Patch CLI to not crash on non .gz filename

Author: rhpvorderman

src/isal/igzip.py

@@ -294,8 +294,9 @@ def main():
         in_file = IGzipFile(mode="rb", fileobj=sys.stdin.buffer)
     elif not args.compress and args.file is not None:
         base, extension = os.path.splitext(args.file)
-        if extension != ".gz":
-            sys.exit(f"filename doesn't end in .gz: {args.file!r}")
+        if extension != ".gz" and not args.stdout:
+            sys.exit(f"filename doesn't end in .gz: {args.file!r}. "
+                     f"Cannot determine output filename.")
         in_file = open(args.file, "rb")
 
     # Determine output file

tests/test_gzip_compliance.py

@@ -823,7 +823,8 @@ def test_decompress_infile_outfile(self):
     def test_decompress_infile_outfile_error(self):
         rc, out, err = assert_python_failure('-m', 'isal.igzip', '-d',
                                              'thisisatest.out')
-        self.assertEqual(b"filename doesn't end in .gz: 'thisisatest.out'",
+        self.assertEqual(b"filename doesn't end in .gz: 'thisisatest.out'. "
+                         b"Cannot determine output filename.",
                          err.strip())
         self.assertEqual(rc, 1)
         self.assertEqual(out, b'')

tests/test_igzip.py

@@ -118,6 +118,15 @@ def test_decompress_infile_outfile_error(capsysbinary):
     assert out == b''
 
 
+def test_decompress_infile_stdout_noerror(capsysbinary, tmp_path):
+    test_file = tmp_path / "test"
+    test_file.write_bytes(COMPRESSED_DATA)
+    sys.argv = ['', '-cd', str(tmp_path / 'test')]
+    igzip.main()
+    result = capsysbinary.readouterr()
+    assert DATA == result.out
+
+
 def test_decompress_infile_stdout(capsysbinary, tmp_path):
     test_gz = tmp_path / "test.gz"
     test_gz.write_bytes(gzip.compress(DATA))