fix(vm): range-check magnitude before the long long cast in value_to_string (#695)#698
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InauguralPhysicist merged 1 commit intoJul 24, 2026
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…string (InauguralSystems#695) value_to_string's VAL_NUM case tested `n == (long long)n && fabs(n) < 2^53`, evaluating the `(long long)n` cast (the left conjunct) before the magnitude guard. For |n| >= 2^63 that float-to-long-long conversion is undefined behavior (float-cast-overflow, flagged by UBSan/CodeQL). Swap the conjuncts so the range check short-circuits and guards the cast; behavior for in-range values is unchanged. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Fixes #695.
value_to_string'sVAL_NUMcase hadn == (long long)n && fabs(n) < 9007199254740992.0, so the(long long)ncast (left conjunct) was evaluated before the magnitude guard. For any|n| >= 2^63reaching this path that is undefined behavior (float-cast-overflow — flagged by UBSan/CodeQL). Swapping the conjuncts makes the range check short-circuit and guard the cast:if (fabs(n) < 9007199254740992.0 && n == (long long)n)In-range formatting is unchanged (an out-of-range value falls to the
%.*gbranch either way, so local output is identical — the UB only manifests under UBSan/CodeQL, which is CIs regression guard here)../build.shclean;run_all_tests.sh3183/3183.Generated by Claude Fable 5 (brief, review), Claude Opus 4.8 (implementation)