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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2008-06-06 18:00:09 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2008-06-06 18:00:09 +0000 |
| commit | c760d70af47d648833c03d764255c31b8d554ee3 (patch) | |
| tree | ca256aeea6f9ce1e8c63e417a818609c8d6feb27 /src/backend/utils/adt/ruleutils.c | |
| parent | bef81252ca29ed71299d5fe5c3ade06c65e62802 (diff) | |
| download | postgresql-c760d70af47d648833c03d764255c31b8d554ee3.tar.gz postgresql-c760d70af47d648833c03d764255c31b8d554ee3.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.
Diffstat (limited to 'src/backend/utils/adt/ruleutils.c')
| -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 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 */ } |