Empty set depends

cmd/bosun/conf/rule/rule.go

@@ -630,7 +630,7 @@ func (c *Conf) loadAlert(s *parse.SectionNode) {
 		if err != nil {
 			c.error(err)
 		}
-		if len(depTags.Intersection(tags)) < 1 {
+		if len(depTags) != 0 && len(depTags.Intersection(tags)) < 1 {
 			c.errorf("Depends and crit/warn must share at least one tag.")
 		}
 	}

cmd/bosun/expr/funcs.go

@@ -44,6 +44,23 @@ func tagRemove(args []parse.Node) (parse.Tags, error) {
 	return tags, nil
 }
 
+func seriesFuncTags(args []parse.Node) (parse.Tags, error) {
+	t := make(parse.Tags)
+	text := args[0].(*parse.StringNode).Text
+	if text == "" {
+		return t, nil
+	}
+	ts, err := opentsdb.ParseTags(text)
+	if err != nil {
+		return nil, err
+	}
+
+	for k := range ts {
+		t[k] = struct{}{}
+	}
+	return t, nil
+}
+
 func tagTranspose(args []parse.Node) (parse.Tags, error) {
 	tags := make(parse.Tags)
 	sp := strings.Split(args[1].(*parse.StringNode).Text, ",")
@@ -309,7 +326,7 @@ var builtins = map[string]parse.Func{
 		VArgsPos:  1,
 		VArgsOmit: true,
 		Return:    models.TypeSeriesSet,
-		Tags:      tagFirst,
+		Tags:      seriesFuncTags,
 		F:         SeriesFunc,
 	},
 	"sort": {

cmd/bosun/sched/check.go

@@ -614,7 +614,7 @@ func markDependenciesUnevaluated(events map[models.AlertKey]*models.Event, deps
 			continue
 		}
 		for _, dep := range deps {
-			if dep.Group.Overlaps(ak.Group()) {
+			if len(dep.Group) == 0 || dep.Group.Overlaps(ak.Group()) {
 				ev.Unevaluated = true
 				unevalCount++
 			}