Is this correct way to import python scripts residing in arbitrary folders?

Question

This snippet is from an earlier answer here on SO. It is about a year old (and the answer was not accepted). I am new to Python and I am finding the system path a real pain.

Answer 1

It does feel like a bit of a hack, but at the moment, I can't think of any unintended side effects that are likely to occur, at least not as long as you're just using this for your own scripts. Basically what it does is temporarily add the parent directory of the specified file (in your example, /home/pydev/path1/) to the list of paths that Python checks when it's looking for a module to import.

The only risk I can think of right now would arise in a multithreaded environment, where two or more threads (or processes) are running this function simultaneously. If thread A wants to import module A from path dirA/A.py, and thread B wants to import module B from path dirB/B.py, you'd wind up with both dirA and dirB in sys.path for a short time. And if there is a file named B.py in dirA, it's possible that thread B will find that (dirA/B.py) instead of the file it's looking for (dirB/B.py), thus importing the wrong module. For this reason, I wouldn't use it in production code, or code that you're going to distribute to other people (at least not without warning them that this hack is in here!). In a situation like that, you could write a more complex function that allows you to specify the file to import without messing with the standard set of paths. (That's what mod_python does, for example)