fix(outboundgroup): avoid selecting timeout nodes when alive nodes exist

adapter/outboundgroup/fallback.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"sync"
 	"time"
 
 	"github.com/metacubex/mihomo/common/callback"
@@ -15,6 +16,7 @@ import (
 
 type Fallback struct {
 	*GroupBase
+	stateMux       sync.RWMutex
 	disableUDP     bool
 	testUrl        string
 	selected       string
@@ -89,7 +91,7 @@ func (f *Fallback) MarshalJSON() ([]byte, error) {
 		"all":            all,
 		"testUrl":        f.testUrl,
 		"expectedStatus": f.expectedStatus,
-		"fixed":          f.selected,
+		"fixed":          f.getSelected(),
 		"hidden":         f.Hidden,
 		"icon":           f.Icon,
 	})
@@ -103,19 +105,24 @@ func (f *Fallback) Unwrap(metadata *C.Metadata, touch bool) C.Proxy {
 
 func (f *Fallback) findAliveProxy(touch bool) C.Proxy {
 	proxies := f.GetProxies(touch)
-	for _, proxy := range proxies {
-		if len(f.selected) == 0 {
+	selected := f.getSelected()
+
+	if len(selected) != 0 {
+		for _, proxy := range proxies {
+			if proxy.Name() != selected {
+				continue
+			}
 			if proxy.AliveForTestUrl(f.testUrl) {
 				return proxy
 			}
-		} else {
-			if proxy.Name() == f.selected {
-				if proxy.AliveForTestUrl(f.testUrl) {
-					return proxy
-				} else {
-					f.selected = ""
-				}
-			}
+			f.clearSelectedIf(selected)
+			break
+		}
+	}
+
+	for _, proxy := range proxies {
+		if proxy.AliveForTestUrl(f.testUrl) {
+			return proxy
 		}
 	}
 
@@ -135,7 +142,7 @@ func (f *Fallback) Set(name string) error {
 		return errors.New("proxy not exist")
 	}
 
-	f.selected = name
+	f.setSelected(name)
 	if !p.AliveForTestUrl(f.testUrl) {
 		ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*time.Duration(5000))
 		defer cancel()
@@ -147,7 +154,28 @@ func (f *Fallback) Set(name string) error {
 }
 
 func (f *Fallback) ForceSet(name string) {
+	f.setSelected(name)
+}
+
+func (f *Fallback) getSelected() string {
+	f.stateMux.RLock()
+	defer f.stateMux.RUnlock()
+
+	return f.selected
+}
+
+func (f *Fallback) setSelected(name string) {
+	f.stateMux.Lock()
 	f.selected = name
+	f.stateMux.Unlock()
+}
+
+func (f *Fallback) clearSelectedIf(selected string) {
+	f.stateMux.Lock()
+	if f.selected == selected {
+		f.selected = ""
+	}
+	f.stateMux.Unlock()
 }
 
 func (f *Fallback) Providers() []P.ProxyProvider {

adapter/outboundgroup/groupbase.go

@@ -224,7 +224,7 @@ func (gb *GroupBase) URLTest(ctx context.Context, url string, expectedStatus uti
 		wg.Add(1)
 		go func() {
 			delay, err := proxy.URLTest(ctx, url, expectedStatus)
-			if err == nil {
+			if err == nil && proxy.AliveForTestUrl(url) {
 				lock.Lock()
 				mp[proxy.Name()] = delay
 				lock.Unlock()

adapter/outboundgroup/urltest.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"sync"
 	"time"
 
 	"github.com/metacubex/mihomo/common/callback"
@@ -24,6 +25,7 @@ func urlTestWithTolerance(tolerance uint16) urlTestOption {
 
 type URLTest struct {
 	*GroupBase
+	stateMux       sync.RWMutex
 	selected       string
 	testUrl        string
 	expectedStatus string
@@ -55,7 +57,9 @@ func (u *URLTest) Set(name string) error {
 }
 
 func (u *URLTest) ForceSet(name string) {
+	u.stateMux.Lock()
 	u.selected = name
+	u.stateMux.Unlock()
 	u.fastSingle.Reset()
 }
 
