gh-132983: Don't allow trailer data in ZstdFile (#133736)

Rogdham · web-flow · commit 50b53706646c · 2025-05-10T03:32:22.000+01:00
diff --git a/Lib/compression/zstd/_zstdfile.py b/Lib/compression/zstd/_zstdfile.py
@@ -89,7 +89,6 @@ def __init__(self, file, /, mode="r", *,
             raw = _streams.DecompressReader(
                 self._fp,
                 ZstdDecompressor,
-                trailing_error=ZstdError,
                 zstd_dict=zstd_dict,
                 options=options,
             )
diff --git a/Lib/test/test_zstd.py b/Lib/test/test_zstd.py
@@ -1682,10 +1682,10 @@ def test_read_incomplete(self):
 
         # Trailing data isn't a valid compressed stream
         with ZstdFile(io.BytesIO(self.FRAME_42 + b'12345')) as f:
-            self.assertEqual(f.read(), self.DECOMPRESSED_42)
+            self.assertRaises(ZstdError, f.read)
 
         with ZstdFile(io.BytesIO(SKIPPABLE_FRAME + b'12345')) as f:
-            self.assertEqual(f.read(), b'')
+            self.assertRaises(ZstdError, f.read)
 
     def test_read_truncated(self):
         # Drop stream epilogue: 4 bytes checksum

Original file line number	Diff line number	Diff line change
`@@ -89,7 +89,6 @@ def __init__(self, file, /, mode="r", *,`
`89`	`89`	`raw = _streams.DecompressReader(`
`90`	`90`	`self._fp,`
`91`	`91`	`ZstdDecompressor,`
`92`		`- trailing_error=ZstdError,`
`93`	`92`	`zstd_dict=zstd_dict,`
`94`	`93`	`options=options,`
`95`	`94`	`)`