Revert "Avoid race condition between "GRANT role" and "DROP ROLE"".

This reverts commit 98fc31d6499163a0a781aa6f13582a07f09cd7c6.
That change allowed DROP OWNED BY to drop grants of the target
role to other roles, arguing that nobody would need those
privileges anymore.  But that's not so: if you're not superuser,
you still need admin privilege on the target role so you can
drop it.

It's not clear whether or how the dependency-based approach
to solving the original problem can be adapted to keep these
grants.  Since v18 release is fast approaching, the sanest
thing to do seems to be to revert this patch for now.  The
race-condition problem is low severity and not worth taking
risks for.

I didn't force a catversion bump in 98fc31d64, so I won't do
so here either.

Reported-by: Dipesh Dhameliya <dipeshdhameliya125@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CABgZEgczOFicCJoqtrH9gbYMe_BV3Hq8zzCBRcMgmU6LRsihUA@mail.gmail.com
Backpatch-through: 18

doc/src/sgml/ref/drop_owned.sgml

@@ -33,7 +33,7 @@ DROP OWNED BY { <replaceable class="parameter">name</replaceable> | CURRENT_ROLE
    database that are owned by one of the specified roles. Any
    privileges granted to the given roles on objects in the current
    database or on shared objects (databases, tablespaces, configuration
-   parameters, or other roles) will also be revoked.
+   parameters) will also be revoked.
   </para>
  </refsect1>
 

src/backend/commands/user.c

@@ -30,7 +30,6 @@
 #include "commands/defrem.h"
 #include "commands/seclabel.h"
 #include "commands/user.h"
-#include "lib/qunique.h"
 #include "libpq/crypt.h"
 #include "miscadmin.h"
 #include "storage/lmgr.h"
@@ -490,7 +489,8 @@ CreateRole(ParseState *pstate, CreateRoleStmt *stmt)
 	 * Advance command counter so we can see new record; else tests in
 	 * AddRoleMems may fail.
 	 */
-	CommandCounterIncrement();
+	if (addroleto || adminmembers || rolemembers)
+		CommandCounterIncrement();
 
 	/* Default grant. */
 	InitGrantRoleOptions(&popt);
@@ -1904,8 +1904,7 @@ AddRoleMems(Oid currentUserId, const char *rolename, Oid roleid,
 		else
 		{
 			Oid			objectId;
-			Oid		   *newmembers = (Oid *) palloc(3 * sizeof(Oid));
-			int			nnewmembers;
+			Oid		   *newmembers = palloc(sizeof(Oid));
 
 			/*
 			 * The values for these options can be taken directly from 'popt'.
@@ -1947,22 +1946,12 @@ AddRoleMems(Oid currentUserId, const char *rolename, Oid roleid,
 									new_record, new_record_nulls);
 			CatalogTupleInsert(pg_authmem_rel, tuple);
 
-			/*
-			 * Record dependencies on the roleid, member, and grantor, as if a
-			 * pg_auth_members entry were an object ACL.
-			 * updateAclDependencies() requires an input array that is
-			 * palloc'd (it will free it), sorted, and de-duped.
-			 */
-			newmembers[0] = roleid;
-			newmembers[1] = memberid;
-			newmembers[2] = grantorId;
-			qsort(newmembers, 3, sizeof(Oid), oid_cmp);
-			nnewmembers = qunique(newmembers, 3, sizeof(Oid), oid_cmp);
-
+			/* updateAclDependencies wants to pfree array inputs */
+			newmembers[0] = grantorId;
 			updateAclDependencies(AuthMemRelationId, objectId,
 								  0, InvalidOid,
 								  0, NULL,
-								  nnewmembers, newmembers);
+								  1, newmembers);
 		}
 
 		/* CCI after each change, in case there are duplicates in list */

src/test/regress/expected/privileges.out

@@ -113,36 +113,6 @@ CREATE USER regress_priv_user2;
 CREATE USER regress_priv_user3;
 CREATE USER regress_priv_user4;
 CREATE USER regress_priv_user5;
--- DROP OWNED should also act on granted and granted-to roles
-GRANT regress_priv_user1 TO regress_priv_user2;
-GRANT regress_priv_user2 TO regress_priv_user3;
-SELECT roleid::regrole, member::regrole FROM pg_auth_members
-  WHERE roleid IN ('regress_priv_user1'::regrole,'regress_priv_user2'::regrole)
-  ORDER BY roleid::regrole::text;
-       roleid       |       member       
---------------------+--------------------
- regress_priv_user1 | regress_priv_user2
- regress_priv_user2 | regress_priv_user3
-(2 rows)
-
-REASSIGN OWNED BY regress_priv_user2 TO regress_priv_user4;  -- no effect
-SELECT roleid::regrole, member::regrole FROM pg_auth_members
-  WHERE roleid IN ('regress_priv_user1'::regrole,'regress_priv_user2'::regrole)
-  ORDER BY roleid::regrole::text;
-       roleid       |       member       
---------------------+--------------------
- regress_priv_user1 | regress_priv_user2
- regress_priv_user2 | regress_priv_user3
-(2 rows)
-
-DROP OWNED BY regress_priv_user2;  -- removes both grants
-SELECT roleid::regrole, member::regrole FROM pg_auth_members
-  WHERE roleid IN ('regress_priv_user1'::regrole,'regress_priv_user2'::regrole)
-  ORDER BY roleid::regrole::text;
- roleid | member 
---------+--------
-(0 rows)
-
 GRANT pg_read_all_data TO regress_priv_user6;
 GRANT pg_write_all_data TO regress_priv_user7;
 GRANT pg_read_all_settings TO regress_priv_user8 WITH ADMIN OPTION;

src/test/regress/sql/privileges.sql

@@ -90,21 +90,6 @@ CREATE USER regress_priv_user3;
 CREATE USER regress_priv_user4;
 CREATE USER regress_priv_user5;
 
--- DROP OWNED should also act on granted and granted-to roles
-GRANT regress_priv_user1 TO regress_priv_user2;
-GRANT regress_priv_user2 TO regress_priv_user3;
-SELECT roleid::regrole, member::regrole FROM pg_auth_members
-  WHERE roleid IN ('regress_priv_user1'::regrole,'regress_priv_user2'::regrole)
-  ORDER BY roleid::regrole::text;
-REASSIGN OWNED BY regress_priv_user2 TO regress_priv_user4;  -- no effect
-SELECT roleid::regrole, member::regrole FROM pg_auth_members
-  WHERE roleid IN ('regress_priv_user1'::regrole,'regress_priv_user2'::regrole)
-  ORDER BY roleid::regrole::text;
-DROP OWNED BY regress_priv_user2;  -- removes both grants
-SELECT roleid::regrole, member::regrole FROM pg_auth_members
-  WHERE roleid IN ('regress_priv_user1'::regrole,'regress_priv_user2'::regrole)
-  ORDER BY roleid::regrole::text;
-
 GRANT pg_read_all_data TO regress_priv_user6;
 GRANT pg_write_all_data TO regress_priv_user7;
 GRANT pg_read_all_settings TO regress_priv_user8 WITH ADMIN OPTION;