Python may startup fails if the home variable in pyvenv.cfg is inaccurate #127440
Description
Bug report
Bug description:
The problem comes from getpath.py. When getpath.py cannot find STDLIB_LANDMARKS from executable_dir, it will set prefix to the PREFIX. If the directory set in PREFIX does not exist, an error occurs.
See details:
Lines 590 to 599 in 49f15d8
How to reproduce
# 1. build cpython with prefix
./configure --prefix=/home/xx/tmp/install_dir
make
make install
# 2. copy install_dir to another
cd /home/xx/tmp
cp -r ./install_dir/ ./copy_dir
# 3. create a symlink from copy_dir/python
ln -s ./copy_dir/bin/python3 ./pylink
# 4. delete original install_dir
rm -rf ./install_dir/
# 5. use python symlink to create a venv
./pylink -m venv ./bad_venv
# 6. failed to start!
./bad_venv/bin/python3Error message
Could not find platform independent libraries <prefix>
Could not find platform dependent libraries <exec_prefix>
Python path configuration:
PYTHONHOME = (not set)
PYTHONPATH = (not set)
program name = './bad_venv/bin/python3'
isolated = 0
environment = 1
user site = 1
safe_path = 0
import site = 1
is in build tree = 0
stdlib dir = '/home/xx/tmp/install_dir/lib/python3.12'
sys._base_executable = '/home/xx/tmp/copy_dir/bin/python3.12'
sys.base_prefix = '/home/xx/tmp/install_dir'
sys.base_exec_prefix = '/home/xx/tmp/install_dir'
sys.platlibdir = 'lib'
sys.executable = '/home/xx/tmp/bad_venv/bin/python3'
sys.prefix = '/home/xx/tmp/install_dir'
sys.exec_prefix = '/home/xx/tmp/install_dir'
sys.path = [
'/home/xx/tmp/install_dir/lib/python312.zip',
'/home/xx/tmp/install_dir/lib/python3.12',
'/home/xx/tmp/install_dir/lib/python3.12/lib-dynload',
]
Fatal Python error: init_fs_encoding: failed to get the Python codec of the filesystem encoding
Python runtime state: core initialized
ModuleNotFoundError: No module named 'encodings'
We can find that sys._base_executable here is correct, but sys.base_prefix is wrong.
We could configure base_prefix through the real interpreter path, which is used to search for libraries that Python depends on.
CPython versions tested on:
3.12
Operating systems tested on:
Linux