PyQt5: Changing current working directory and restoring, causes image loading bug.

enjoysmath

    if not os.path.exists(self._workDir):
        os.mkdir(self._workDir)
    curdir = QDir.currentPath()
    QDir.setCurrent(self._workDir)
    while self._renderQueue:
        queue = list(self._renderQueue)
        self._renderQueue.clear()
        for document in queue:
            self.renderDocument(document)
        self.msleep(300)
    QDir.setCurrent(curdir)

That's code of a thread that gets run before startup (and it also is used later, but new threads created).

Anyway, I'm using QSplashScreen to load an image from /images and that works normally, but only when I change working directory (and then change it back) does it fail.

My project structure is this:
[project]
|
+ images /
+ latex_svg/
+ ( main source code here in project dir)
+ ...
The above self._workDir that I change to is latex_svg. So I'm assuming the system still thinks we're in there.

I've tried both Python's os.chdir and PyQt5's QDir approach and both do the same thing.

Kent-Dorfman

you said thread, not process. different threads within an application will share the same process environment..IOW, the changing working directory is probably not thread-safe. if you truly need to do concurrent workers in different directories then either hardcode the complete paths correctly in your file operations or use instances of processes, not threads.

jsulm

@enjoysmath You should check the return value of both setCurrent() calls and print out curdir and self._workDir.

"but only when I change working directory (and then change it back) does it fail" - this is not clear to me. The first setCurrent call succeeds but the second fails?