Horton

Re: BUG #18240: Undefined behaviour in cash_mul_flt8() and friends

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Michael Paquier <michael@paquier.xyz>
Cc: exclusion@gmail.com, pgsql-bugs@lists.postgresql.org
Date: 2023-12-11T15:05:53Z
Lists: pgsql-bugs 
Michael Paquier <michael@paquier.xyz> writes:
> On Mon, Dec 11, 2023 at 06:00:02AM +0000, PG Bug reporting form wrote:
>> The following multiplication:
>> SELECT 1_000_000_000::money * 1_000_000_000::float8;
>> gives the incorrect result:
>> -$92,233,720,368,547,758.08

> Yep, good catch.  Reproduced here.

Yeah, approximately none of cash.c pays any attention to the risks
of overflow/underflow.  Improving that situation would be a good
finger exercise for some aspiring hacker, perhaps.  Although I bet
somebody will ask again why it is that we continue to support the
money type.

			regards, tom lane

Commits

  1. Add overflow checks to money type.

  2. Reduce dependency to money data type in main regression test suite