Make sure actor usernames are unique

Closes #72

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/mobilizon/actors/actor.ex

@@ -50,7 +50,7 @@ defmodule Mobilizon.Actors.Actor do
     field(:suspended, :boolean, default: false)
     field(:avatar_url, :string)
     field(:banner_url, :string)
-    # field(:openness, Mobilizon.Actors.ActorOpennesssEnum, default: :moderated)
+    # field(:openness, Mobilizon.Actors.ActorOpennessEnum, default: :moderated)
     has_many(:followers, Follower, foreign_key: :target_actor_id)
     has_many(:followings, Follower, foreign_key: :actor_id)
     has_many(:organized_events, Event, foreign_key: :organizer_actor_id)
@@ -83,6 +83,7 @@ defmodule Mobilizon.Actors.Actor do
       :user_id
     ])
     |> build_urls()
+    |> unique_username_validator()
     |> validate_required([:preferred_username, :keys, :suspended, :url])
     |> unique_constraint(:preferred_username, name: :actors_preferred_username_domain_type_index)
     |> unique_constraint(:url, name: :actors_url_index)
@@ -141,6 +142,8 @@ defmodule Mobilizon.Actors.Actor do
         :preferred_username,
         :keys
       ])
+      # Needed because following constraint can't work for domain null values (local)
+      |> unique_username_validator()
       |> unique_constraint(:preferred_username, name: :actors_preferred_username_domain_type_index)
       |> unique_constraint(:url, name: :actors_url_index)
       |> validate_length(:summary, max: 5000)
@@ -171,6 +174,7 @@ defmodule Mobilizon.Actors.Actor do
     |> put_change(:domain, nil)
     |> put_change(:keys, Actors.create_keys())
     |> put_change(:type, :Group)
+    |> unique_username_validator()
     |> validate_required([:url, :outbox_url, :inbox_url, :type, :preferred_username])
     |> unique_constraint(:preferred_username, name: :actors_preferred_username_domain_type_index)
     |> unique_constraint(:url, name: :actors_url_index)
@@ -179,16 +183,22 @@ defmodule Mobilizon.Actors.Actor do
     |> put_change(:local, true)
   end
 
-  def unique_username_validator(
-        %Ecto.Changeset{changes: %{preferred_username: username}} = changeset
+  defp unique_username_validator(
+         %Ecto.Changeset{changes: %{preferred_username: username} = changes} = changeset
        ) do
-    if Actors.get_local_actor_by_name(username) do
+    with nil <- Map.get(changes, :domain, nil),
+         %Actor{preferred_username: _username} <- Actors.get_local_actor_by_name(username) do
       changeset |> add_error(:preferred_username, "Username is already taken")
     else
-      changeset
+      _ -> changeset
     end
   end
 
+  # When we don't even have any preferred_username, don't even try validating preferred_username
+  defp unique_username_validator(changeset) do
+    changeset
+  end
+
   @spec build_urls(Ecto.Changeset.t(), atom()) :: Ecto.Changeset.t()
   defp build_urls(changeset, type \\ :Person)
 

test/mobilizon/actors/actors_test.exs

@@ -35,7 +35,7 @@ defmodule Mobilizon.ActorsTest do
       suspended: nil,
       uri: nil,
       url: nil,
-      preferred_username: nil
+      preferred_username: "never"
     }
 
     @remote_account_url "https://social.tcit.fr/users/tcit"
@@ -388,6 +388,22 @@ defmodule Mobilizon.ActorsTest do
       assert group.preferred_username == "some-title"
     end
 
+    test "create_group/1 with an existing profile username fails" do
+      _actor = insert(:actor, preferred_username: @valid_attrs.preferred_username)
+
+      assert {:error,
+              %Ecto.Changeset{errors: [preferred_username: {"Username is already taken", []}]}} =
+               Actors.create_group(@valid_attrs)
+    end
+
+    test "create_group/1 with an existing group username fails" do
+      assert {:ok, %Actor{} = group} = Actors.create_group(@valid_attrs)
+
+      assert {:error,
+              %Ecto.Changeset{errors: [preferred_username: {"Username is already taken", []}]}} =
+               Actors.create_group(@valid_attrs)
+    end
+
     test "create_group/1 with invalid data returns error changeset" do
       assert {:error, %Ecto.Changeset{}} = Actors.create_group(@invalid_attrs)
     end