4 files changed, 47 insertions, 13 deletions
diff --git a/model/user.go b/model/user.go
index f43fc2089..7563de8ae 100644
--- a/model/user.go
+++ b/model/user.go
@@ -186,13 +186,28 @@ func (u *User) SetDefaultNotifications() {
 	u.NotifyProps["desktop"] = USER_NOTIFY_ALL
 	u.NotifyProps["desktop_sound"] = "true"
 	u.NotifyProps["mention_keys"] = u.Username + ",@" + u.Username
-	u.NotifyProps["first_name"] = "false"
 	u.NotifyProps["all"] = "true"
 	u.NotifyProps["channel"] = "true"
-	splitName := strings.Split(u.Nickname, " ")
-	if len(splitName) > 0 && splitName[0] != "" {
+
+	if u.FirstName == "" {
+		u.NotifyProps["first_name"] = "false"
+	} else {
 		u.NotifyProps["first_name"] = "true"
-		u.NotifyProps["mention_keys"] += "," + splitName[0]
+	}
+}
+
+func (user *User) UpdateMentionKeysFromUsername(oldUsername string) {
+	nonUsernameKeys := []string{}
+	splitKeys := strings.Split(user.NotifyProps["mention_keys"], ",")
+	for _, key := range splitKeys {
+		if key != oldUsername && key != "@"+oldUsername {
+			nonUsernameKeys = append(nonUsernameKeys, key)
+		}
+	}
+
+	user.NotifyProps["mention_keys"] = user.Username + ",@" + user.Username
+	if len(nonUsernameKeys) > 0 {
+		user.NotifyProps["mention_keys"] += "," + strings.Join(nonUsernameKeys, ",")
 	}
 }
 
diff --git a/model/user_test.go b/model/user_test.go
index 286c92a66..c6f7dfecc 100644
--- a/model/user_test.go
+++ b/model/user_test.go
@@ -41,6 +41,33 @@ func TestUserPreUpdate(t *testing.T) {
 	user.PreUpdate()
 }
 
+func TestUserUpdateMentionKeysFromUsername(t *testing.T) {
+	user := User{Username: "user"}
+	user.SetDefaultNotifications()
+
+	if user.NotifyProps["mention_keys"] != "user,@user" {
+		t.Fatal("default mention keys are invalid: %v", user.NotifyProps["mention_keys"])
+	}
+
+	user.Username = "person"
+	user.UpdateMentionKeysFromUsername("user")
+	if user.NotifyProps["mention_keys"] != "person,@person" {
+		t.Fatal("mention keys are invalid after changing username: %v", user.NotifyProps["mention_keys"])
+	}
+
+	user.NotifyProps["mention_keys"] += ",mention"
+	user.UpdateMentionKeysFromUsername("person")
+	if user.NotifyProps["mention_keys"] != "person,@person,mention" {
+		t.Fatal("mention keys are invalid after adding extra mention keyword: %v", user.NotifyProps["mention_keys"])
+	}
+
+	user.Username = "user"
+	user.UpdateMentionKeysFromUsername("person")
+	if user.NotifyProps["mention_keys"] != "user,@user,mention" {
+		t.Fatal("mention keys are invalid after changing username with extra mention keyword: %v", user.NotifyProps["mention_keys"])
+	}
+}
+
 func TestUserIsValid(t *testing.T) {
 	user := User{}
 
diff --git a/store/sql_user_store.go b/store/sql_user_store.go
index ea83458e9..636400ce9 100644
--- a/store/sql_user_store.go
+++ b/store/sql_user_store.go
@@ -141,14 +141,7 @@ func (us SqlUserStore) Update(user *model.User, allowActiveUpdate bool) StoreCha
 			}
 
 			if user.Username != oldUser.Username {
-				nonUsernameKeys := []string{}
-				splitKeys := strings.Split(user.NotifyProps["mention_keys"], ",")
-				for _, key := range splitKeys {
-					if key != oldUser.Username && key != "@"+oldUser.Username {
-						nonUsernameKeys = append(nonUsernameKeys, key)
-					}
-				}
-				user.NotifyProps["mention_keys"] = strings.Join(nonUsernameKeys, ",") + "," + user.Username + ",@" + user.Username
+				user.UpdateMentionKeysFromUsername(oldUser.Username)
 			}
 
 			if count, err := us.GetMaster().Update(user); err != nil {
diff --git a/webapp/utils/text_formatting.jsx b/webapp/utils/text_formatting.jsx
index 3aa82ccdc..88dc412ca 100644
--- a/webapp/utils/text_formatting.jsx
+++ b/webapp/utils/text_formatting.jsx
@@ -214,7 +214,6 @@ function highlightCurrentMentions(text, tokens) {
     }
 
     for (const mention of UserStore.getCurrentMentionKeys()) {
-        // occasionally we get an empty mention which matches a bunch of empty strings
         if (!mention) {
             continue;
         }