Exception OSError in __del__ ignored

[gvalkov]

Exception OSError in __del__ ignored

[rolfmorel]

All right, I think I've got it.

In InputDevice.close() it first checks if self.fd looks like a valid file descriptor, then it calls os.close(self.fd).

The problem is if os.close(self.fd) raises an exception self.fd will still be the value which caused the exception even though the OS considers the file descriptor now closed. This in turn means that when the destructor (del) is called it will call self.close(), and the close method will consider self.fd to look valid, and because the fd is still the value which the OS has already closed os.close(self.fd) it will now generate a 'Bad file descriptor' error.

The quick hack solution:

def close(self):
    if self.fd > -1:
        fd = self.fd
        self.fd = -1

        os.close(fd)

Or the much better pythonic version (any Exception handlers keep easy access to the offending file descriptor):

def close(self):
    if self.fd > -1:
        try:
            os.close(self.fd)
        finally:
            self.fd = -1

Note that the above also fixes the 'self.fd > 0' check.

[gvalkov]

Hello. I'm very happy to hear that this project is of use to you!

I openly admit that I didn't know constructors in Python worked this way. Thanks for catching this bug and enlightening me in the process. Does the fix in 12c5751 work for you? I'll push 0.4.3 as soon as we settle this.

The fd > 0 when stdin was de-allocated thing is also a good catch. Much appreciated.

Regards,
Georgi

[rolfmorel]

Thank you for looking it over and quickly applying a fix.

Just gave 12c5751 a quick test and it looks like the erroneous behaviour is fixed and everything is working as expected.

[gvalkov]

evdev-0.4.3 pushed to pypi. Thanks again.