From 29028762a96741647681495fc16ede97d743107c Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 10 Apr 2005 20:58:03 +0000 Subject: [PATCH] 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. --- src/backend/optimizer/util/clauses.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index d8809a5252d..ae0c387e69a 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.154.2.2 2004/01/28 00:05:25 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.154.2.3 2005/04/10 20:58:03 tgl Exp $ * * HISTORY * AUTHOR DATE MAJOR EVENT @@ -1553,6 +1553,10 @@ eval_const_expressions_mutator(Node *node, List *active_fns) FastAppend(&newargs, e); } + /* If all the arguments were constant null, the result is just null */ + if (FastListValue(&newargs) == NIL) + return (Node *) makeNullConst(coalesceexpr->coalescetype); + newcoalesce = makeNode(CoalesceExpr); newcoalesce->coalescetype = coalesceexpr->coalescetype; newcoalesce->args = FastListValue(&newargs);