How does Python handle infinite recursion?

Question

So when toying with Python, I noticed that there is basically no limit on the program's stack size (kept performing power operations on a number, the precision stayed perfect even after getting to like thousands of digits). This makes me wonder: what if I accidentally got into an infinite recursive loop in Python? Would the compiler notice and throw a stack overflow error? Or would the program just crash? Would my CPU combust? This isn't something that I'd be eager to test myself, honestly.

Answer 1

No modern computer is going to combust due to user code, I promise. Try it for yourself:

def recurseInfinitely( n ):
    recurseInfinitely(n+1)

recurseInfinitely(0)

Running this program promptly yields the output:

  [...]
    recurseInfinitely(n+1)
  File "so.py", line 2, in recurseInfinitely
    recurseInfinitely(n+1)
  File "so.py", line 2, in recurseInfinitely
    recurseInfinitely(n+1)
RuntimeError: maximum recursion depth exceeded   

You can catch the error and check the value of n:

def recurseInfinitely( n ):   
    try:
        recurseInfinitely(n+1)
    except RuntimeError:
        print "We got to level %s before hitting the recursion limit."%n

And get:

We got to level 997 before hitting the recursion limit.