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>

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 20384db2fb8e28a4220a43e83025758daab1a2eb..ad338d3ddbe0f039fc2a4f83ffc0121fc64cffb7 100644 (file)
--- 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)
        {