Make constant-folding produce sane output for COALESCE(NULL,NULL),

that is a plain NULL and not a COALESCE with no inputs.  Fixes crash
reported by Michael Williamson.
This commit is contained in:
Tom Lane 2005-04-10 20:57:32 +00:00
parent 6985592967
commit acde8b3cab
1 changed files with 5 additions and 1 deletions

View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.193 2005/04/06 16:34:06 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.194 2005/04/10 20:57:32 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@ -1788,6 +1788,10 @@ eval_const_expressions_mutator(Node *node,
newargs = lappend(newargs, e);
}
/* If all the arguments were constant null, the result is just null */
if (newargs == NIL)
return (Node *) makeNullConst(coalesceexpr->coalescetype);
newcoalesce = makeNode(CoalesceExpr);
newcoalesce->coalescetype = coalesceexpr->coalescetype;
newcoalesce->args = newargs;