Re: Add sanity check for duplicate enum values in GUC definitions

Chao Li <li.evan.chao@gmail.com>

From: Chao Li <li.evan.chao@gmail.com>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: Postgres hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-12-18T00:22:13Z
Lists: pgsql-hackers

> On Dec 17, 2025, at 22:51, Peter Eisentraut <peter@eisentraut.org> wrote:
> 
> On 15.12.25 10:16, Chao Li wrote:
>> The motivation for this patch comes from my own experience. While working on [1]. I added an enum-typed GUC and made a copy-and-paste mistake, assigning the same numeric value to two different enum entries. This resulted in confusing runtime behavior and cost me about an hour to track down.
> 
> Why do you assign explicit values at all?

Hi Peter,

Did you mean to say “duplicate” instead of “explicit”?

Duplicate values assigning to different enum items was a copy-paste mistake I made during development, which wasted my time on debugging the issue. So I wanted to add this sanity check to quickly report such mistake in the first place.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/