changeset:   83200:f78d2605f452
branch:      3.3
parent:      83194:4d8e9c5ba651
user:        Serhiy Storchaka <storchaka@gmail.com>
date:        Mon Apr 08 22:35:02 2013 +0300
files:       Lib/gzip.py Lib/test/test_gzip.py Misc/NEWS
description:
Close #17666: Fix reading gzip files with an extra field.


diff -r 4d8e9c5ba651 -r f78d2605f452 Lib/gzip.py
--- a/Lib/gzip.py	Mon Apr 08 12:59:30 2013 +0300
+++ b/Lib/gzip.py	Mon Apr 08 22:35:02 2013 +0300
@@ -302,7 +302,8 @@
 
         if flag & FEXTRA:
             # Read & discard the extra field, if present
-            self._read_exact(struct.unpack("<H", self._read_exact(2)))
+            extra_len, = struct.unpack("<H", self._read_exact(2))
+            self._read_exact(extra_len)
         if flag & FNAME:
             # Read and discard a null-terminated string containing the filename
             while True:
diff -r 4d8e9c5ba651 -r f78d2605f452 Lib/test/test_gzip.py
--- a/Lib/test/test_gzip.py	Mon Apr 08 12:59:30 2013 +0300
+++ b/Lib/test/test_gzip.py	Mon Apr 08 22:35:02 2013 +0300
@@ -403,6 +403,13 @@
             with gzip.GzipFile(fileobj=io.BytesIO(truncated[:i])) as f:
                 self.assertRaises(EOFError, f.read, 1)
 
+    def test_read_with_extra(self):
+        # Gzip data with an extra field
+        gzdata = (b'\x1f\x8b\x08\x04\xb2\x17cQ\x02\xff'
+                  b'\x05\x00Extra'
+                  b'\x0bI-.\x01\x002\xd1Mx\x04\x00\x00\x00')
+        with gzip.GzipFile(fileobj=io.BytesIO(gzdata)) as f:
+            self.assertEqual(f.read(), b'Test')
 
 class TestOpen(BaseTest):
     def test_binary_modes(self):
diff -r 4d8e9c5ba651 -r f78d2605f452 Misc/NEWS
--- a/Misc/NEWS	Mon Apr 08 12:59:30 2013 +0300
+++ b/Misc/NEWS	Mon Apr 08 22:35:02 2013 +0300
@@ -21,6 +21,8 @@
 Library
 -------
 
+- Issue #17666: Fix reading gzip files with an extra field.
+
 - Issue #17502: Process DEFAULT values in mock side_effect that returns iterator.
   Patch by Michael Foord.