fix: fetcher does not start the pull loop when local file parsing errors occur and the first remote update fails

component/resource/fetcher.go

@@ -3,6 +3,7 @@ package resource
 import (
 	"context"
 	"os"
+	"sync"
 	"time"
 
 	"github.com/metacubex/mihomo/common/utils"
@@ -27,6 +28,7 @@ type Fetcher[V any] struct {
 	interval     time.Duration
 	onUpdate     func(V)
 	watcher      *fswatch.Watcher
+	loadBufMutex sync.Mutex
 }
 
 func (f *Fetcher[V]) Name() string {
@@ -46,17 +48,11 @@ func (f *Fetcher[V]) UpdatedAt() time.Time {
 }
 
 func (f *Fetcher[V]) Initial() (V, error) {
-	var (
-		buf      []byte
-		contents V
-		err      error
-	)
-
 	if stat, fErr := os.Stat(f.vehicle.Path()); fErr == nil {
 		// local file exists, use it first
-		buf, err = os.ReadFile(f.vehicle.Path())
+		buf, err := os.ReadFile(f.vehicle.Path())
 		modTime := stat.ModTime()
-		contents, _, err = f.loadBuf(buf, utils.MakeHash(buf), false)
+		contents, _, err := f.loadBuf(buf, utils.MakeHash(buf), false)
 		f.updatedAt = modTime // reset updatedAt to file's modTime
 
 		if err == nil {
@@ -69,15 +65,18 @@ func (f *Fetcher[V]) Initial() (V, error) {
 	}
 
 	// parse local file error, fallback to remote
-	contents, _, err = f.Update()
+	contents, _, updateErr := f.Update()
 
+	// start the pull loop even if f.Update() failed
+	err := f.startPullLoop(false)
 	if err != nil {
 		return lo.Empty[V](), err
 	}
-	err = f.startPullLoop(false)
-	if err != nil {
-		return lo.Empty[V](), err
+
+	if updateErr != nil {
+		return lo.Empty[V](), updateErr
 	}
+
 	return contents, nil
 }
 
@@ -94,6 +93,9 @@ func (f *Fetcher[V]) SideUpdate(buf []byte) (V, bool, error) {
 }
 
 func (f *Fetcher[V]) loadBuf(buf []byte, hash utils.HashType, updateFile bool) (V, bool, error) {
+	f.loadBufMutex.Lock()
+	defer f.loadBufMutex.Unlock()
+
 	now := time.Now()
 	if f.hash.Equal(hash) {
 		if updateFile {