lib/pleroma/user.ex

@@ -2307,6 +2307,19 @@ def add_alias(user, new_alias_user) do
     end
   end
 
+  def delete_alias(user, alias_user) do
+    current_aliases = user.also_known_as || []
+    alias_ap_id = alias_user.ap_id
+
+    if alias_ap_id in current_aliases do
+      user
+      |> cast(%{also_known_as: current_aliases -- [alias_ap_id]}, [:also_known_as])
+      |> update_and_set_cache()
+    else
+      {:error, :no_such_alias}
+    end
+  end
+
   # Internal function; public one is `deactivate/2`
   defp set_activation_status(user, status) do
     user

lib/pleroma/web/api_spec/operations/twitter_util_operation.ex

@@ -312,6 +312,46 @@ defp add_alias_request do
     }
   end
 
+  def delete_alias_operation do
+    %Operation{
+      tags: ["Account credentials"],
+      summary: "Delete an alias from this account",
+      security: [%{"oAuth" => ["write:accounts"]}],
+      operationId: "UtilController.delete_alias",
+      requestBody: request_body("Parameters", delete_alias_request(), required: true),
+      responses: %{
+        200 =>
+          Operation.response("Success", "application/json", %Schema{
+            type: :object,
+            properties: %{
+              status: %Schema{
+                type: :string,
+                example: "success"
+              }
+            }
+          }),
+        400 => Operation.response("Error", "application/json", ApiError),
+        403 => Operation.response("Error", "application/json", ApiError),
+        404 => Operation.response("Error", "application/json", ApiError)
+      }
+    }
+  end
+
+  defp delete_alias_request do
+    %Schema{
+      title: "DeleteAliasRequest",
+      description: "PUT body for deleting aliases",
+      type: :object,
+      required: [:alias],
+      properties: %{
+        alias: %Schema{
+          type: :string,
+          description: "The nickname of the account to delete from aliases"
+        }
+      }
+    }
+  end
+
   def healthcheck_operation do
     %Operation{
       tags: ["Accounts"],

lib/pleroma/web/router.ex

@@ -353,6 +353,7 @@ defmodule Pleroma.Web.Router do
 
     put("/aliases", UtilController, :add_alias)
     get("/aliases", UtilController, :list_aliases)
+    delete("/aliases", UtilController, :delete_alias)
   end
 
   scope "/api/pleroma", Pleroma.Web.PleromaAPI do

lib/pleroma/web/twitter_api/controllers/util_controller.ex

@@ -29,7 +29,8 @@ defmodule Pleroma.Web.TwitterAPI.UtilController do
            :update_notificaton_settings,
            :disable_account,
            :move_account,
-           :add_alias
+           :add_alias,
+           :delete_alias
          ]
   )
 
@@ -198,8 +199,24 @@ def add_alias(%{assigns: %{user: user}, body_params: body_params} = conn, _) do
     end
   end
 
+  def delete_alias(%{assigns: %{user: user}, body_params: body_params} = conn, _) do
+    with {:ok, alias_user} <- find_user_by_nickname(body_params.alias),
+         {:ok, _user} <- user |> User.delete_alias(alias_user) do
+      json(conn, %{status: "success"})
+    else
+      {:error, :no_such_alias} ->
+        conn
+        |> put_status(404)
+        |> json(%{error: "Account has no such alias."})
+
+      {:error, error} ->
+        json(conn, %{error: error})
+    end
+  end
+
   def list_aliases(%{assigns: %{user: user}} = conn, %{}) do
-    alias_nicks = user
+    alias_nicks =
+      user
       |> User.alias_users()
       |> Enum.map(&User.full_nickname/1)
 

