[with patch; positive review] scripts do not exit with correct exit code when sys.exit() is used

[ddrake]

If I call sys.exit() from a Sage script, the script exits but not with the correct exit code. For example, the script

import sys

print 'exiting!'
sys.exit(1)

exits with exit code 0 when run from Sage:

$ sage exitcode.sage 
exiting!
1
$ echo $?
0

(the 1 gets printed because the preparser turns it into a Sage integer, and Python prints out anything except Python integers.) But the same script works properly when run from Python:

$ python exitcode.sage
exiting!
$ echo $?
1

I don't know if this is Sage or IPython behavior, but having this work would be really useful.

[rlm]

+1

was showed me this patch working in all the permutations of inputs... Looks good to me.

[mabshoff]

Merged in Sage 3.3.alpha2

[ddrake]

I was going to reopen this ticket, but instead I'll leave this comment as warning to anyone else trying to use this:

If you do sys.exit(0) in a Sage script, because of preparsing, you effectively get sys.exit(Integer(0)), which results in the script exiting with code 1! This is not what anyone would expect! This is because of ​how sys.exit works when given non-Python-integer arguments. To make sure that you get the desired behavior, use int inside the call to get a Python integer: sys.exit(int(2)) or whatever.