fix(decode_bytes): handle multiple errors

This commit fixes an issue in multiple error
handling where parts of the input strings were
repeated in the output of `decode_bytes`.

It also adds a regreesion test to enure that
multiple encoding errors in a single input
chunk are handled properly.

datalad_next/itertools/decode_bytes.py

@@ -103,8 +103,11 @@ def handle_decoding_error(position: int,
         else:
             return (
                 position + exc.end,
-                joined_data[:position + exc.end].decode(
-                    encoding, errors='backslashreplace')
+                joined_data[position:position + exc.start].decode(encoding)
+                + joined_data[position + exc.start:position + exc.end].decode(
+                    encoding,
+                    errors='backslashreplace'
+                ),
             )
 
     joined_data = b''

datalad_next/itertools/tests/test_decode_bytes.py

@@ -35,3 +35,8 @@ def test_no_empty_strings():
     # check that empty strings are not yielded
     r = tuple(decode_bytes([b'\xc3', b'\xb6']))
     assert r == ('ö',)
+
+
+def test_multiple_errors():
+    r = ''.join(decode_bytes([b'08 War \xaf No \xaf More \xaf Trouble.shn.mp3']))
+    assert r == '08 War \\xaf No \\xaf More \\xaf Trouble.shn.mp3'