New submission from Mustafa Quraish :
The code attached produces weird behaviour on macOS (Catalina at least) on
Python3.8 / Python3.9. Issue has been reproduced on at least one other mac
belonging to a friend. Does not occur on Linux as far as I have tested. I have
simplified the code as much as I can, so the example attached does not actually
need to use parallelism.
Code description: Read text from a file, change directory using `os.chdir`,
spawn 5 processes and pass the `print` function as the handler along with the
text.
Expectation: File contents should be printed 5 times
Result: Code tries to load (again) the file in each thread, but fails since the
directory was changed.
Precondition: Have `file.txt` in the same directory containing some text
Output when run on Python3.7, I get the following (expected output):
```
Reading file...
Text loaded was: 'file contents'
file contents
file contents
file contents
file contents
file contents
```
When running on 3.8 / 3.9 (on a mac) I get the following:
```
Reading file...
Text loaded was: 'file contents'
Error: /Users/mustafa/dev/ptest/test_dir/file.txt does not exist.
Error: /Users/mustafa/dev/ptest/test_dir/file.txt does not exist.
Error: /Users/mustafa/dev/ptest/test_dir/file.txt does not exist.
```
It seems to me that even opened `file.txt` is loaded in the main thread and
text is read from it, this value isn't passed into the spawned processes and
they are calling `load()` again (which is where the error message is produced).
--
components: macOS
files: test.py
messages: 380483
nosy: bquinlan, mustafaquraish, ned.deily, pitrou, ronaldoussoren
priority: normal
severity: normal
status: open
title: Inconsistent ProcessPoolExecutor behaviour on macOS between 3.7 and 3.8/9
type: behavior
versions: Python 3.8
Added file: https://bugs.python.org/file49579/test.py
___
Python tracker
<https://bugs.python.org/issue42281>
___
___
Python-bugs-list mailing list
Unsubscribe:
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
