Re: BUG #14431: ERROR: XX000: relation 5022917 has no triggers ("should not happen")

On 11/24/2016 12:49 PM, benjie(at)jemjie(dot)com wrote:
> The following bug has been logged on the website:
>
> Bug reference: 14431
> Logged by: Benjie Gillam
> Email address: benjie(at)jemjie(dot)com
> PostgreSQL version: 9.5.2
> Operating system: OS X 10.11.5
> Description:
>
> I've triggered an error that "should not happen", took me a while to figure
> out what I'd done.
>
> I've managed to build a small test case that reproduces the issue (it
> relates to `deferrable initially deferred`):
>
> https://gist.github.com/benjie/9d4f8df41ebf7a0fb78788c00c75561a

For the archives, the test case at that link is:

<>
begin;
create table a(foo varchar not null primary key);
create table b(foo varchar not null primary key, constraint qux
foreign key (foo) references a deferrable initially deferred);
create function bar() returns trigger as $$
begin
if TG_OP = 'INSERT' then
insert into b(foo) values(new.foo);
elsif TG_OP = 'DELETE' then
delete from b where foo = old.foo;
end if;
return new;
end;
$$ language plpgsql;

create trigger bar after insert or delete on a for each row execute
procedure bar();
commit;

insert into a values('baz');

begin;
delete from a where foo = 'baz';
drop trigger bar on a;
drop function bar();
alter table b drop constraint qux;
commit;
</>

I can reproduce it.

> I don't think it's a particularly important issue. Here's the relevant line
> of code:
>
> https://github.com/postgres/postgres/blob/6fa391be4e83139cd134d5ccfc1499809bb8c98c/src/backend/commands/trigger.c#L4027-L4029

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