Introduce user.updateUser

Unify updatePassword and updateRealname into a single function. This
allows "user update" to be atomic.

service.go

@@ -775,19 +775,22 @@ func handleUserUpdate(dc *downstreamConn, params []string) error {
 		return err
 	}
 
+	// copy the user record because we'll mutate it
+	record := dc.user.User
+
 	if password != nil {
 		hashed, err := bcrypt.GenerateFromPassword([]byte(*password), bcrypt.DefaultCost)
 		if err != nil {
 			return fmt.Errorf("failed to hash password: %v", err)
 		}
-		if err := dc.user.updatePassword(string(hashed)); err != nil {
+		record.Password = string(hashed)
-			return err
-		}
 	}
 	if realname != nil {
-		if err := dc.user.updateRealname(*realname); err != nil {
+		record.Realname = *realname
-			return err
 	}
+
+	if err := dc.user.updateUser(&record); err != nil {
+		return err
 	}
 
 	sendServicePRIVMSG(dc, fmt.Sprintf("updated user %q", dc.user.Username))

user.go

@@ -856,17 +856,18 @@ func (u *user) deleteNetwork(id int64) error {
 	return nil
 }
 
-func (u *user) updatePassword(hashed string) error {
+func (u *user) updateUser(record *User) error {
-	u.User.Password = hashed
+	if u.ID != record.ID {
-	return u.srv.db.StoreUser(&u.User)
+		panic("ID mismatch when updating user")
-}
-
-func (u *user) updateRealname(realname string) error {
-	u.User.Realname = realname
-	if err := u.srv.db.StoreUser(&u.User); err != nil {
-		return fmt.Errorf("failed to update user %q: %v", u.Username, err)
 	}
 
+	realnameUpdated := u.Realname != record.Realname
+	if err := u.srv.db.StoreUser(record); err != nil {
+		return fmt.Errorf("failed to update user %q: %v", u.Username, err)
+	}
+	u.User = *record
+
+	if realnameUpdated {
 		// Re-connect to networks which use the default realname
 		var needUpdate []Network
 		u.forEachNetwork(func(net *network) {
@@ -881,8 +882,12 @@ func (u *user) updateRealname(realname string) error {
 				netErr = err
 			}
 		}
-
+		if netErr != nil {
 			return netErr
+		}
+	}
+
+	return nil
 }
 
 func (u *user) stop() {