Handle dependencies properly in ALTER POLICY

ALTER POLICY hadn't fully considered partial policy alternation
(eg: change just the roles on the policy, or just change one of
the expressions) when rebuilding the dependencies.  Instead, it
would happily remove all dependencies which existed for the
policy and then only recreate the dependencies for the objects
referred to in the specific ALTER POLICY command.

Correct that by extracting and building the dependencies for all
objects referenced by the policy, regardless of if they were
provided as part of the ALTER POLICY command or were already in
place as part of the pre-existing policy.

1 files changed, 97 insertions, 0 deletions

diff --git a/src/backend/commands/policy.c b/src/backend/commands/policy.c
index 6399b2e3eb7..09164c6ed36 100644
--- a/src/backend/commands/policy.c
+++ b/src/backend/commands/policy.c
@@ -766,6 +766,35 @@ AlterPolicy(AlterPolicyStmt *stmt)
 		replaces[Anum_pg_policy_polroles - 1] = true;
 		values[Anum_pg_policy_polroles - 1] = PointerGetDatum(role_ids);
 	}
+	else
+	{
+		Oid        *roles;
+		Datum		roles_datum;
+		bool		attr_isnull;
+		ArrayType  *policy_roles;
+
+		/*
+		 * We need to pull the set of roles this policy applies to from
+		 * what's in the catalog, so that we can recreate the dependencies
+		 * correctly for the policy.
+		 */
+
+		roles_datum = heap_getattr(policy_tuple, Anum_pg_policy_polroles,
+								   RelationGetDescr(pg_policy_rel),
+								   &attr_isnull);
+		Assert(!attr_isnull);
+
+		policy_roles = DatumGetArrayTypePCopy(roles_datum);
+
+		roles = (Oid *) ARR_DATA_PTR(policy_roles);
+
+		nitems = ARR_DIMS(policy_roles)[0];
+
+		role_oids = (Datum *) palloc(nitems * sizeof(Datum));
+
+		for (i = 0; i < nitems; i++)
+			role_oids[i] = ObjectIdGetDatum(roles[i]);
+	}
 
 	if (qual != NULL)
 	{
@@ -773,6 +802,40 @@ AlterPolicy(AlterPolicyStmt *stmt)
 		values[Anum_pg_policy_polqual - 1]
 			= CStringGetTextDatum(nodeToString(qual));
 	}
+	else
+	{
+		Datum	value_datum;
+		bool	attr_isnull;
+
+		/*
+		 * We need to pull the USING expression and build the range table for
+		 * the policy from what's in the catalog, so that we can recreate
+		 * the dependencies correctly for the policy.
+		 */
+
+		/* Check if the policy has a USING expr */
+		value_datum = heap_getattr(policy_tuple, Anum_pg_policy_polqual,
+								   RelationGetDescr(pg_policy_rel),
+								   &attr_isnull);
+		if (!attr_isnull)
+		{
+			char	   *qual_value;
+			ParseState *qual_pstate = make_parsestate(NULL);
+
+			/* parsestate is built just to build the range table */
+			qual_pstate = make_parsestate(NULL);
+
+			qual_value = TextDatumGetCString(value_datum);
+			qual = stringToNode(qual_value);
+
+			/* Add this rel to the parsestate's rangetable, for dependencies */
+			addRangeTableEntryForRelation(qual_pstate, target_table, NULL,
+										  false, false);
+
+			qual_parse_rtable = qual_pstate->p_rtable;
+			free_parsestate(qual_pstate);
+		}
+	}
 
 	if (with_check_qual != NULL)
 	{
@@ -780,6 +843,40 @@ AlterPolicy(AlterPolicyStmt *stmt)
 		values[Anum_pg_policy_polwithcheck - 1]
 			= CStringGetTextDatum(nodeToString(with_check_qual));
 	}
+	else
+	{
+		Datum	value_datum;
+		bool	attr_isnull;
+
+		/*
+		 * We need to pull the WITH CHECK expression and build the range table
+		 * for the policy from what's in the catalog, so that we can recreate
+		 * the dependencies correctly for the policy.
+		 */
+
+		/* Check if the policy has a WITH CHECK expr */
+		value_datum = heap_getattr(policy_tuple, Anum_pg_policy_polwithcheck,
+								   RelationGetDescr(pg_policy_rel),
+								   &attr_isnull);
+		if (!attr_isnull)
+		{
+			char	   *with_check_value;
+			ParseState *with_check_pstate = make_parsestate(NULL);
+
+			/* parsestate is built just to build the range table */
+			with_check_pstate = make_parsestate(NULL);
+
+			with_check_value = TextDatumGetCString(value_datum);
+			with_check_qual = stringToNode(with_check_value);
+
+			/* Add this rel to the parsestate's rangetable, for dependencies */
+			addRangeTableEntryForRelation(with_check_pstate, target_table, NULL,
+										  false, false);
+
+			with_check_parse_rtable = with_check_pstate->p_rtable;
+			free_parsestate(with_check_pstate);
+		}
+	}
 
 	new_tuple = heap_modify_tuple(policy_tuple,
 								  RelationGetDescr(pg_policy_rel),