sys.settecursionlimit won't change from the default value of 256

[Wizardofozzie]

I'm getting an Exception RECURSION ERROR which is due to the default value being 256; ie sys.getrecursionlimit() = 256

The only way to remedy this is by prepending sys.settecursionlimit(512) so the line of code reads sys.settecursionlimit(512); foo()

Normally the sys.settecursionlimit function will change the default value (ie on windows), but in the console, it'll return the default 256 on the next line for sys.getrecursionlimit()

How can I work around this issue?

[ccc]

I am able to replicate. This only happens in the Pythonista console, NOT in Pythonista programs. The workaround is:

def my_workaround():
    sys.setrecursionlimit(512)
    foo()
    print(sys.getrecursionlimit())

my_workaround()

The behavior that you are seeing is an artifact of the Pythonista console which needs to compensate for the fact that Apple only allows iOS apps to have a single thread of execution. When you are not feeding a constant set of commands into the console, it seems to reset some of its values including recursion limit. By defining a function (or a series of ;-separated commands), you keep the console from doing that reset until after your function returns.

To see the behavior clearly, check out:

import sys

def recursion_gsg(x):
    print(sys.getrecursionlimit())
    sys.setrecursionlimit(x)
    print(sys.getrecursionlimit())
    
def recursion_test():
    orig = sys.getrecursionlimit()
    print('=' * 10)
    recursion_gsg(350)
    recursion_gsg(512)
    recursion_gsg(1024)
    recursion_gsg(orig)
    
recursion_test()

If you type that line-by-line into the Pythonista console then you get the expected output:

==========
300
350
350
512
512
1024
1024
300

However, if you now type in each line of recursion_test() into the console as a unique command, you get:

==========
300
350
300
512
300
1024
300
300

[Wizardofozzie]

FANTASTIC answer!

First off, your default is 300? I'm on iPad Air iOS 8.3. Why is mine 256?

I'll need time to digest this, but I'll play around with it now:)

[ccc]

I think mine is 300 because I am running the current beta version of Pythonista.

[Wizardofozzie]

Beta? Huh! Any idea when the release is going to be? Just curious

[ccc]

Nope. When it is ready and not before I hope.