fix(failover): keep the aliased model of a warm target loaded

The warm list held target names as the chain lists them. For an alias
target that is the alias, but the preloader loads the alias stub (no
backend, no model) and the eviction guard compares against loaded
model names, which never include an alias. A warm alias target was
neither preloaded nor protected from eviction.

Report the model that serves each warm target instead.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-5-5 [Claude Code]

core/services/failover/manager.go

@@ -87,7 +87,10 @@ type Manager struct {
 }
 
 type targetState struct {
-	name          string
+	name string
+	// serving is the model that serves this target: its own name, or the
+	// model an alias points to. Model loading and eviction only know it.
+	serving       string
 	kind          Kind
 	warm          bool
 	state         TargetState
@@ -196,6 +199,7 @@ func (m *Manager) syncLocked() {
 				continue
 			}
 			ts.kind = KindOf(tc)
+			ts.serving = tc.Name
 			if t.Warm && ts.kind == KindLocal {
 				ts.warm = true
 			}
@@ -224,9 +228,9 @@ func (m *Manager) syncLocked() {
 		m.recomputeLocked(ch, "")
 	}
 	var warm []string
-	for name, ts := range m.targets {
-		if ts.warm {
-			warm = append(warm, name)
+	for _, ts := range m.targets {
+		if ts.warm && ts.serving != "" && !slices.Contains(warm, ts.serving) {
+			warm = append(warm, ts.serving)
 		}
 	}
 	sort.Strings(warm)

core/services/failover/manager_test.go

@@ -248,6 +248,18 @@ var _ = Describe("Manager", func() {
 		Expect(m.WarmTargets()).To(Equal([]string{"b"}))
 	})
 
+	It("reports the model an alias target serves from as warm, not the alias", func() {
+		var got []string
+		m = New(src, WithClock(clock), WithOnWarmChanged(func(w []string) { got = w }))
+		// The preloader and the eviction guard work on loaded model names; an
+		// alias is never loaded under its own name.
+		src.Put(config.ModelConfig{Name: "al", Alias: "b"})
+		src.Put(chainCfg("chain", nil, t("a"), warmT("al")))
+		m.Sync()
+		Expect(got).To(Equal([]string{"b"}))
+		Expect(m.WarmTargets()).To(Equal([]string{"b"}))
+	})
+
 	It("closes a subscription on cancel", func() {
 		events, cancel := m.Subscribe(1)
 		cancel()