From c1943dbaefb9446da01281ea01b740a13f8d5a2f Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 6 Jun 2008 17:59:29 +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 4393f91c41f..3754b4981ed 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.274 2008/05/12 00:00:51 alvherre Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.275 2008/06/06 17:59:29 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -4479,10 +4479,19 @@ 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 */ }