fix(usbgadget): do not panic if a change isn't found

internal/usbgadget/changeset_resolver.go

@@ -48,6 +48,11 @@ func (c *ChangeSetResolver) doResolveChanges(initial bool) error {
 
 	for _, key := range c.orderedChanges {
 		change := c.changesMap[key.(string)]
+		if change == nil {
+			c.l.Error().Str("key", key.(string)).Msg("fileChange not found")
+			continue
+		}
+
 		if !initial {
 			change.ResetActionResolution()
 		}

internal/usbgadget/config.go

@@ -177,12 +177,7 @@ func (u *UsbGadget) Init() error {
 
 	u.udc = udcs[0]
 
-	err := u.WithTransaction(func() error {
-		u.tx.MountConfigFS()
-		u.tx.CreateConfigPath()
-		u.tx.WriteGadgetConfig()
-		return nil
-	})
+	err := u.configureUsbGadget()
 	if err != nil {
 		return u.logError("unable to initialize USB stack", err)
 	}
@@ -196,13 +191,19 @@ func (u *UsbGadget) UpdateGadgetConfig() error {
 
 	u.loadGadgetConfig()
 
-	err := u.WithTransaction(func() error {
-		u.tx.WriteGadgetConfig()
-		return nil
-	})
+	err := u.configureUsbGadget()
 	if err != nil {
 		return u.logError("unable to update gadget config", err)
 	}
 
 	return nil
 }
+
+func (u *UsbGadget) configureUsbGadget() error {
+	return u.WithTransaction(func() error {
+		u.tx.MountConfigFS()
+		u.tx.CreateConfigPath()
+		u.tx.WriteGadgetConfig()
+		return nil
+	})
+}