@@ -109,24 +113,29 @@ func (u *URLTest) healthCheck() {
 func (u *URLTest) fast(touch bool) C.Proxy {
 	elm, _, shared := u.fastSingle.Do(func() (C.Proxy, error) {
 		proxies := u.GetProxies(touch)
-		if u.selected != "" {
+		selected, fastNode := u.snapshotState()
+
+		if selected != "" {
 			for _, proxy := range proxies {
 				if !proxy.AliveForTestUrl(u.testUrl) {
 					continue
 				}
-				if proxy.Name() == u.selected {
-					u.fastNode = proxy
+				if proxy.Name() == selected {
+					u.setFastNode(proxy)
 					return proxy, nil
 				}
 			}
 		}
 
-		fast := proxies[0]
-		minDelay := fast.LastDelayForTestUrl(u.testUrl)
-		fastNotExist := true
+		var (
+			fast         C.Proxy
+			fastDelay    uint16
+			hasAliveFast bool
+			fastNotExist = true
+		)
 
-		for _, proxy := range proxies[1:] {
-			if u.fastNode != nil && proxy.Name() == u.fastNode.Name() {
+		for _, proxy := range proxies {
+			if fastNode != nil && proxy.Name() == fastNode.Name() {
 				fastNotExist = false
 			}
 
@@ -135,17 +144,25 @@ func (u *URLTest) fast(touch bool) C.Proxy {
 			}
 
 			delay := proxy.LastDelayForTestUrl(u.testUrl)
-			if delay < minDelay {
+			if !hasAliveFast || delay < fastDelay {
 				fast = proxy
-				minDelay = delay
+				fastDelay = delay
+				hasAliveFast = true
 			}
-
 		}
-		// tolerance
-		if u.fastNode == nil || fastNotExist || !u.fastNode.AliveForTestUrl(u.testUrl) || u.fastNode.LastDelayForTestUrl(u.testUrl) > fast.LastDelayForTestUrl(u.testUrl)+u.tolerance {
-			u.fastNode = fast
+
+		// Do not fall back to timeout nodes when at least one alive node exists.
+		if hasAliveFast {
+			// tolerance
+			if fastNode == nil || fastNotExist || !fastNode.AliveForTestUrl(u.testUrl) || fastNode.LastDelayForTestUrl(u.testUrl) > fastDelay+u.tolerance {
+				fastNode = fast
+			}
+		} else if fastNode == nil || fastNotExist || !fastNode.AliveForTestUrl(u.testUrl) {
+			fastNode = proxies[0]
 		}
-		return u.fastNode, nil
+
+		u.setFastNode(fastNode)
+		return fastNode, nil
 	})
 	if shared && touch { // a shared fastSingle.Do() may cause providers untouched, so we touch them again
 		u.Touch()
@@ -154,6 +171,26 @@ func (u *URLTest) fast(touch bool) C.Proxy {
 	return elm
 }
 
+func (u *URLTest) snapshotState() (string, C.Proxy) {
+	u.stateMux.RLock()
+	defer u.stateMux.RUnlock()
+
+	return u.selected, u.fastNode
+}
+
+func (u *URLTest) getSelected() string {
+	u.stateMux.RLock()
+	defer u.stateMux.RUnlock()
+
+	return u.selected
+}
+
+func (u *URLTest) setFastNode(proxy C.Proxy) {
+	u.stateMux.Lock()
+	u.fastNode = proxy
+	u.stateMux.Unlock()
+}
+
 // SupportUDP implements C.ProxyAdapter
 func (u *URLTest) SupportUDP() bool {
 	if u.disableUDP {
@@ -179,7 +216,7 @@ func (u *URLTest) MarshalJSON() ([]byte, error) {
 		"all":            all,
 		"testUrl":        u.testUrl,
 		"expectedStatus": u.expectedStatus,
-		"fixed":          u.selected,
+		"fixed":          u.getSelected(),
 		"hidden":         u.Hidden,
 		"icon":           u.Icon,
 	})
@@ -194,7 +231,11 @@ func (u *URLTest) Proxies() []C.Proxy {
 }
 
 func (u *URLTest) URLTest(ctx context.Context, url string, expectedStatus utils.IntRanges[uint16]) (map[string]uint16, error) {
-	return u.GroupBase.URLTest(ctx, u.testUrl, expectedStatus)
+	delays, err := u.GroupBase.URLTest(ctx, u.testUrl, expectedStatus)
+	// URL tests update alive/delay history; reset cache so next routing picks fresh best node.
+	u.fastSingle.Reset()
+	_ = u.fast(false)
+	return delays, err
 }
 
 func parseURLTestOption(config map[string]any) []urlTestOption {