816f8582bb 100644 --- a/Lib/zipfile.py +++ b/Lib/zipfile.py @@ -1918,6 +1918,8 @@ class ZipFile: centDirSize, centDirOffset, len(self._comment)) self.fp.write(endrec) self.fp.write(self._comment) + if self.mode == "a": + self.fp.truncate() self.fp.flush() def _fpclose(self, fp): diff --git a/Misc/NEWS.d/next/Library/2020-04-03-16-13-59.bpo-40105.hfM2c0.rst b/Misc/NEWS.d/next/Library/2020-04-03-16-13-59.bpo-40105.hfM2c0.rst new file mode 100644 index 0000000000..f71a7a1e69 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-04-03-16-13-59.bpo-40105.hfM2c0.rst @@ -0,0 +1,2 @@ +ZipFile truncates files to avoid corruption when a shorter comment is provided +in append ("a") mode. Patch by Jan Mazur. |