[issue36136] Windows: python._pth sets isolated mode late during Python initialization

[STINNER Victor]

Change by STINNER Victor :


--
resolution:  -> out of date
stage:  -> resolved
status: open -> closed

___
Python tracker 

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

[issue36136] Windows: python._pth sets isolated mode late during Python initialization

[Steve Dower]

Steve Dower  added the comment:

Sorry I missed seeing this - I rarely browse new issues unless they're 
"Windows" tagged.

Reading what's in master, I don't *think* there's any regression in the main 
case, since the values from pathconfig override config and AFAICT they aren't 
used in between:

if (pathconfig.isolated != -1) {
config->isolated = pathconfig.isolated;
}

Haven't looked back at 3.7, but I haven't heard of any issues coming up here 
from people I know who have shipped this (though they might have been using 
SetPath to override it all anyway).

All of this could become irrelevant though if we add support to other platforms 
for ._pth files :) (yes, it has been requested)

--
nosy: +steve.dower

___
Python tracker 

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

[issue36136] Windows: python._pth sets isolated mode late during Python initialization

[STINNER Victor]

New submission from STINNER Victor :

The read_pth_file() of PC/getpathp.c sets Py_IsolatedFlag and Py_NoSiteFlag to 
1 in Python 3.6. calculate_path() checked if a file with a "._pth" extension 
exists in "dllpath" or "progpath".

I refactored deeply the Python initialization in Python 3.7 and I'm not sure I 
introduced a regression or not.

In Python 3.7, _PyCoreConfig_Read() calls config_init_path_config() which 
indirectly calls read_pth_file(). pymain_read_conf_impl() detects if 
Py_IsolatedFlag and Py_NoSiteFlag have been modified and store the new value in 
cmdline->isolated and cmdline->no_site_import.

Later, cmdline_set_global_config() sets Py_IsolatedFlag and Py_NoSiteFlag; and 
_PyCoreConfig_SetGlobalConfig() sets Py_IgnoreEnvironmentFlag.

The problem is the relationship between isolated/cmdline.Py_IsolatedFlag, 
no_site_import/cmdline.Py_NoSiteFlag and 
Py_IgnoreEnvironmentFlag/config.ignore_environment. The isolated mode must set 
Py_NoSiteFlag to 1 and Py_IgnoreEnvironmentFlag to 1.

For example, pymain_read_conf_impl() uses:

/* Set Py_IgnoreEnvironmentFlag for Py_GETENV() */
Py_IgnoreEnvironmentFlag = config->ignore_environment || cmdline->isolated;

But it's done before calling _PyCoreConfig_Read().

Moreover, _PyCoreConfig_Read() reads PYTHONxxx environment variables before 
calling indirectly read_pth_file(), and so PYTHONxxx env vars are read whereas 
they are supposed to be ignored.

Calling read_pth_file() earlier is challenging since it depends on 
configuration parameters which are before calling it.

At the end, I'm not sure if it's a real issue. I'm not sure if there is a 
regression in Python 3.7.

--

But the code in Python 3.8 changed a lot again: _PyCoreConfig_Read() is now 
responsible to read all environment variables.

In Python 3.8, read_pth_file() uses a _PyPathConfig structure to set isolated 
and site_import parameters. These parameters are then copied to _PyCoreConfig 
in _PyCoreConfig_CalculatePathConfig().

Moreover, _PyCoreConfig_Read() is more explicit with the relationship between 
isolated, use_environment and user_site_directory. The function *starts* with:

if (config->isolated > 0) {
config->use_environment = 0;
config->user_site_directory = 0;
}

Problems (inconsistencies) arise if isolated is set from 0 to 1 after this code.

--
components: Interpreter Core
messages: 336760
nosy: vstinner
priority: normal
severity: normal
status: open
title: Windows: python._pth sets isolated mode late during Python initialization
versions: Python 3.7, Python 3.8

___
Python tracker 

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