[优化] 重构升级处理逻辑，添加备份二进制文件移除功能，更新相关测试以验证新行为

openflare_agent/internal/updater/restart_unix.go

@@ -11,30 +11,26 @@ import (
 
 func replaceAndRestart(execPath string, tmpPath string) error {
 	backupPath := execPath + ".bak"
-	err := os.Remove(backupPath)
-	if err != nil {
-		slog.Error("remove backup binary failed", "path", backupPath, "error", err)
+	if err := removeBackupBinary(backupPath); err != nil {
 		return err
 	}
 	if err := os.Rename(execPath, backupPath); err != nil {
-		err := os.Remove(tmpPath)
-		if err != nil {
+		renameErr := err
+		if err := os.Remove(tmpPath); err != nil && !os.IsNotExist(err) {
 			slog.Error("remove tmp binary failed", "path", tmpPath, "error", err)
-			return err
+			return fmt.Errorf("backup current binary: %w; remove tmp binary: %v", renameErr, err)
 		}
-		return fmt.Errorf("backup current binary: %w", err)
+		return fmt.Errorf("backup current binary: %w", renameErr)
 	}
 	if err := os.Rename(tmpPath, execPath); err != nil {
-		err := os.Rename(backupPath, execPath)
-		if err != nil {
+		replaceErr := err
+		if err := os.Rename(backupPath, execPath); err != nil {
 			slog.Error("restore backup binary failed", "path", backupPath, "error", err)
-			return err
+			return fmt.Errorf("replace binary: %w; restore backup binary: %v", replaceErr, err)
 		}
-		return fmt.Errorf("replace binary: %w", err)
+		return fmt.Errorf("replace binary: %w", replaceErr)
 	}
-	err = os.Remove(backupPath)
-	if err != nil {
-		slog.Error("remove backup binary failed", "path", backupPath, "error", err)
+	if err := removeBackupBinary(backupPath); err != nil {
 		return err
 	}
 	if err := syscall.Exec(execPath, os.Args, os.Environ()); err != nil {
@@ -42,3 +38,14 @@ func replaceAndRestart(execPath string, tmpPath string) error {
 	}
 	return fmt.Errorf("unreachable after exec")
 }
+
+func removeBackupBinary(path string) error {
+	if err := os.Remove(path); err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		slog.Error("remove backup binary failed", "path", path, "error", err)
+		return err
+	}
+	return nil
+}

openflare_agent/internal/updater/restart_unix_test.go

@@ -0,0 +1,15 @@
+//go:build !windows
+
+package updater
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+func TestRemoveBackupBinaryIgnoresMissingFile(t *testing.T) {
+	backupPath := filepath.Join(t.TempDir(), "openflare-agent.bak")
+	if err := removeBackupBinary(backupPath); err != nil {
+		t.Fatalf("expected missing backup cleanup to be ignored: %v", err)
+	}
+}