Steven D'Aprano <steve+pyt...@pearwood.info> added the comment:
"Undefined behaviour" has a particular meaning to C programmers, which is relevant to Python because the interpreter is written in C. It's probably best not to use that term here. Let me see if I understand your issue. * You have two separate Python processes. * Each process has a thread which dynamically writes a file called "m1.py", containing a class C. * Each process has a second thread which dynamically writes a file called "m2.py", also containing a class C. * Each thread then imports its file using the common name "M", and tries to pickle and unpickle objects of type C. * And seemingly at random, each thread sometimes picks up its class M.C, but sometimes the class M.C from the other thread. * Not sure if you get any cross-process contamination as well (that is, process 1 picks up the modules from process 2), but it wouldn't surprise me in the least. My instinct here is to back away in horror *wink* You have a lot of non-deterministic code here. I'm kinda impressed that it ever works at all :-) 1. If you have two processes writing to the same file "m1.py", its a lottery which one will end up actually written to disk. It is at least theoretically possible that the data actually on the disk could be a hybrid of bits of process 1's m1.py and bits of process 2's m1.py. 2. Likewise for the file m2.py. 3. When you go to import the files, it is non-deterministic which file you will see, e.g. - process 1 writes its m1.py - process 2 writes its m1.py, overriding the previous m1.py - process 1 goes to import m1.py, but ends up reading the m1.py created by process 2 So that's how you could get cross-process contamination. ---------- nosy: +steven.daprano title: Undefined/random behaviour when importing two modules with the same name but different source files -> Random behaviour when importing two modules with the same name but different source files _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue44916> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
