Assure that common_name is assoc'd on a User correctly (#34056)

src/metabase/models/user.clj

@@ -170,13 +170,17 @@
       email       (update :email u/lower-case-en))))
 
 (defn add-common-name
-  "Add a `:common_name` key to `user` by combining their first and last names, or using their email if names are `nil`."
+  "Conditionally add a `:common_name` key to `user` by combining their first and last names, or using their email if names are `nil`.
+  The key will only be added if `user` contains the required keys to derive it correctly."
   [{:keys [first_name last_name email], :as user}]
   (let [common-name (if (or first_name last_name)
                       (str/trim (str first_name " " last_name))
                       email)]
     (cond-> user
-      common-name (assoc :common_name common-name))))
+      (and (contains? user :first_name)
+           (contains? user :last_name)
+           common-name)
+      (assoc :common_name common-name))))
 
 (t2/define-after-select :model/User
   [user]

test/metabase/models/user_test.clj

@@ -534,3 +534,22 @@
       (t2.with-temp/with-temp [User {user-id :id} {}]
         (mw.session/with-current-user user-id
           (is (= "v0.47.1" (setting/get :last-acknowledged-version))))))))
+
+(deftest common-name-test
+  (testing "common_name should be present depending on what is selected"
+    (mt/with-temp [User user {:first_name "John"
+                              :last_name  "Smith"
+                              :email      "john.smith@gmail.com"}]
+      (is (= "John Smith"
+             (:common_name (t2/select-one [User :first_name :last_name] (:id user)))))
+      (is (= "John Smith"
+             (:common_name (t2/select-one User (:id user)))))
+      (is (nil? (:common_name (t2/select-one [User :first_name :email] (:id user)))))
+      (is (nil? (:common_name (t2/select-one [User :email] (:id user)))))))
+  (testing "common_name should be present if first_name and last_name are selected but nil and email is also selected"
+    (mt/with-temp [User user {:first_name nil
+                              :last_name  nil
+                              :email      "john.smith@gmail.com"}]
+      (is (= "john.smith@gmail.com"
+             (:common_name (t2/select-one [User :email :first_name :last_name] (:id user)))))
+      (is (nil? (:common_name (t2/select-one [User :first_name :last_name] (:id user))))))))