Fix issue with pack_commands returning an empty byte sequence (#2416)

Co-authored-by: dvora-h <67596500+dvora-h@users.noreply.github.com>

Author: jmcbailey

redis/asyncio/connection.py

@@ -925,7 +925,8 @@ def pack_commands(self, commands: Iterable[Iterable[EncodableT]]) -> List[bytes]
  or chunklen > buffer_cutoff
  or isinstance(chunk, memoryview)
  ):
- output.append(SYM_EMPTY.join(pieces))
+ if pieces:
+ output.append(SYM_EMPTY.join(pieces))
  buffer_length = 0
  pieces = []
 

redis/connection.py

@@ -976,7 +976,8 @@ def pack_commands(self, commands):
  or chunklen > buffer_cutoff
  or isinstance(chunk, memoryview)
  ):
- output.append(SYM_EMPTY.join(pieces))
+ if pieces:
+ output.append(SYM_EMPTY.join(pieces))
  buffer_length = 0
  pieces = []