import os
import sys

# rm -r impdir; python3 thisfile.py       # fail
# rm -r impdir; python3 thisfile.py fix1  # success
# rm -r impdir; python3 thisfile.py fix2  # success

# rm -r impdir; python3 thisfile.py  # fail
# python3 thisfile.py                # success

FIX1 = 'fix1' in sys.argv
FIX2 = 'fix2' in sys.argv

if FIX1:
    import tarfile # with this here the import works

LIBDIR = 'impdir'

def extract():
    if not FIX1:
        import tarfile # with this here the import fails
    os.mkdir(LIBDIR)
    open(os.path.join(LIBDIR, 'impfile.py'), 'w')

if not FIX2:
    sys.path.append(LIBDIR) # with this here the import fails

if os.path.exists(LIBDIR):
    print('%s already exists' % LIBDIR)
else:
    extract()

if FIX2:
    sys.path.append(LIBDIR) # with this here the import works

import impfile  # <------ this is the import that fails
print('Imported impfile')