From f67b8aeab3a543d156787de7311d4a98f228ab9f Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 2 Dec 2013 20:28:56 -0500 Subject: Fix crash in assign_collations_walker for EXISTS with empty SELECT list. We (I think I, actually) forgot about this corner case while coding collation resolution. Per bug #8648 from Arjen Nienhuis. --- src/backend/parser/parse_collate.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'src/backend/parser/parse_collate.c') diff --git a/src/backend/parser/parse_collate.c b/src/backend/parser/parse_collate.c index f0cd3f88d23..ec606ebcac7 100644 --- a/src/backend/parser/parse_collate.c +++ b/src/backend/parser/parse_collate.c @@ -564,16 +564,22 @@ assign_collations_walker(Node *node, assign_collations_context *context) * SubLink. Act as though the Query returns its first output * column, which indeed is what it does for EXPR_SUBLINK and * ARRAY_SUBLINK cases. In the cases where the SubLink - * returns boolean, this info will be ignored. + * returns boolean, this info will be ignored. Special case: + * in EXISTS, the Query might return no columns, in which case + * we need do nothing. * * We needn't recurse, since the Query is already processed. */ Query *qtree = (Query *) node; TargetEntry *tent; + if (qtree->targetList == NIL) + return false; tent = (TargetEntry *) linitial(qtree->targetList); Assert(IsA(tent, TargetEntry)); - Assert(!tent->resjunk); + if (tent->resjunk) + return false; + collation = exprCollation((Node *) tent->expr); /* collation doesn't change if it's converted to array */ strength = COLLATE_IMPLICIT; -- cgit v1.2.3