python / python/cpython

ZoneInfo object raises OSError instead of ZoneInfoNotFoundError for timezone input larger than 255 characters

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stdlib type-bug
Dominant language
Python
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Description

Bug report

According to documentation all calls to ZoneInfo should raise ValueError or ZoneInfoNotFoundError.
Creating a ZoneInfo object with an invalid very long timezone (length > 255) an OSError is raised instead (OSError: [Errno 36] File name too long).

I believe that https://github.com/python/cpython/blob/29f1b0bb1ff73dcc28f0ca7e11794141b6de58c9/Lib/zoneinfo/_common.py#L11-L24 should also handle the OSError exception raised by open and reraise it to ZoneInfoNotFoundError.

Sample code for reproduction:

from zoneinfo import ZoneInfo
ZoneInfo("a"*256)

Your environment

  • CPython versions tested on: Python 3.10.4
  • Operating system and architecture: Debian GNU/Linux 11 (bullseye)
Linked PRs
  • gh-99602

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start in Lib/zoneinfo/_common.py at the referenced open call and reproduce the issue with ZoneInfo("a"*256). Check the existing exception behavior for invalid timezone inputs, then verify that the long input produces the documented exception rather than OSError. Linked PR gh-99602 indicates that work is already underway.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
backend
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
20/100

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