#19395: Raise exception when pickling a (BZ2|LZMA)(Compressor|Decompressor).

The underlying C libraries provide no mechanism for serializing compressor and
decompressor objects, so actually pickling these classes is impractical.
Previously, these objects would be pickled without error, but attempting to use
a deserialized instance would segfault the interpreter.

1 files changed, 9 insertions, 0 deletions

diff --git a/Lib/test/test_lzma.py b/Lib/test/test_lzma.py
index a13cf3bd09..ad9045604e 100644
--- a/Lib/test/test_lzma.py
+++ b/Lib/test/test_lzma.py
@@ -1,5 +1,6 @@
 from io import BytesIO, UnsupportedOperation
 import os
+import pickle
 import random
 import unittest
 
@@ -216,6 +217,14 @@ class CompressorDecompressorTestCase(unittest.TestCase):
         finally:
             input = cdata = ddata = None
 
+    # Pickling raises an exception; there's no way to serialize an lzma_stream.
+
+    def test_pickle(self):
+        with self.assertRaises(TypeError):
+            pickle.dumps(LZMACompressor())
+        with self.assertRaises(TypeError):
+            pickle.dumps(LZMADecompressor())
+
 
 class CompressDecompressFunctionTestCase(unittest.TestCase):