Copying bytes object to shared memory list truncates trailing zeros #106939
Description
Bug report
tl;dr; See stack overflow post
When copying a bytes object to a shareable list, the trailing zeros are stripped causing data loss. This doesn't appear in the documentation as far as I can tell, and seems to be unexpected behavior related to the implementation.
Example code:
from multiprocessing import shared_memory as shm
shmList = shm.ShareableList([bytes(50)])
testBytes = bytes.fromhex("00112233445566778899aabbccddeeff0000")
shmList[0] = testBytes
print(testBytes)
print(shmList[0])
shmList.shm.close()
shmList.shm.unlink()Output:
b'\x00\x11"3DUfw\x88\x99\xaa\xbb\xcc\xdd\xee\xff\x00\x00'
b'\x00\x11"3DUfw\x88\x99\xaa\xbb\xcc\xdd\xee\xff'
Offending portion of CPython code:
_back_transforms_mapping = {
0: lambda value: value, # int, float, bool
1: lambda value: value.rstrip(b'\x00').decode(_encoding), # str
2: lambda value: value.rstrip(b'\x00'), # bytes
3: lambda _value: None, # None
}