From 05104f693646c0a4ae446e79cb89057497da17e4 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 3 Jun 2016 19:12:29 -0400
Subject: [PATCH] Fix grammar's AND/OR flattening to work with
operator_precedence_warning.
It'd be good for "(x AND y) AND z" to produce a three-child AND node
whether or not operator_precedence_warning is on, but that failed to
happen when it's on because makeAndExpr() didn't look through the added
AEXPR_PAREN node. This has no effect on generated plans because prepqual.c
would flatten the AND nest anyway; but it does affect the number of parens
printed in ruleutils.c, for example. I'd already fixed some similar
hazards in parse_expr.c in commit abb164655, but didn't think to search
gram.y for problems of this ilk. Per gripe from Jean-Pierre Pelletier.
Report: <fa0535ec6d6428cfec40c7e8a6d11156@mail.gmail.com>
---
src/backend/parser/gram.y | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 20384db2fb8..ad338d3ddbe 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -14643,10 +14643,16 @@ doNegateFloat(Value *v)
static Node *
makeAndExpr(Node *lexpr, Node *rexpr, int location)
{
+ Node *lexp = lexpr;
+
+ /* Look through AEXPR_PAREN nodes so they don't affect flattening */
+ while (IsA(lexp, A_Expr) &&
+ ((A_Expr *) lexp)->kind == AEXPR_PAREN)
+ lexp = ((A_Expr *) lexp)->lexpr;
/* Flatten "a AND b AND c ..." to a single BoolExpr on sight */
- if (IsA(lexpr, BoolExpr))
+ if (IsA(lexp, BoolExpr))
{
- BoolExpr *blexpr = (BoolExpr *) lexpr;
+ BoolExpr *blexpr = (BoolExpr *) lexp;
if (blexpr->boolop == AND_EXPR)
{
@@ -14660,10 +14666,16 @@ makeAndExpr(Node *lexpr, Node *rexpr, int location)
static Node *
makeOrExpr(Node *lexpr, Node *rexpr, int location)
{
+ Node *lexp = lexpr;
+
+ /* Look through AEXPR_PAREN nodes so they don't affect flattening */
+ while (IsA(lexp, A_Expr) &&
+ ((A_Expr *) lexp)->kind == AEXPR_PAREN)
+ lexp = ((A_Expr *) lexp)->lexpr;
/* Flatten "a OR b OR c ..." to a single BoolExpr on sight */
- if (IsA(lexpr, BoolExpr))
+ if (IsA(lexp, BoolExpr))
{
- BoolExpr *blexpr = (BoolExpr *) lexpr;
+ BoolExpr *blexpr = (BoolExpr *) lexp;
if (blexpr->boolop == OR_EXPR)
{
--
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