Re: domains code query

Andrew Dunstan <andrew@dunslane.net> writes:
> domains.c contains the followng snippet in domain_in():

>     else* *if* (my_extra->domain_type != domainType)
>         domain_state_setup(my_extra, domainType, false,
>                            fcinfo->flinfo->fn_mcxt);

> We were just looking at this code (in the context of implementing enums) and wondered when this case might arise. 
> Would it be when more than one domain is used in a table row? Or are we smarter than that?

I think it's just defensive programming.  The logic was copied from
array_in which does something similar, but AFAIR there's not really
any code path which would feed differing input types to the same
function call within a single query execution.  Still, since it takes
only an extra comparison or so to handle the scenario, why not?
        regards, tom lane