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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2008-06-06 17:59:29 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2008-06-06 17:59:29 +0000 |
| commit | c1943dbaefb9446da01281ea01b740a13f8d5a2f (patch) | |
| tree | 87c1982a29980e02d90191538dd9f46320bdd99d /src | |
| parent | 700af334cccdf5e817fd1b16d4afb86322905980 (diff) | |
| download | postgresql-c1943dbaefb9446da01281ea01b740a13f8d5a2f.tar.gz postgresql-c1943dbaefb9446da01281ea01b740a13f8d5a2f.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')
| -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 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 */ } |