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Description
Bug report
This comes from a recently discovered SymPy issue:sympy/sympy#23690
The following code fails in CPython 3.10 or newer for large N apparently due to the changes in#25403 (CC@markshannon):
#!/usr/bin/env python3template="""\def %(name)s(A, B): (%(A)s,) = A (%(B)s,) = B return (%(AB)s,)"""defmake_function(N):name="monomial_mul"A= [f"a{i}"foriinrange(N)]B= [f"b{i}"foriinrange(N)]AB= ["%s + %s"% (a,b)fora,binzip(A,B) ]code=template%dict(name=name,A=", ".join(A),B=", ".join(B),AB=", ".join(AB))ns= {}exec(code,ns)returnns["monomial_mul"]if__name__=="__main__":fromsysimportargvmake_function(int(argv[1]))
In CPython 3.9 or older this can run fine albeit slow for large values ofN (I tested 100000).
With CPython 3.10 or current main (3.11b3) this will fail with SystemError for anyN greater than 3000:
$./python test.py 3000$./python test.py 3001Traceback (most recent call last): File "/home/oscar/current/sympy/cpython/test.py", line 22, in <module> make_function(int(argv[1])) File "/home/oscar/current/sympy/cpython/test.py", line 17, in make_function exec(code, ns)SystemError: excessive stack use: stack is 3001 deep
I wasn't sure that this was a deliberate effect of the changes or if it should definitely be considered a bug but the comment added in#25403 indicates that it should be:
Lines 49 to 71 inc0453a4
| /* A soft limit for stack use, to avoid excessive | |
| * memory use for large constants, etc. | |
| * | |
| * The value 30 is plucked out of thin air. | |
| * Code that could use more stack than this is | |
| * rare, so the exact value is unimportant. | |
| */ | |
| #defineSTACK_USE_GUIDELINE 30 | |
| /* If we exceed this limit, it should | |
| * be considered a compiler bug. | |
| * Currently it should be impossible | |
| * to exceed STACK_USE_GUIDELINE * 100, | |
| * as 100 is the maximum parse depth. | |
| * For performance reasons we will | |
| * want to reduce this to a | |
| * few hundred in the future. | |
| * | |
| * NOTE: Whatever MAX_ALLOWED_STACK_USE is | |
| * set to, it should never restrict what Python | |
| * we can write, just how we compile it. | |
| */ | |
| #defineMAX_ALLOWED_STACK_USE (STACK_USE_GUIDELINE * 100) |
Your environment
Tested on Ubuntu with a range of Python versions.