Thread

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

Peter Eisentraut <peter@eisentraut.org> — 2025-12-18T07:43:34Z

On 18.12.25 01:22, Chao Li wrote:
>> 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?
> 
> Did you mean to say “duplicate” instead of “explicit”?

No, I meant explicit.  I didn't find an example in the thread you linked 
to, but I suppose you are writing something like

enum foo {
   bar = 1,
   baz = 2,
};

But why make those assignments at all.  You could just write

enum foo {
   bar,
   baz,
};