Attempt to fix incorrect federation of default instance avatars

lib/pleroma/user.ex

@@ -90,6 +90,14 @@ def avatar_url(user) do
     end
   end
 
+  # Do not return instance default avatar for federation
+  def avatar_url_ap(user) do
+    case user.avatar do
+      %{"url" => [%{"href" => href} | _]} -> href
+      _ -> nil
+    end
+  end
+
   def banner_url(user) do
     case user.info.banner do
       %{"url" => [%{"href" => href} | _]} -> href

lib/pleroma/web/activity_pub/utils.ex

@@ -230,6 +230,21 @@ def update_object_in_activities(%{data: %{"id" => id}} = object) do
     end)
   end
 
+  # Only federate user icon if not nil
+  # Prevents federating instance default avatars
+  def maybe_make_icon(user) do
+    if User.avatar_url_ap(user) do
+      %{
+        "icon" => %{
+          "type" => "Image",
+          "url" => User.avatar_url_ap(user)
+        }
+      }
+    else
+      []
+    end
+  end
+
   #### Like-related helpers
 
   @doc """

lib/pleroma/web/activity_pub/views/user_view.ex

@@ -87,16 +87,13 @@ def render("user.json", %{user: user}) do
         "publicKeyPem" => public_key
       },
       "endpoints" => endpoints,
-      "icon" => %{
-        "type" => "Image",
-        "url" => User.avatar_url(user)
-      },
       "image" => %{
         "type" => "Image",
         "url" => User.banner_url(user)
       },
       "tag" => user.info.source_data["tag"] || []
     }
+    |> Map.merge(Utils.maybe_make_icon(user))
     |> Map.merge(Utils.make_json_ld_header())
   end