From c760d70af47d648833c03d764255c31b8d554ee3 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 6 Jun 2008 18:00:09 +0000 Subject: [PATCH] Fix pg_get_ruledef() so that negative numeric constants are parenthesized. This is needed because :: casting binds more tightly than minus, so for example -1::integer is not the same as (-1)::integer, and there are cases where the difference is important. In particular this caused a failure in SELECT DISTINCT ... ORDER BY ... where expressions that should have matched were seen as different by the parser; but I suspect that there could be other cases where failure to parenthesize leads to subtler semantic differences in reloaded rules. Per report from Alexandr Popov. --- src/backend/utils/adt/ruleutils.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index 0790ea76ca6..b5f9fcf5b0a 100644 --- 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 1.157.2.6 2008/01/06 01:03:46 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.157.2.7 2008/06/06 18:00:09 tgl Exp $ * * This software is copyrighted by Jan Wieck - Hamburg. * @@ -3518,10 +3518,19 @@ get_const_expr(Const *constval, deparse_context *context, int showtype) * In reality we only need to defend against infinity and * NaN, so we need not get too crazy about pattern * matching here. + * + * There is a special-case gotcha: if the constant is signed, + * we need to parenthesize it, else the parser might see a + * leading plus/minus as binding less tightly than adjacent + * operators --- particularly, the cast that we might attach + * below. */ if (strspn(extval, "0123456789+-eE.") == strlen(extval)) { - appendStringInfoString(buf, extval); + if (extval[0] == '+' || extval[0] == '-') + appendStringInfo(buf, "(%s)", extval); + else + appendStringInfoString(buf, extval); if (strcspn(extval, "eE.") != strlen(extval)) isfloat = true; /* it looks like a float */ }