BUG #16557: getProcedureColumns() function returns columns, when there is no existing Stored Procedure in the DB

The following bug has been logged on the website:

Bug reference: 16557
Logged by: Adarshdeep Cheema
Email address: adarshdeep(dot)cheema(at)ibm(dot)com
PostgreSQL version: 12.2
Operating system: Windows
Description:

Create any user defined function using Postgres 12.3 Server, we are using
postgresql-42.2.11 JDBC driver

DDLs:
CREATE FUNCTION findec(pdec numeric) RETURNS numeric
LANGUAGE plpgsql
AS $$
declare r decimal(7,2);
begin
r = PDEC;
return r;
end;
$$;

a) When we use the following Java code, then we get nothing as we do no have
any Stored Procedure defined, which is expected
resultSet= metadata.getProcedures(null , "public", null); ,
while (resultSet.next()){

System.out.print(resultSet.getString(1)+" ");
System.out.print(resultSet.getString(2)+" ");
System.out.print(resultSet.getString(3)+" ");
System.out.print(resultSet.getString(4)+" ");
System.out.print(resultSet.getString(5)+" ");
System.out.println(resultSet.getString(6)+" ");
}

b) Now change the JAVA code to the following and you will get two columns in
the resultSet, which is a bug as there is no StoredProcedure Defined in the
database

resultSet= metadata.getProcedureColumns(null , "public", "findec", null);
,
while (resultSet.next()){

System.out.print(resultSet.getString(1)+" ");
System.out.print(resultSet.getString(2)+" ");
System.out.print(resultSet.getString(3)+" ");
System.out.print(resultSet.getString(4)+" ");
System.out.print(resultSet.getString(5)+" ");
System.out.println(resultSet.getString(6)+" ");
}

OUTPUT:
null public findec returnValue 5 2
null public findec pdec 1 2