using assume can cause crash during eval

[lukamar]

If you enter

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assume(a<b)

and then

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assume(b<a)

then trying to compute with a and b, e.g.

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a+b

causes an infinite loop, crashing after a while (stack overflow?).

[parisse]

I don't get a crash here (linux 64 bits), after 35 seconds I get a+b. Probably a stack overflow indeed, I should probably add a stack protection like MicroPython does, with a max stack size that is initialized at the begin of main() and a stack check at every evaluation.

[parisse]

I tried to add a stack check, with a limit less than 100K of stack one gets a stack overflow on your example. But then some regression tests fail (chk_limit). Therefore I will not enable this, at least not for Linux.

[lukamar]

Thanks for clearing this up. My example is quite pathological, but maybe assume should report a warning when conflicting assumptions from the user are detected.

[parisse]

Indeed, I plan to add a check for "recursive" assumptions, like for :=