[BUG] pyximport is ignoring sys.path

[matusvalo]

Describe your issue

Consider following file tree:

########## mydir/mytest.pyx ##########
print('Hello world!')

Running command:

PYTHONPATH=mydir python -c 'import pyximport; pyximport.install(); import mytest'

from parent directory of mydir will fail with following error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'mytest'

Expected behaviour

Compilation success since the module is present in PYTHONPATH.

OS

any

Python version

any

Cython version

master

Additional context

This bug is regression. Cython 0.29.X works correctly.

[jeremysanders]

A workaround hack is to import from the old version _pyximport2 for all python versions, e.g.

import pyximport._pyximport2 as pyximport
pyximport.install()

This is a pretty bad bug, however.