diff options
Diffstat (limited to 'Lib')
| -rw-r--r-- | Lib/gzip.py | 3 | ||||
| -rw-r--r-- | Lib/test/test_gzip.py | 12 |
2 files changed, 15 insertions, 0 deletions
diff --git a/Lib/gzip.py b/Lib/gzip.py index cf8b675..177f908 100644 --- a/Lib/gzip.py +++ b/Lib/gzip.py @@ -401,6 +401,9 @@ class GzipFile(_compression.BaseStream): def seek(self, offset, whence=io.SEEK_SET): if self.mode == WRITE: + self._check_not_closed() + # Flush buffer to ensure validity of self.offset + self._buffer.flush() if whence != io.SEEK_SET: if whence == io.SEEK_CUR: offset = self.offset + offset diff --git a/Lib/test/test_gzip.py b/Lib/test/test_gzip.py index b06b3b0..128f933 100644 --- a/Lib/test/test_gzip.py +++ b/Lib/test/test_gzip.py @@ -665,6 +665,18 @@ class TestGzip(BaseTest): ] self.assertEqual(fc.modes, expected_modes) + def test_write_seek_write(self): + # Make sure that offset is up-to-date before seeking + # See issue GH-108111 + b = io.BytesIO() + message = b"important message here." + with gzip.GzipFile(fileobj=b, mode='w') as f: + f.write(message) + f.seek(len(message)) + f.write(message) + data = b.getvalue() + self.assertEqual(gzip.decompress(data), message * 2) + class TestOpen(BaseTest): def test_binary_modes(self): |