Subject: UBSan failing on expensive test(s)

From: Junio C Hamano <[email-masked]>
Date: Sat, 16 May 2026 08:43:07 +0900

This started happening on 'next' that runs EXPENSIVE tests thanks to
Dscho's recent updates to enable them in CI.

https://github.com/git/git/actions/runs/25896439353/job/76110441841#step:10:2172

It claims that """

    commit.c:1574:6: runtime error: signed integer overflow:
    -2147483648 - 1 cannot be represented in type 'int'

""".

Another is related in the sense that it used to be hidden behind
EXPENSIVE prerequisite, but is probably unrelated.

https://github.com/git/git/actions/runs/25896439353/job/76110441842#step:10:156