po 9. 8. 2021 v 23:13 odesílatel Tom Lane <tgl@xxxxxxxxxxxxx> napsal:
Pavel Stehule <pavel.stehule@xxxxxxxxx> writes:
> Some errors like this, but not this can be detected by plpgsql_check
> https://github.com/okbob/plpgsql_check - probably the heuristic for type
> check is not complete.
STRICTMULTIASSIGNMENT would detect most cases of this, except that
the condition is checked too late. We'd need to count the fields
*before* trying to assign values, not after.
I use some fragments of this routine. But the problem was so I did implicit unnesting, although plpgsql doesn't do this
postgres=# create or replace function broken_into()
returns void as $$
declare v typ2;
begin
-- should to fail
select (10,20)::typ2 into v;
-- should be ok
select ((10,20)::typ2).* into v;
-- should to fail
execute 'select (10,20)::typ2' into v;
-- should be ok
execute 'select ((10,20)::typ2).*' into v;
end;
$$ language plpgsql;
CREATE FUNCTION
postgres=# select * from plpgsql_check_function('broken_into', fatal_errors => false);
┌────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ plpgsql_check_function │
╞════════════════════════════════════════════════════════════════════════════════════════════════════════════╡
│ error:42804:5:SQL statement:cannot cast composite value of "typ2" type to a scalar value of "integer" type │
│ warning:00000:5:SQL statement:too few attributes for composite variable │
│ error:42804:9:EXECUTE:cannot cast composite value of "typ2" type to a scalar value of "integer" type │
│ warning:00000:9:EXECUTE:too few attributes for composite variable │
│ warning extra:00000:2:DECLARE:never read variable "v" │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
(5 rows)
returns void as $$
declare v typ2;
begin
-- should to fail
select (10,20)::typ2 into v;
-- should be ok
select ((10,20)::typ2).* into v;
-- should to fail
execute 'select (10,20)::typ2' into v;
-- should be ok
execute 'select ((10,20)::typ2).*' into v;
end;
$$ language plpgsql;
CREATE FUNCTION
postgres=# select * from plpgsql_check_function('broken_into', fatal_errors => false);
┌────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ plpgsql_check_function │
╞════════════════════════════════════════════════════════════════════════════════════════════════════════════╡
│ error:42804:5:SQL statement:cannot cast composite value of "typ2" type to a scalar value of "integer" type │
│ warning:00000:5:SQL statement:too few attributes for composite variable │
│ error:42804:9:EXECUTE:cannot cast composite value of "typ2" type to a scalar value of "integer" type │
│ warning:00000:9:EXECUTE:too few attributes for composite variable │
│ warning extra:00000:2:DECLARE:never read variable "v" │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
(5 rows)
Regards
Pavel
In the meantime, it does seem like the docs could be more explicit
about this, and perhaps give an example showing the (x).* solution.
regards, tom lane
