sys.orig_argv is not original, at least on some systems #125006

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1. vstinner commented on Oct 5, 2024

   

   vstinner

   on Oct 5, 2024

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   I cannot reproduce the issue on Linux.

   $ python3 -m venv env
   $ env/bin/python -c 'import sys; print(sys.orig_argv[0])'
   env/bin/python
   
   $ source env/bin/activate
   (env) $ python -c 'import sys; print(sys.orig_argv[0])'
   python
   
   (env) $ which python
   ~/env/bin/python
   (env) $ ls -l env/bin/python
   lrwxrwxrwx 1 vstinner vstinner 7  5 oct.  22:31 env/bin/python -> python3*
   (env) $ ls -l env/bin/python3
   lrwxrwxrwx 1 vstinner vstinner 16  5 oct.  22:31 env/bin/python3 -> /usr/bin/python3*
   

   You can also have a look at:

   (env) vstinner@mona$ python
   >>> import sys
   >>> sys.executable
   '/home/vstinner/env/bin/python'
   >>> sys._base_executable
   '/usr/bin/python3.12'
   
2. pkit commented on Oct 5, 2024

   

   pkit

   on Oct 5, 2024

   Last edited by pkit

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   Yup. As I've said it's probably OSX-specific

   This one is inside venv:

   % python -c 'import sys; print(sys.orig_argv[0])'
   /opt/homebrew/Cellar/[email protected]/3.11.10/Frameworks/Python.framework/Versions/3.11/Resources/Python.app/Contents/MacOS/Python
   

   % python -c 'import sys; print(sys.executable, sys._base_executable)'
   /Users/user/git/project/.venv/bin/python /opt/homebrew/Cellar/[email protected]/3.11.10/Frameworks/Python.framework/Versions/3.11/bin/python3.11
   
3. pkit commented on Oct 7, 2024

   

   pkit

   on Oct 7, 2024

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   sys.executable works well on both Linux and OSX
   So, to correctly re-exec in a cross-platform way:

   os.execve(sys.executable, sys.orig_argv, os.environ.copy())
   
4. JacobCoffee commented on Oct 10, 2024

   

   JacobCoffee

   on Oct 10, 2024

   Member

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   here's my side

   Details

   ~ on ☁  (us-east-2)
   ➜ ntp 125006
   Directory /tmp/testing/125006 created and switched to.
   
   /tmp/testing/125006 on ☁  (us-east-2)
   ➜ python3 -m venv venv
   
   /tmp/testing/125006 on ☁  (us-east-2) took 2s
   ➜ env/bin/python -c 'import sys; print(sys.orig_argv[0])'^C
   
   /tmp/testing/125006 on ☁  (us-east-2) took 2s
   ➜ ./venv/bin/python -c 'import sys; print(sys.orig_argv[0])'
   ./venv/bin/python
   
   /tmp/testing/125006 on ☁  (us-east-2)
   ✗ source venv/bin/activate.fish
   
   /tmp/testing/125006 via  pyenv (venv) on ☁  (us-east-2)
   ➜ which python
   /private/tmp/testing/125006/venv/bin/python
   
   /tmp/testing/125006 via  pyenv (venv) on ☁  (us-east-2)
   ➜ ls -l venv/bin/python
   lrwxr-xr-x@ - coffee 10 Oct 15:59 venv/bin/python -> python3
   
   /tmp/testing/125006 via  pyenv (venv) on ☁  (us-east-2)
   ➜ ls -l venv/bin/python3
   lrwxr-xr-x@ - coffee 10 Oct 15:59 venv/bin/python3 -> /Users/coffee/.local/share/mise/installs/python/3.12/bin/python3
   
   /tmp/testing/125006 via  pyenv (venv) on ☁  (us-east-2)
   ➜ ./venv/bin/python -c 'import sys; print(sys.orig_argv[0])'
   
   ./venv/bin/python
   
   /tmp/testing/125006 via  pyenv (venv) on ☁  (us-east-2)
   ➜ python -c 'import sys; print(sys.executable, sys._base_executable)'
   /private/tmp/testing/125006/venv/bin/python3 /Users/coffee/.local/share/mise/installs/python/3.12/bin/python3.12
   
   /tmp/testing/125006 via  pyenv (venv) on ☁  (us-east-2)
   ➜ python -c 'import sys; print(sys.orig_argv[0])'
           python3
   
   /tmp/testing/125006 via  pyenv (venv) on ☁  (us-east-2)
   ➜ python -c 'import sys; print(sys.orig_argv[0])'
   python
   
5. JacobCoffee

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   OS-mac

   on Oct 10, 2024
6. ronaldoussoren commented on Dec 18, 2025

   

   ronaldoussoren

   on Dec 18, 2025

   Contributor

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   The difference between macOS framework builds (such as our installer) and other platforms is that sys.executable is a small stub that execv-s the real interpreter that's in an embedded app bundle. Reason for that is that some system APIs, and in particular GUI frameworks, assume they are only used from app bundles.

   It is probably possible to ensure sys.orig_argv[0], but getting this right in all cases including embedding in other applications is non trivial. The current behaviour is also already 5 years old at this time (the PR linked to is from 2025), which means there's a risk that changing behaviour here will break other code...

   IMHO we should change the code here, although adding a note to the documentation about not using sys.executable instead of sys.orig_argv[0] could be helpful.