Add assign_expr_collations() to CreatePolicy() and AlterPolicy().

As noted by Noah Misch, CreatePolicy() and AlterPolicy() omit to call
assign_expr_collations() on the node trees. Fix the omission and add
his test case to the rowsecurity regression test.

src/backend/commands/policy.c

@@ -538,6 +538,10 @@ CreatePolicy(CreatePolicyStmt *stmt)
 										   EXPR_KIND_WHERE,
 										   "POLICY");
 
+	/* Fix up collation information */
+	assign_expr_collations(qual_pstate, qual);
+	assign_expr_collations(with_check_pstate, with_check_qual);
+
 	/* Open pg_policy catalog */
 	pg_policy_rel = heap_open(PolicyRelationId, RowExclusiveLock);
 
@@ -681,6 +685,9 @@ AlterPolicy(AlterPolicyStmt *stmt)
 									EXPR_KIND_WHERE,
 									"POLICY");
 
+		/* Fix up collation information */
+		assign_expr_collations(qual_pstate, qual);
+
 		qual_parse_rtable = qual_pstate->p_rtable;
 		free_parsestate(qual_pstate);
 	}
@@ -701,6 +708,9 @@ AlterPolicy(AlterPolicyStmt *stmt)
 											   EXPR_KIND_WHERE,
 											   "POLICY");
 
+		/* Fix up collation information */
+		assign_expr_collations(with_check_pstate, with_check_qual);
+
 		with_check_parse_rtable = with_check_pstate->p_rtable;
 		free_parsestate(with_check_pstate);
 	}

src/test/regress/expected/rowsecurity.out

@@ -2730,6 +2730,27 @@ ERROR:  permission denied for relation copy_t
 RESET SESSION AUTHORIZATION;
 DROP TABLE copy_t;
 --
+-- Collation support
+--
+BEGIN;
+SET row_security = force;
+CREATE TABLE coll_t (c) AS VALUES ('bar'::text);
+CREATE POLICY coll_p ON coll_t USING (c < ('foo'::text COLLATE "C"));
+ALTER TABLE coll_t ENABLE ROW LEVEL SECURITY;
+SELECT (string_to_array(polqual, ':'))[7] AS inputcollid FROM pg_policy WHERE polrelid = 'coll_t'::regclass;
+   inputcollid    
+------------------
+ inputcollid 950 
+(1 row)
+
+SELECT * FROM coll_t;
+  c  
+-----
+ bar
+(1 row)
+
+ROLLBACK;
+--
 -- Clean up objects
 --
 RESET SESSION AUTHORIZATION;

src/test/regress/sql/rowsecurity.sql

@@ -1087,6 +1087,18 @@ COPY copy_t FROM STDIN; --fail - permission denied.
 RESET SESSION AUTHORIZATION;
 DROP TABLE copy_t;
 
+--
+-- Collation support
+--
+BEGIN;
+SET row_security = force;
+CREATE TABLE coll_t (c) AS VALUES ('bar'::text);
+CREATE POLICY coll_p ON coll_t USING (c < ('foo'::text COLLATE "C"));
+ALTER TABLE coll_t ENABLE ROW LEVEL SECURITY;
+SELECT (string_to_array(polqual, ':'))[7] AS inputcollid FROM pg_policy WHERE polrelid = 'coll_t'::regclass;
+SELECT * FROM coll_t;
+ROLLBACK;
+
 --
 -- Clean up objects
 --