BUG #19682: Unable to drop a user with default privileges revoked

The following bug has been logged on the website:

Bug reference: 19682
Logged by: Sylvain Perraud
Email address: ext(dot)solutec(dot)sperraud(at)grandlyon(dot)com
PostgreSQL version: 18.4
Operating system: RHEL 9.8
Description:

Hello,

Scenario 1 : create a user alpha then grant default privileges to himself

test=# create user alpha;
CREATE ROLE
test=# \ddp alpha
Default access privileges
Owner | Schema | Type | Access privileges
-------+--------+------+-------------------
(0 rows)

test=# ALTER DEFAULT PRIVILEGES FOR ROLE alpha GRANT ALL ON TABLES to
alpha;
ALTER DEFAULT PRIVILEGES
test=# \ddp alpha
Default access privileges
Owner | Schema | Type | Access privileges
-------+--------+------+-------------------
(0 rows)

test=# drop user alpha;
DROP ROLE

Conclusion 1 : Drop is working

***********************************************************************************************************************************************************************************
Scenario 2 : create a user alpha then revoke default privileges from himself
test=# create user alpha;
CREATE ROLE
test=# ALTER DEFAULT PRIVILEGES FOR ROLE alpha REVOKE ALL ON TABLES FROM
alpha;
ALTER DEFAULT PRIVILEGES
test=# \ddp alpha
Default access privileges
Owner | Schema | Type | Access privileges
-------+--------+-------+-------------------
alpha | | table | (none)
(1 row)

test=# drop user alpha;
ERROR: role "alpha" cannot be dropped because some objects depend on it
DETAIL: owner of default privileges on new relations belonging to role
alpha

Conclusion 2 : Drop is not working
***********************************************************************************************************************************************************************************
Scenario 3 : create a user alpha and beta then grant default privileges to
both users
test=# create user alpha;
CREATE ROLE
test=# create user beta;
CREATE ROLE
test=# ALTER DEFAULT PRIVILEGES FOR ROLE alpha GRANT ALL ON TABLES to beta;
ALTER DEFAULT PRIVILEGES
test=# \ddp alpha
Default access privileges
Owner | Schema | Type | Access privileges
-------+--------+-------+---------------------
alpha | | table | beta=arwdDxtm/alpha
(1 row)

test=# ALTER DEFAULT PRIVILEGES FOR ROLE alpha GRANT ALL ON TABLES to
alpha;
ALTER DEFAULT PRIVILEGES
test=# \ddp alpha
Default access privileges
Owner | Schema | Type | Access privileges
-------+--------+-------+----------------------
alpha | | table | alpha=arwdDxtm/alpha+
| | | beta=arwdDxtm/alpha
(1 row)

test=# drop user alpha;
ERROR: role "alpha" cannot be dropped because some objects depend on it
DETAIL: owner of default privileges on new relations belonging to role
alpha

test=# ALTER DEFAULT PRIVILEGES FOR ROLE alpha REVOKE ALL ON TABLES FROM
beta;
ALTER DEFAULT PRIVILEGES
test=# \ddp alpha
Default access privileges
Owner | Schema | Type | Access privileges
-------+--------+------+-------------------
(0 rows)

test=# drop user alpha;
DROP ROLE

Conclusion 3 : Drop is working whereas DEFAULT PRIVILEGES are still granted
to alpha