In this test, I create a new directory (deleting it if it already exists), add it to sys.path, add two simple Python files, and try to import them. I’m using Python 3.11.6.

import sys
from pathlib import Path
from shutil import rmtree

d = Path('/tmp/fleen')
rmtree(d)
d.mkdir()
sys.path = [str(d)] + sys.path

(d / 'module1.py').write_text('x = 1')
import module1
assert module1.x == 1

(d / 'module2.py').write_text('x = 2')
print('file contains:', repr((d / 'module2.py').read_text()))
import module2
assert module2.x == 2

This prints file contains: 'x = 2', as expected, but then raises

Traceback (most recent call last):
  File "example.py", line 16, in <module>
    import module2
ModuleNotFoundError: No module named 'module2'

What’s going on? Why can’t import see the file? Is there some sort of cache of each directory in sys.path that I need to clear?