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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2008-06-06 17:59:45 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2008-06-06 17:59:45 +0000 |
| commit | 7340246aee367264083357ed55cd47bc155dea37 (patch) | |
| tree | 3fd5778a2e50ab08f9484290bfb45cd0e8e3f654 | |
| parent | b33c19746cc1e936d8ba5ff836ddab88f76a0d1b (diff) | |
| download | postgresql-7340246aee367264083357ed55cd47bc155dea37.tar.gz | |
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.
| -rw-r--r-- | src/backend/utils/adt/ruleutils.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index 47d56aaf44..ff8b73bade 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -2,7 +2,7 @@ * ruleutils.c - Functions to convert stored expressions/querytrees * back to source text * - * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.235.2.5 2008/05/03 23:19:33 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.235.2.6 2008/06/06 17:59:45 tgl Exp $ **********************************************************************/ #include "postgres.h" @@ -4229,10 +4229,19 @@ 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 */ } |