Issue #27517: LZMA compressor and decompressor no longer raise exceptions if

given empty data twice.  Patch by Benjamin Fogle.

1 files changed, 38 insertions, 0 deletions

diff --git a/Lib/test/test_lzma.py b/Lib/test/test_lzma.py
index fdc8e11f63..d7a8576d51 100644
--- a/Lib/test/test_lzma.py
+++ b/Lib/test/test_lzma.py
@@ -137,6 +137,21 @@ class CompressorDecompressorTestCase(unittest.TestCase):
         self.assertTrue(lzd.eof)
         self.assertEqual(lzd.unused_data, b"")
 
+    def test_decompressor_chunks_empty(self):
+        lzd = LZMADecompressor()
+        out = []
+        for i in range(0, len(COMPRESSED_XZ), 10):
+            self.assertFalse(lzd.eof)
+            out.append(lzd.decompress(b''))
+            out.append(lzd.decompress(b''))
+            out.append(lzd.decompress(b''))
+            out.append(lzd.decompress(COMPRESSED_XZ[i:i+10]))
+        out = b"".join(out)
+        self.assertEqual(out, INPUT)
+        self.assertEqual(lzd.check, lzma.CHECK_CRC64)
+        self.assertTrue(lzd.eof)
+        self.assertEqual(lzd.unused_data, b"")
+
     def test_decompressor_chunks_maxsize(self):
         lzd = LZMADecompressor()
         max_length = 100
@@ -274,6 +289,16 @@ class CompressorDecompressorTestCase(unittest.TestCase):
         lzd = LZMADecompressor(lzma.FORMAT_RAW, filters=FILTERS_RAW_4)
         self._test_decompressor(lzd, cdata, lzma.CHECK_NONE)
 
+    def test_roundtrip_raw_empty(self):
+        lzc = LZMACompressor(lzma.FORMAT_RAW, filters=FILTERS_RAW_4)
+        cdata = lzc.compress(INPUT)
+        cdata += lzc.compress(b'')
+        cdata += lzc.compress(b'')
+        cdata += lzc.compress(b'')
+        cdata += lzc.flush()
+        lzd = LZMADecompressor(lzma.FORMAT_RAW, filters=FILTERS_RAW_4)
+        self._test_decompressor(lzd, cdata, lzma.CHECK_NONE)
+
     def test_roundtrip_chunks(self):
         lzc = LZMACompressor()
         cdata = []
@@ -284,6 +309,19 @@ class CompressorDecompressorTestCase(unittest.TestCase):
         lzd = LZMADecompressor()
         self._test_decompressor(lzd, cdata, lzma.CHECK_CRC64)
 
+    def test_roundtrip_empty_chunks(self):
+        lzc = LZMACompressor()
+        cdata = []
+        for i in range(0, len(INPUT), 10):
+            cdata.append(lzc.compress(INPUT[i:i+10]))
+            cdata.append(lzc.compress(b''))
+            cdata.append(lzc.compress(b''))
+            cdata.append(lzc.compress(b''))
+        cdata.append(lzc.flush())
+        cdata = b"".join(cdata)
+        lzd = LZMADecompressor()
+        self._test_decompressor(lzd, cdata, lzma.CHECK_CRC64)
+
     # LZMADecompressor intentionally does not handle concatenated streams.
 
     def test_decompressor_multistream(self):