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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2008-06-06 17:59:53 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2008-06-06 17:59:53 +0000 |
| commit | 7521bdaad982637f3478a3f53be368758fbd3138 (patch) | |
| tree | 308e3a064f2297d4d33cb115c4d45e2667a4edb5 | |
| parent | 5766e91752d8e8ea5fe6b7274648ba388859ebfb (diff) | |
| download | postgresql-7521bdaad982637f3478a3f53be368758fbd3138.tar.gz postgresql-7521bdaad982637f3478a3f53be368758fbd3138.zip | |
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 c8fcff14809..119a9c20db0 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -3,7 +3,7 @@ * back to source text * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.207.2.8 2008/01/06 01:03:31 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.207.2.9 2008/06/06 17:59:53 tgl Exp $ * * This software is copyrighted by Jan Wieck - Hamburg. * @@ -4042,10 +4042,19 @@ 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 */ } |