Changeset: c02778d25f57 for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=c02778d25f57
Modified Files:
monetdb5/extras/jaql/json.c
Branch: Oct2012
Log Message:
unwrap: allow empty input
people (me) can write queries that yield in an empty set, in which case,
we shouldn't abort, but just return that empty set
diffs (32 lines):
diff --git a/monetdb5/extras/jaql/json.c b/monetdb5/extras/jaql/json.c
--- a/monetdb5/extras/jaql/json.c
+++ b/monetdb5/extras/jaql/json.c
@@ -1408,7 +1408,27 @@ JSONunwrap(Client cntxt, MalBlkPtr mb, M
b = BATselect(BATmirror(jb.array), BUNhead(bi, p), NULL);
b = BATsemijoin(jb.kind, b);
bi = bat_iterator(b);
- assert(BATcount(b) != 0);
+
+ if (BATcount(b) == 0) {
+ /* input empty, return empty result */
+ unloadbats();
+ switch (tpe->vtype) {
+ case TYPE_str:
+ r = BATnew(TYPE_oid, TYPE_str, 0);
+ break;
+ case TYPE_dbl:
+ r = BATnew(TYPE_oid, TYPE_dbl, 0);
+ break;
+ case TYPE_lng:
+ r = BATnew(TYPE_oid, TYPE_lng, 0);
+ break;
+ default:
+ assert(0); /* should not happen, checked above
*/
+ }
+ BBPkeepref(r->batCacheid);
+ *ret = r->batCacheid;
+ return MAL_SUCCEED;
+ }
/* special case for when the argument is a single array */
c = BATantiuselect_(b, "a", NULL, TRUE, TRUE);
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