From e192a0ea521cdeac1531ddefb08df0db76c0207f Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Fri, 22 May 2026 11:46:14 +0200 Subject: [PATCH] [3.15] gh-137571: Protect against possible UnboundLocalError in gzip._GzipReader.read() (GH-150222) (GH-150229) This has not been observed in practice, but we cannot be 100% sure that it will not happen with some weird gzip data. (cherry picked from commit 28eac9a7263ad8dcfa9b536aa238549131857e0f) Co-authored-by: Serhiy Storchaka --- Lib/gzip.py | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Lib/gzip.py b/Lib/gzip.py index 8720acc4db9..0713b922522 100644 --- a/Lib/gzip.py +++ b/Lib/gzip.py @@ -610,10 +610,10 @@ def read(self, size=-1): # Read a chunk of data from the file if self._decompressor.needs_input: buf = self._fp.read(READ_BUFFER_SIZE) - uncompress = self._decompressor.decompress(buf, size) else: - uncompress = self._decompressor.decompress(b"", size) + buf = b"" + uncompress = self._decompressor.decompress(buf, size) if self._decompressor.unused_data != b"": # Prepend the already read bytes to the fileobj so they can # be seen by _read_eof() and _read_gzip_header()