Publication of same parent table with ONLY-ness mismatch should error

Hi.

While reviewing another thread, I had cause to enumerate and try many
dozens of CREATE PUBLICATION clause combinations. I found one
combination that gave an unexpected result. IMO this a bug:

CREATE PUBLICATION ... FOR TABLE s1.parent, TABLE ONLY s1.parent;
-- No error? First wins. Behaves like FOR TABLE

CREATE PUBLICATION ... FOR TABLE ONLY s1.parent, TABLE s1.parent;
-- No error? First wins. Behaves like FOR TABLE ONLY

Below is how to reproduce:

======

CREATE SCHEMA s1;
CREATE SCHEMA s2;

-- Create the parent table
CREATE TABLE IF NOT EXISTS s1.parent ( id SERIAL PRIMARY KEY, name
TEXT NOT NULL, email TEXT );

-- Create the child tables that inherit from parent
CREATE TABLE IF NOT EXISTS s1.child1 ( department TEXT NOT NULL )
INHERITS (s1.parent);
CREATE TABLE IF NOT EXISTS s2.child2 ( department TEXT NOT NULL )
INHERITS (s1.parent);

CREATE PUBLICATION pub_table FOR TABLE s1.parent;
CREATE PUBLICATION pub_tableonly FOR TABLE ONLY s1.parent;

CREATE PUBLICATION pub_table_tableonly FOR TABLE s1.parent, TABLE ONLY
s1.parent;
CREATE PUBLICATION pub_tableonly_table FOR TABLE ONLY s1.parent, TABLE
s1.parent;

CREATE PUBLICATION pub_s1 FOR TABLES IN SCHEMA s1;
CREATE PUBLICATION pub_s1_table FOR TABLES IN SCHEMA s1, TABLE s1.parent;
CREATE PUBLICATION pub_s1_tableonly FOR TABLES IN SCHEMA s1, TABLE
ONLY s1.parent;
CREATE PUBLICATION pub_table_s1 FOR TABLE s1.parent, TABLES IN SCHEMA s1;
CREATE PUBLICATION pub_tableonly_s1 FOR TABLE ONLY s1.parent, TABLES
IN SCHEMA s1;

SELECT pubname, schemaname, tablename FROM pg_publication_tables ORDER
by pubname;

~~~

Results (unpatched):

pubname schemaname tablename

-- FOR TABLES IN SCHEMA does not reach across to s2. ok
pub_s1 s1 parent
pub_s1 s1 child1

-- Extra FOR TABLE does reach across to schema s2. good!
pub_s1_table s1 parent
pub_s1_table s1 child1
pub_s1_table s2 child2

-- Extra FOR TABLE ONLY does not reach into s2. ok
pub_s1_tableonly s1 parent
pub_s1_tableonly s1 child1

-- FOR TABLE reaches into s2. ok
pub_table s1 parent
pub_table s1 child1
pub_table s2 child2

-- Extra FOR TABLE does reach across into schema s2. good!
pub_table_s1 s1 parent
pub_table_s1 s1 child1
pub_table_s1 s2 child2

-- FOR TABLE ONLY is just that table. ok
pub_tableonly s1 parent

-- Extra FOR TABLE ONLY does not reach into s2. ok
pub_tableonly_s1 s1 parent
pub_tableonly_s1 s1 child1

-- No error? First wins. Behaves like FOR TABLE ONLY. BUG??
pub_tableonly_table s1 parent

-- No error? First wins. Behaves like FOR TABLE. BUG??
pub_table_tableonly s1 parent
pub_table_tableonly s1 child1
pub_table_tableonly s2 child2

======

The "FOR TABLE s1.parent" and "FOR TABLE ONLY s1.parent" are clearly
not the same thing, so why are they allowed to co-exist in the same
publication. AFAIK, nothing else uses a "first-one-wins" behaviour
like this (e.g. repeated tables with different column-lists gives an
error, not first-one-wins).

IMO this is a bug.

My AI query agrees that this "first-one-wins" rule for TABLE ONLY is
undocumented and has not been discussed before -- it's just some
undocumented/untested side-effect of a 2017 code that does "continue;"
whenever the same relid is encountered in the publication.

~~~

PSA a patch to now report an ONLY-ness mismatch as another
"conflicting" error. Note, there were already other similar conflict
errors for clashing column-lists and clashing row filters, but the
clashing ONLY-ness error was missing.

New regression tests added.

`make check-world` is unaffected, and passes OK.

======
Kind Regards,
Peter Smith.
Fujitsu Australia