Re: tablecmds.c/MergeAttributes() cleanup

On 2023-Aug-29, Peter Eisentraut wrote:


Regarding this hunk in 0002,

> @@ -3278,13 +3261,16 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
>   *
>   * constraints is a list of CookedConstraint structs for previous constraints.
>   *
> - * Returns true if merged (constraint is a duplicate), or false if it's
> - * got a so-far-unique name, or throws error if conflict.
> + * If the constraint is a duplicate, then the existing constraint's
> + * inheritance count is updated.  If the constraint doesn't match or conflict
> + * with an existing one, a new constraint is appended to the list.  If there
> + * is a conflict (same name but different expression), throw an error.

This wording confused me:

"If the constraint doesn't match or conflict with an existing one, a new
constraint is appended to the list."

I first read it as "doesn't match or conflicts with ..." (i.e., the
negation only applied to the first verb, not both) which would have been
surprising (== broken) behavior.

I think it's clearer if you say "doesn't match nor conflict", but I'm
not sure if this is grammatically correct.

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/