v3-0001-vgc-where-current-of-fix.patch

diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 84deed9a..d9845358 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -595,6 +595,14 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
 										 ACL_DELETE);
 	nsitem = pstate->p_target_nsitem;
 
+	/* disallow DELETE ... WHERE CURRENT OF on a view */
+	if (stmt->whereClause &&
+		IsA(stmt->whereClause, CurrentOfExpr) &&
+		pstate->p_target_relation->rd_rel->relkind == RELKIND_VIEW)
+		ereport(ERROR,
+				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("WHERE CURRENT OF on a view is not implemented"));
+
 	/* there's no DISTINCT in DELETE */
 	qry->distinctClause = NIL;
 
@@ -2868,6 +2876,14 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 										 true,
 										 ACL_UPDATE);
 
+	/* disallow UPDATE ... WHERE CURRENT OF on a view */
+	if (stmt->whereClause &&
+		IsA(stmt->whereClause, CurrentOfExpr) &&
+		pstate->p_target_relation->rd_rel->relkind == RELKIND_VIEW)
+		ereport(ERROR,
+				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("WHERE CURRENT OF on a view is not implemented"));
+
 	if (stmt->forPortionOf)
 		qry->forPortionOf = transformForPortionOfClause(pstate,
 														qry->resultRelation,
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 4bf4aa0d..9aa7ef60 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1514,25 +1514,6 @@ replace_rte_variables_mutator(Node *node,
 		}
 		/* otherwise fall through to copy the var normally */
 	}
-	else if (IsA(node, CurrentOfExpr))
-	{
-		CurrentOfExpr *cexpr = (CurrentOfExpr *) node;
-
-		if (cexpr->cvarno == context->target_varno &&
-			context->sublevels_up == 0)
-		{
-			/*
-			 * We get here if a WHERE CURRENT OF expression turns out to apply
-			 * to a view.  Someday we might be able to translate the
-			 * expression to apply to an underlying table of the view, but
-			 * right now it's not implemented.
-			 */
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("WHERE CURRENT OF on a view is not implemented")));
-		}
-		/* otherwise fall through to copy the expr normally */
-	}
 	else if (IsA(node, Query))
 	{
 		/* Recurse into RTE subquery or not-yet-planned sublink subquery */
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index fc41c480..58cdf310 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1723,3 +1723,57 @@ select * from gtest33 where b is null;
 
 reset constraint_exclusion;
 drop table gtest33;
+create table gtest_cursor (id int primary key, a int, b int generated always as (a * 2) virtual);
+insert into gtest_cursor values (1, 10), (2, 20), (3, 30);
+-- UPDATE via cursor
+begin;
+declare cur1 cursor for select * from gtest_cursor order by id for update;
+fetch 1 from cur1;
+ id | a  | b  
+----+----+----
+  1 | 10 | 20
+(1 row)
+
+update gtest_cursor set a = 99 where current of cur1;
+select * from gtest_cursor order by id;
+ id | a  |  b  
+----+----+-----
+  1 | 99 | 198
+  2 | 20 |  40
+  3 | 30 |  60
+(3 rows)
+
+commit;
+-- DELETE via cursor
+begin;
+declare cur2 cursor for select * from gtest_cursor order by id for update;
+fetch 1 from cur2;
+ id | a  |  b  
+----+----+-----
+  1 | 99 | 198
+(1 row)
+
+delete from gtest_cursor where current of cur2;
+select * from gtest_cursor order by id;
+ id | a  | b  
+----+----+----
+  2 | 20 | 40
+  3 | 30 | 60
+(2 rows)
+
+commit;
+-- WHERE CURRENT OF via a view on a table with VGC (should fail)
+create view gtest_cursor_view as select * from gtest_cursor;
+begin;
+declare cur3 cursor for select * from gtest_cursor_view for update;
+fetch 1 from cur3;
+ id | a  | b  
+----+----+----
+  2 | 20 | 40
+(1 row)
+
+update gtest_cursor_view set a = 55 where current of cur3;  -- fail
+ERROR:  WHERE CURRENT OF on a view is not implemented
+rollback;
+drop view gtest_cursor_view;
+drop table gtest_cursor;
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
index 9b32413e..48daf31a 100644
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -906,3 +906,33 @@ select * from gtest33 where b is null;
 
 reset constraint_exclusion;
 drop table gtest33;
+
+create table gtest_cursor (id int primary key, a int, b int generated always as (a * 2) virtual);
+insert into gtest_cursor values (1, 10), (2, 20), (3, 30);
+
+-- UPDATE via cursor
+begin;
+declare cur1 cursor for select * from gtest_cursor order by id for update;
+fetch 1 from cur1;
+update gtest_cursor set a = 99 where current of cur1;
+select * from gtest_cursor order by id;
+commit;
+
+-- DELETE via cursor
+begin;
+declare cur2 cursor for select * from gtest_cursor order by id for update;
+fetch 1 from cur2;
+delete from gtest_cursor where current of cur2;
+select * from gtest_cursor order by id;
+commit;
+
+-- WHERE CURRENT OF via a view on a table with VGC (should fail)
+create view gtest_cursor_view as select * from gtest_cursor;
+begin;
+declare cur3 cursor for select * from gtest_cursor_view for update;
+fetch 1 from cur3;
+update gtest_cursor_view set a = 55 where current of cur3;  -- fail
+rollback;
+drop view gtest_cursor_view;
+
+drop table gtest_cursor;