ShareableList removes trailing zeroes from strings and bytes

Bug report

from multiprocessing.shared_memory import ShareableList
s, b = '\x00\x01\x00', bytes([0,1,0])
sl = ShareableList([s, b])
s == sl[0], b == sl[1]

gives (False, False) because the trailing zeroes get lost in the ShareableList: sl holds ShareableList(['\x00\x01', b'\x00\x01'], name='wnsm_...'). I would expect that strings and bytes keep the trailing zeroes also when added to a ShareableList.

Your environment

• CPython versions tested on: 3.8.5, 3.10.6
• Operating system and architecture: Windows 10, 64bit

Analysis

There are three places in class ShareableList in Lib/multiprocessing/shared_memory.py, where trailing zeroes are explicitely removed: ...rstrip(b'\x00').... For what reason?

Start in Lib/multiprocessing/shared_memory.py and inspect the three ShareableList locations using rstrip(b'\x00'); reproduce the supplied example to confirm the behavior. Done means strings and bytes retain trailing zeroes while existing ShareableList behavior remains intact, with regression coverage added where the project’s tests for this entry point belong.