pickle_loads attempts item assignment with tuple

[JSKenyon]

What happened:
I am using the main branch in order to play with annotation functionality as well as to circumvent other serialization problems. However, the changes made in #4541 seem to have broken my application. In particular,

distributed/distributed/protocol/serialize.py

Lines 70 to 84 in 98148cb

	def pickle_loads(header, frames):
	x, buffers = frames[0], frames[1:]
	writeable = header["writeable"]
	for i in range(len(buffers)):
	mv = memoryview(buffers[i])
	if writeable[i] == mv.readonly:
	if mv.readonly:
	buf = memoryview(bytearray(mv))
	else:
	buf = memoryview(bytes(mv))
	if buf.nbytes > 0:
	buffers[i] = buf.cast(mv.format, mv.shape)
	else:
	buffers[i] = buf.cast(mv.format)
	return pickle.loads(x, buffers=buffers)

triggers messages like:

File "/site-packages/distributed/protocol/serialize.py", line 78, in pickle_loads
    buffers[i] = memoryview(bytearray(mv)).cast(mv.format, mv.shape)
TypeError: 'tuple' object does not support item assignment

@madsbk could you please help me understand the specific condition that would trigger this failure?

What you expected to happen:
I expected no change - the 2021.02.0 versions don't seem to have the problem.

Minimal Complete Verifiable Example:

I don't have a specific example, rather I am fairly certain that buffers is of type tuple and item assignment will never be successful.

Environment:

• Dask version: main as of 19 March 2021
• Python version: 3.8.8
• Operating System: Pop!_OS 18.04
• Install method (conda, pip, source): pip

[quasiben]

I think this has been resolved in #4595 . Can you try latest in main ?

[JSKenyon]

I was using main from today and I believe that the PR you linked went in yesterday. I think that the issue is present before and after that merge with the original source of the problem being the PR I linked above.

…

On Fri, 19 Mar 2021, 15:34 Benjamin Zaitlen, ***@***.***> wrote: I think this has been resolved in #4595 <#4595> . Can you try latest in main ? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#4611 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABSHDWNHG3T3VJ4XI3O32H3TENHFZANCNFSM4ZOWGBGQ> .

[quasiben]

@JSKenyon the error reported looks like an older version of serialize compared to latest in main. Can you double check that latest is installed correctly ?

python -c 'import distributed;print(distributed.version)'

I have 2021.03.0+18.g98148cbf

[JSKenyon]

I just reinstalled to be extra sure and the problem has indeed gone away. Maybe I made a mistake when setting up my environment earlier (that or I somehow ended up one version behind main). Reagardless, thanks for the help @quasiben!

[quasiben]

Thanks for reporting and confirming the issue was resolved!