subprocess.Popen doesn't properly escape < or > for windows batch files
Open
Nobody has claimed this yet.
OS-windows
stdlib
topic-subprocess
type-bug
- Dominant language
- Python
- Stars
- 77.2k
- Forks
- 35.9k
- PR merge metrics
- PR metrics pending
Description
Bug report
Bug description:
subprocess.Popen doesn't properly escape < or > for windows batch files
example.bat
echo %*
example.py
import subprocess
from pathlib import Path
batch_file = Path().cwd() / 'example.bat'
subprocess.Popen([batch_file, 'arg1', 'arg2<99'])
Error
The system cannot find the file specified
Adding a space causes it to be correctly escaped:
subprocess.Popen([batch_file, 'arg1', 'arg2 <99'])
CPython versions tested on:
3.13
Operating systems tested on:
Windows
Linked PRs
- gh-134544
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 reported subprocess.Popen call in example.py and reproduce it on Windows with example.bat using the argument arg2<99, then compare it with the space-containing argument. Check the linked PR gh-134544 for the current state of the work; done means the no-space case is escaped correctly and the regression is covered.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- operating-systems
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 25/100