reserved_role crashes causes segfault when renaming tables

[Brad Nicholson]

Bug report

Describe the bug

If you enable supautils.reserved_roles, any attempts to rename a table via ALTER TABLE crash the database.

To Reproduce

• Configure Postgres with supautils and set supautils.reserved_roles to a reserved role.
• Create a table
• Attempt to rename the table with alter table - postgres will crash.

For example:

Settings from postgresql.conf

# Add settings for extensions here
shared_preload_libraries = 'supautils'
supautils.reserved_memberships = 'pg_read_server_files,pg_write_server_files,pg_execute_server_program,pg_read_all_settings'
supautils.reserved_roles = 'user_a'

Users:

test=> \du
                                   List of roles
 Role name |                         Attributes                         | Member of
-----------+------------------------------------------------------------+-----------
 admin     | Create role, Create DB                                     | {}
 postgres  | Superuser, Create role, Create DB, Replication, Bypass RLS | {}
 user_a    |                                                            | {}

Create a table and rename it:

[root@c2e4ce2e2625 supautils-1.1.0]# psql -U admin test
psql (12.7)
Type "help" for help.

test=> CREATE TABLE foo (id int);
CREATE TABLE
test=> ALTER TABLE foo RENAME TO bar;
server closed the connection unexpectedly
	This probably means the server terminated abnormally
	before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!>

Debug PG logs from the above:

2021-08-31 18:26:06.667 UTC [226] DEBUG:  CommitTransaction(1) name: unnamed; blockState: STARTED; state: INPROGRESS, xid/subid/cid: 0/1/0
2021-08-31 18:26:08.901 UTC [226] DEBUG:  StartTransaction(1) name: unnamed; blockState: DEFAULT; state: INPROGRESS, xid/subid/cid: 0/1/0
2021-08-31 18:26:08.909 UTC [183] LOG:  server process (PID 226) was terminated by signal 11: Segmentation fault
2021-08-31 18:26:08.909 UTC [183] DETAIL:  Failed process was running: ALTER TABLE foo RENAME TO bar;
2021-08-31 18:26:08.909 UTC [183] LOG:  terminating any other active server processes
2021-08-31 18:26:08.910 UTC [220] WARNING:  terminating connection because of crash of another server process
2021-08-31 18:26:08.910 UTC [220] DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.

If I remove supautils.reserved_roles from the config, the rename statement works.

Expected behavior

Renaming a table should not cause a segfault.

System information

• OS: UBI 8
• Version of supabase: 1.1.0
• Version of Postgres 12.7 (hits other versions though)