Fuzzer failure in math_expression_fuzz_run_mvcc with trigonometry functions

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Description

[78](https://github.com/tursodatabase/turso/actions/runs/21879378973/job/63157240521?pr=4999#step:11:179)

    thread 'fuzz_tests::math_expression_fuzz_run_mvcc' panicked at tests/fuzz/mod.rs:4337:21:
    query: SELECT (trunc(atanh((tanh(0.0 - 2.0) + mod(2.0, 2.0) * (-2.0 - 0.0))))) + -2.0, limbo: -3.0, sqlite: -4.0 seed: 1770752065271

Contributor guide

Research direction

Reproduce the failing fuzz test locally by running the specific seed (1770752065271) and trace the execution of the math expression through the SQL parser, validator, and executor. Compare the result with SQLite's result to identify where the discrepancy occurs. Focus on the implementation of `atanh`, `tanh`, `trunc`, and `mod` functions.

Tech stack

rust

Domain

database

Issue type

Bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

Half day

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

Active

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

Clear

Prerequisites

Rustfuzzing

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

40