[issue44406] Divergent sys.prefix behavior causes `python -m build` command to fail when in virtual environment

[Paul Moore]

Paul Moore  added the comment:

I don't inderstand what "discrepancy" you mean here. The documentation you 
quote explains the behaviour, and I don't see the problem.

If build is failing, why do you not think that is a bug in build? I can only 
see one call to venv.EnvBuilder in the code you mention and it looks correct. 
What error are you seeing?

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue44406] Divergent sys.prefix behavior causes `python -m build` command to fail when in virtual environment

[Dylan]

New submission from Dylan :

Confirmed on 3.6 and 3.9.  The issue can be found in venv\__init__.py where the 
sys.prefix is used to determine the parent path of the python executable (near 
the bottom of the symlink_or_copy method at about line 190).  On the venv 
documentation page (https://docs.python.org/3/library/venv.html), it is noted 
that:


When a virtual environment is active (i.e., the virtual environment’s Python 
interpreter is running), the attributes sys.prefix and sys.exec_prefix point to 
the base directory of the virtual environment, whereas sys.base_prefix and 
sys.base_exec_prefix point to the non-virtual environment Python installation 
which was used to create the virtual environment. If a virtual environment is 
not active, then sys.prefix is the same as sys.base_prefix and sys.exec_prefix 
is the same as sys.base_exec_prefix (they all point to a non-virtual 
environment Python installation).


This code is called by lib\site-packages\build\env.py (venv.EnvBuilder...) 
which fails erroneously due to the divergent behavior of the sys.prefix as 
described in the documentation snippet above.

Recommended fix:  I'm not sure why that behavior diverges in the first place.  
Ideally, either the build lib\venv\__init__.py should be updated to not rely on 
sys.prefix, or the sys.prefix behavior should be changed.

Additional Notes:
- I am seeing this issue on Windows 10
- The venv instance is within an Anaconda directory.
- The python -m build command I am running is from within a virtual environment
- I've listed file paths in relation to the library path within the same 
directory as the python executable for convenience.  Let me clarify, however, 
that there are multiple instances of the python lib folder: 1 global and 1 
local copy.  The venv path is located in the global instance within the 
Anaconda path whereas the build script is using the virtual environment 
instance of python.

--
assignee: docs@python
components: Build, Documentation, Windows
messages: 395721
nosy: docs@python, dsmaccy, paul.moore, steve.dower, tim.golden, zach.ware
priority: normal
severity: normal
status: open
title: Divergent sys.prefix behavior causes `python -m build` command to fail 
when in virtual environment
versions: Python 3.6, Python 3.9

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com