`zipfile.ZipFile.writestr()` raises `AttributeError` instead of accepting `os.PathLike` objects (e.g. `pathlib.Path`)

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
72/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Quiet
Tech stack
python
Domain
backend

Research direction

Start in zipfile/init.py at ZipFile.writestr(), ZipInfo.init(), and _sanitize_filename(), then run the pathlib.Path reproduction from the issue. Done means writestr() accepts os.PathLike objects such as pathlib.Path without raising AttributeError while retaining existing string behavior.

Written by the indexing model from the issue text.

Description

stdlib type-feature

Bug report

Bug description:

Unlike ZipFile.write() (which accepts os.PathLike objects such as pathlib.Path for both its filename and arcname arguments), ZipFile.writestr() fails when passed a PathLike object as its zinfo_or_arcname parameter.

Instead of converting it to a string using os.fspath() (as expected by modern standard library conventions), it attempts to call .find(chr(0)) directly on the path object, resulting in an immediate AttributeError.

Repro:

import zipfile
import pathlib
import io
z = zipfile.ZipFile(io.BytesIO(), 'w')
# Passes a pathlib.Path instead of a raw string
z.writestr(pathlib.Path('foo.txt'), b'hello')

Traceback:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../zipfile/__init__.py", line 2020, in writestr
    zinfo = ZipInfo(zinfo_or_arcname)._for_archive(self)
            ^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".../zipfile/__init__.py", line 455, in __init__
    filename = _sanitize_filename(filename)
  File ".../zipfile/__init__.py", line 410, in _sanitize_filename
    null_byte = filename.find(chr(0))
                ^^^^^^^^^^^^^
AttributeError: 'PosixPath' object has no attribute 'find'
CPython versions tested on:

3.14

Operating systems tested on:

macOS

Dominant language
Python
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