python / python/cpython

ZipFile.writestr doesn't behave like Path.write_*

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stdlib type-feature
Dominant language
Python
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Description

Feature or enhancement

Proposal:

Given that ZipPath doesn't provide a write_text or write_bytes, I'm trying to use ZipFile.writestr and noticed that when the data you're trying to write isn't the right type it still stores an empty entry. I didn't expect side effects when it failed this fundamentally to get the data.

import zipfile
with zipfile.ZipFile("foo.zip", "w") as z:
  z.writestr("x", ())
  print(z.namelist()) # -> "x"

Notably, Path.write_text behaves the way I'd expect -- it has to construct a memoryview successfully first before opening the file.

from pathlib import Path
Path("x").write_bytes(()) # -> neither creates nor truncates

@jaraco I assume ZipPath not supporting writes is intentional?

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

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Research direction

The issue names no implementation file or test. Start by reproducing the zipfile.ZipFile.writestr example and comparing it with pathlib.Path.write_bytes for invalid data; inspect the relevant standard-library implementation and tests. Done means invalid input raises without creating or truncating the archive entry.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
backend
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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