Re: BUG #19586: money division overflow

Hi, Michael!

Thanks for the report.
Patch attached.

---
Regards,
Rachitskiy Andrey

ср, 29 июл. 2026 г. в 22:54, PG Bug reporting form <noreply(at)postgresql(dot)org>:

> The following bug has been logged on the website:
>
> Bug reference: 19586
> Logged by: Michael Malis
> Email address: malis(at)pgrust(dot)com
> PostgreSQL version: 18.4
> Operating system: Linux x86_64 and Linux aarch64
> Description:
>
> cash_div_int64() in src/backend/utils/adt/cash.c guards against division by
> zero but not against the INT64_MIN / -1 overflow:
>
> cash_div_int64(Cash c, int64 i)
> {
> if (unlikely(i == 0))
> ereport(ERROR, (errcode(ERRCODE_DIVISION_BY_ZERO), ...));
> return c / i;
> }
>
> Commit 4f96281587 ("Add overflow checks to money type", 2024-07-19, fixing
> bug
> #18240) added pg_mul_s64_overflow() checks to cash_mul_int64() and the
> float paths, but the division path was not covered.
>
> Steps to reproduce
>
> SELECT '-92233720368547758.08'::money / -1;
>
> Actual results
>
> On x86-64, the hardware division trap is caught by PostgreSQL's SIGFPE
> handler and surfaces as a misleading error class for an integer overflow:
>
> ERROR: floating-point exception
> DETAIL: An invalid floating-point operation was signaled...
> On aarch64, where the division does not trap, the wrong value is returned
> silently, with no error:
>
> -$92,233,720,368,547,758.08
> i.e. a negative value divided by -1 remains negative.
>
> Expected results
>
> The same treatment int8div() already gives the identical arithmetic, on
> every platform:
>
> SELECT (-9223372036854775808)::bigint / -1;
> ERROR: bigint out of range
>
> Multiplication in the money type is already guarded and behaves correctly:
>
> SELECT '-92233720368547758.08'::money * -1;
> ERROR: money out of range
>
> I would be happy to provide a patch.
>
>
>
>
>