deepcopy memoryview raises TypeError
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interpreter-core
type-bug
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- Python
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Description
Bug report
Calling deepcopy on a memoryview raises a TypeError, this looks similar to bug 82474 https://github.com/python/cpython/issues/82474
This also breaks BinaryField when using Django Polymorphic
https://github.com/django-polymorphic/django-polymorphic/issues/524
Your environment
- CPython versions tested on: 3.8, 3.10
- Operating system and architecture: Ubuntu 21.10
>>> a = memoryview(b'123')
>>> from copy import deepcopy
>>> deepcopy(a)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python3.10/copy.py", line 161, in deepcopy
rv = reductor(4)
TypeError: cannot pickle 'memoryview' object
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the deepcopy path in Lib/copy.py shown by the traceback and reproduce the failure with the memoryview example on a supported CPython version. Check related issue 82474 and determine the intended deepcopy behavior for memoryview; done should include coverage for the reported case and no TypeError from deepcopy.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100