Back-patch 7.3 fix to fully parenthesize UNION/EXCEPT/INTERSECT queries

in ruleutils output.  The previous partial parenthesization was a hack
to get around grammar restrictions that have since been fixed; and as
Sam O'Connor pointed out, there were cases where it didn't work.

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 27abf6ace505ed9bc418a642dfdff1b3584819d2..873137ea66d2de53856a832e7cc5ab34ed4c283b 100644 (file)
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -3,7 +3,7 @@
  *                             back to source text
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.89 2001/11/26 21:15:14 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.89.2.1 2002/06/15 18:38:10 tgl Exp $
  *
  *       This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -116,7 +116,7 @@ static void get_delete_query_def(Query *query, deparse_context *context);
 static void get_utility_query_def(Query *query, deparse_context *context);
 static void get_basic_select_query(Query *query, deparse_context *context);
 static void get_setop_query(Node *setOp, Query *query,
-                               deparse_context *context, bool toplevel);
+                               deparse_context *context);
 static void get_rule_sortgroupclause(SortClause *srt, List *tlist,
                                                 bool force_colno,
                                                 deparse_context *context);
@@ -966,7 +966,7 @@ get_select_query_def(Query *query, deparse_context *context)
         */
        if (query->setOperations)
        {
-               get_setop_query(query->setOperations, query, context, true);
+               get_setop_query(query->setOperations, query, context);
                /* ORDER BY clauses must be simple in this case */
                force_colno = true;
        }
@@ -1123,8 +1123,7 @@ get_basic_select_query(Query *query, deparse_context *context)
 }
 
 static void
-get_setop_query(Node *setOp, Query *query, deparse_context *context,
-                               bool toplevel)
+get_setop_query(Node *setOp, Query *query, deparse_context *context)
 {
        StringInfo      buf = context->buf;
 
@@ -1141,33 +1140,29 @@ get_setop_query(Node *setOp, Query *query, deparse_context *context,
        {
                SetOperationStmt *op = (SetOperationStmt *) setOp;
 
-               /*
-                * Must suppress parens at top level of a setop tree because of
-                * grammar limitations...
-                */
-               if (!toplevel)
-                       appendStringInfo(buf, "(");
-               get_setop_query(op->larg, query, context, false);
+               appendStringInfo(buf, "((");
+               get_setop_query(op->larg, query, context);
                switch (op->op)
                {
                        case SETOP_UNION:
-                               appendStringInfo(buf, " UNION ");
+                               appendStringInfo(buf, ") UNION ");
                                break;
                        case SETOP_INTERSECT:
-                               appendStringInfo(buf, " INTERSECT ");
+                               appendStringInfo(buf, ") INTERSECT ");
                                break;
                        case SETOP_EXCEPT:
-                               appendStringInfo(buf, " EXCEPT ");
+                               appendStringInfo(buf, ") EXCEPT ");
                                break;
                        default:
                                elog(ERROR, "get_setop_query: unexpected set op %d",
                                         (int) op->op);
                }
                if (op->all)
-                       appendStringInfo(buf, "ALL ");
-               get_setop_query(op->rarg, query, context, false);
-               if (!toplevel)
-                       appendStringInfo(buf, ")");
+                       appendStringInfo(buf, "ALL (");
+               else
+                       appendStringInfo(buf, "(");
+               get_setop_query(op->rarg, query, context);
+               appendStringInfo(buf, "))");
        }
        else
        {