fix: Add tests, try to avoid UB in math helpers #4574
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junggjo9
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Aug 22, 2025
| @@ -27,17 +33,10 @@ constexpr T abs(const T n) { | |||
| /// @brief Calculates the ordinary power of the number x. | |||
| /// @param x: Number to take the power from | |||
| /// @param p: Power to take | |||
| template <typename T, std::integral P> | |||
| template <typename T, std::unsigned_integral P> | |||
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Do we really want to remove the possibility to have pow(x, -1)?
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I remember, no we need to allow for negative exponents. For example, in the Chebychev polynomials
, this expression can have a negative exponentThere was a problem hiding this comment.
Right, but the way this is implemented, negative exponents are not safe, and can easily pop over into UB. I've found it to even segfault (probably due to stack overflow) with a negative exponent and a sufficiently small base.
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Concretely, I got it to segfault on pow(1e-300, -1). At the very least, I would like to add a runtime check that the base is not too small.
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There's a lot of very easily triggered UB in
MathHelpers.hpp. This PR tries to avoid some of it, and cover it with tests.--- END COMMIT MESSAGE ---
Disclosure: some help in the tests from Claude.
@junggjo9