prefixed PYTHONPATHs not in sys.path for embedded Python

Question

In the following structure:

- foobar
  - __init__.py
  - pyfoo
    - __init__.py
    - foo.pyd
    - src
      - __init__.py
      - test
        - __init__.py
        - bar.py

I try to load foo.pyd from bar.py. Therefor I inserted an entry into PYTHONPATH with \\?\C:\<path_to_foobar>\foobar\pyfoo.

In bar.py I then try to

import foo

, which never finds foo.

Now when I look at sys.path, entries from PYTHONPATH are missing. Also, when I look under which paths foo.pyd is searched, only paths of sys.path are taken into account.

So how come sys.path does not contain all paths of PYTHONPATH?

EDIT:

To test the paths I inserted logs right before import:

print("SP %s" % sys.path)
print("PP %s" % os.environ["PYTHONPATH"])

Which gives me something like:

SP ['\\\\?\\B:\\foobar\\pyfoo\\src\\test', 'C:\\python3\\win_x86_64\\python35.zip', 'C:\\python3\\win_x86_64\\DLLs', 'C:\\python3\\win_x86_64\\lib', 'C:\\python3\\win_x86_64']
PP \\?\B:\;\\?\B:\foobar\pyfoo;\\?\B:\foobar;\\?\B:\foobar\pyfoo

how did you insert your PYTHONPATH entry? are you sure that the variable is defined where you're running your script? you may echo PYTHONPATH before starting your script. Clearly a minimal reproducible example is missing here. — Jean-François Fabre
– Jean-François Fabre ♦, Commented Feb 8, 2017 at 13:14
I understand you replaced your server name by ?. If not there's a first problem: this cannot be a valid path. And the other error is the drive : which should be $ in the case of UNC paths with drives. Your UNC paths doesn't seem valid. — Jean-François Fabre
– Jean-François Fabre ♦, Commented Feb 8, 2017 at 13:35
`\\?` is a long-path prefix on Windows. Read: msdn.microsoft.com/en-us/library/windows/desktop/… — abergmeier
– abergmeier, Commented Feb 8, 2017 at 13:56
Ok, so it's valid windows-wise. do you really need that? can you try without? — Jean-François Fabre
– Jean-François Fabre ♦, Commented Feb 8, 2017 at 14:00

Jean-François Fabre · Accepted Answer · 2017-02-08 14:28:51Z

1

Cannot reproduce your problem, with my Windows 7-x64 + python 3.4.4-x64 version it works, contents of PYTHONPATH are present in sys.path:

set PYTHONPATH=\\?\L:\SO
python

>>> import sys
>>> sys.path
['', '\\\\?\\L:\\SO', ... , 'D:\\Python34-x64\\lib\\site-packages']

That said, as a workaround, you could force the contents of PYTHONPATH into sys.path like this:

import os,sys
sys.path.extend(os.getenv("PYTHONPATH").split(os.pathsep))

# now you can import foo
import foo

edited Feb 8, 2017 at 14:28

answered Feb 8, 2017 at 14:09

Jean-François Fabre♦

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9 Comments

abergmeier Over a year ago

Can you try to call a script with prefixed path please?

abergmeier Over a year ago

What version of Windows are you using?

Jean-François Fabre Over a year ago

Windows 7 64-bit. What version of python are you using?

abergmeier Over a year ago

Python3.6 on Windows 10.

Jean-François Fabre Over a year ago

Python 3.6 is still new. You may be on to something here. Could you try with an older version by your end? (note: I edited the tags of your question to reflect python 3.6)

|

abergmeier · Accepted Answer · 2017-02-08 15:03:30Z

Trying (with 3.5.2-embeddable):

set PYTHONPATH=\\?\C:\Windows

C:\python3.5.2\win_x86_64\python.exe \\?\C:\temp\test.py

with test.py:

import os
import sys

print("SP %s" % sys.path)
print("PP %s" % os.environ["PYTHONPATH"])

Leads to \\?\C:\Windows being missing from sys.path.

Making the same test with set PYTHONPATH=C:\Windows works like a charm in 3.5.2-embeddable.

The same test with 3.6.0-embeddable does not add to sys.path in any case.

And 3.6.0-embeddable seems like the intended behavior https://bugs.python.org/issue28245

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