I have an application that relies on SIGINT for a graceful shutdown. I noticed that every once in awhile it just keeps running. The cause turned out to be a generator in xml/etree/ElementTree.py.
If SIGINT arrives while that generator is being cleaned up, all exceptions are ignored (recall that default action for SIGINT is to raise a KeyboardInterrupt). That's not unique to this particular generator, or to generators in general.
From the python docs:
"Due to the precarious circumstances under which
__del__()methods are invoked, exceptions that occur during their execution are ignored, and a warning is printed to sys.stderr instead"
In over five years of programming in python, this is the first time I run into this issue.
If garbage collection can occur at any point, then SIGINT can also theoretically be ignored at any point, and I can't ever rely on it. Is that correct? Have I just been lucky this whole time?
Or is it something about this particular package and this particular generator?