test/pleroma/user_test.exs

@@ -2573,4 +2573,28 @@ test "should get aliases for a user" do
       assert alias_user.ap_id == user.ap_id
     end
   end
+
+  describe "delete_alias/2" do
+    test "should delete existing alias" do
+      user = insert(:user)
+      user2 = insert(:user, also_known_as: [user.ap_id])
+
+      assert {:ok, user_updated} = user2 |> User.delete_alias(user)
+
+      assert user_updated.also_known_as == []
+    end
+
+    test "should report error on non-existing alias" do
+      user = insert(:user)
+      user2 = insert(:user)
+      user3 = insert(:user, also_known_as: [user.ap_id])
+
+      assert {:error, :no_such_alias} = user3 |> User.delete_alias(user2)
+
+      user3_updated = User.get_cached_by_ap_id(user3.ap_id)
+
+      assert user3_updated.also_known_as |> length() == 1
+      assert user.ap_id in user3_updated.also_known_as
+    end
+  end
 end

test/pleroma/web/twitter_api/util_controller_test.exs

@@ -669,9 +669,10 @@ test "without permissions", %{conn: conn} do
     test "with permissions", %{
       conn: conn
     } do
-      assert %{"aliases" => []} = conn
-        |> get("/api/pleroma/aliases")
-        |> json_response_and_validate_schema(200)
+      assert %{"aliases" => []} =
+               conn
+               |> get("/api/pleroma/aliases")
+               |> json_response_and_validate_schema(200)
     end
 
     test "with permissions and aliases", %{} do
@@ -682,9 +683,11 @@ test "with permissions and aliases", %{} do
 
       %{user: _user, conn: conn} = oauth_access(["read:accounts"], user: user)
 
-      assert %{"aliases" => aliases} = conn
-        |> get("/api/pleroma/aliases")
-        |> json_response_and_validate_schema(200)
+      assert %{"aliases" => aliases} =
+               conn
+               |> get("/api/pleroma/aliases")
+               |> json_response_and_validate_schema(200)
+
       assert aliases == [user2 |> User.full_nickname()]
     end
   end
@@ -730,4 +733,62 @@ test "with permissions, with alias param", %{
              }
     end
   end
+
+  describe "DELETE /api/pleroma/aliases" do
+    setup do
+      alias_user = insert(:user)
+      non_alias_user = insert(:user)
+      user = insert(:user, also_known_as: [alias_user.ap_id])
+
+      oauth_access(["write:accounts"], user: user)
+      |> Map.put(:alias_user, alias_user)
+      |> Map.put(:non_alias_user, non_alias_user)
+    end
+
+    test "without permissions", %{conn: conn} do
+      conn =
+        conn
+        |> assign(:token, nil)
+        |> put_req_header("content-type", "application/json")
+        |> delete("/api/pleroma/aliases", %{alias: "none"})
+
+      assert json_response_and_validate_schema(conn, 403) == %{
+               "error" => "Insufficient permissions: write:accounts."
+             }
+    end
+
+    test "with permissions, no alias param", %{conn: conn} do
+      conn =
+        conn
+        |> put_req_header("content-type", "application/json")
+        |> delete("/api/pleroma/aliases", %{})
+
+      assert %{"error" => "Missing field: alias."} = json_response_and_validate_schema(conn, 400)
+    end
+
+    test "with permissions, account does not have such alias", %{
+      conn: conn,
+      non_alias_user: non_alias_user
+    } do
+      conn =
+        conn
+        |> put_req_header("content-type", "application/json")
+        |> delete("/api/pleroma/aliases", %{alias: non_alias_user |> User.full_nickname()})
+
+      assert %{"error" => "Account has no such alias."} =
+               json_response_and_validate_schema(conn, 404)
+    end
+
+    test "with permissions, account does have such alias", %{
+      conn: conn,
+      alias_user: alias_user
+    } do
+      conn =
+        conn
+        |> put_req_header("content-type", "application/json")
+        |> delete("/api/pleroma/aliases", %{alias: alias_user |> User.full_nickname()})
+
+      assert %{"status" => "success"} = json_response_and_validate_schema(conn, 200)
+    end
+  end
 end