pyflakes gives erroneous 'undefined name'

[John L. Villalovos]

$ cat tt.py
#!/usr/bin/python -tt
import random
import sys

def main():
    f = None
    try:
        f = "bob"
        if random.choice((True, False)):
            raise Exception('test')
    except:
        del f
        raise Exception('my custom exception')
    print f

if '__main__' == __name__:
    sys.exit(main())

$ $ pyflakes tt.py
tt.py:15: undefined name 'f'

[Phil Frost (bitglue)]

Confirmed. Thanks for the report.

[Peuchele (peuchele)]

I was about to report the same issue, but with a different example. Pasting here for reference:
x = 0
while True:
    data = "dummy"
    if x == 1:
        del data
        break
    print data
    del data
    break

Real life example:
https://github.com/jelmer/dulwich/blob/master/dulwich/protocol.py#L353

[John Vandenberg (jayvdb)]

I believe these are both the same problem as https://bugs.launchpad.net/pyflakes/+bug/1308508 .