[YSQL] Dropping constraint on parent table of inheritance fails

[iSignal]

Jira Link: DB-15562

Description

A foreign key constraint that exists only on the parent

CREATE TABLE test_primary_constraints(id int PRIMARY KEY);
CREATE TABLE test_foreign_constraints(id1 int REFERENCES test_primary_constraints(id));
CREATE TABLE test_foreign_constraints_inh () INHERITS (test_foreign_constraints);

ALTER TABLE test_foreign_constraints DROP CONSTRAINT test_foreign_constraints_id1_fkey;

The issue also occurs with primary key constraints that exist only on the parent

create table par(id int primary key, c1 int);
create table child(ch1 int) inherits (par);
alter table par drop constraint par_pkey;
ERROR:  constraint "par_pkey" for table "child" does not exist

As a workaround, use alter table only for both these cases to drop the primary key / foreign key from just the parent.

yugabyte=# ALTER TABLE ONLY test_foreign_constraints DROP CONSTRAINT test_foreign_constraints_id1_fkey;
ALTER TABLE

yugabyte=# alter table only par drop constraint par_pkey;
NOTICE:  table rewrite may lead to inconsistencies
DETAIL:  Concurrent DMLs may not be reflected in the new table.
HINT:  See https://github.com/yugabyte/yugabyte-db/issues/19860. Set 'ysql_suppress_unsafe_alter_notice' yb-tserver gflag to true to suppress this notice.
ALTER TABLE

Issue Type

kind/bug

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