From 01e0cbc4f687325b825e7953f99f0b16a2bd4e96 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 15 Feb 2017 14:43:59 -0500
Subject: [PATCH] Fix YA unwanted behavioral difference with
operator_precedence_warning.
Jeff Janes noted that the error cursor position shown for some errors
would vary when operator_precedence_warning is turned on. We'd prefer
that option to have no undocumented effects, so this isn't desirable.
To fix, make sure that an AEXPR_PAREN node has the same exprLocation
as its child node.
(Note: it would be a little cheaper to use @2 here instead of an
exprLocation call, but there are cases where that wouldn't produce
the identical answer, so don't do it like that.)
Back-patch to 9.5 where this feature was introduced.
Discussion: https://postgr.es/m/CAMkU=1ykK+VhhcQ4Ky8KBo9FoaUJH3f3rDQB8TkTXi-ZsBRUkQ@mail.gmail.com
---
src/backend/parser/gram.y | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 5cb82977d5d..07cc81ee764 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -12764,7 +12764,10 @@ c_expr: columnref { $$ = $1; }
* AEXPR_PAREN nodes wrapping all explicitly
* parenthesized subexpressions; this prevents bogus
* warnings from being issued when the ordering has
- * been forced by parentheses.
+ * been forced by parentheses. Take care that an
+ * AEXPR_PAREN node has the same exprLocation as its
+ * child, so as not to cause surprising changes in
+ * error cursor positioning.
*
* In principle we should not be relying on a GUC to
* decide whether to insert AEXPR_PAREN nodes.
@@ -12773,7 +12776,8 @@ c_expr: columnref { $$ = $1; }
* we'd just as soon not waste cycles on dummy parse
* nodes if we don't have to.
*/
- $$ = (Node *) makeA_Expr(AEXPR_PAREN, NIL, $2, NULL, @1);
+ $$ = (Node *) makeA_Expr(AEXPR_PAREN, NIL, $2, NULL,
+ exprLocation($2));
}
else
$$ = $2;
--
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