[#2456] Added support for embed_relationships param, nailed down endpoints which should support it. Fixed :source_mutes relationships subset fetching.

lib/pleroma/user_relationship.ex

@@ -87,6 +87,22 @@ defmodule Pleroma.UserRelationship do
         source_to_target_rel_types \\ nil,
         target_to_source_rel_types \\ nil
       )
+
+  def dictionary(
+        _source_users,
+        _target_users,
+        [] = _source_to_target_rel_types,
+        [] = _target_to_source_rel_types
+      ) do
+    []
+  end
+
+  def dictionary(
+        source_users,
+        target_users,
+        source_to_target_rel_types,
+        target_to_source_rel_types
+      )
       when is_list(source_users) and is_list(target_users) do
     source_user_ids = User.binary_id(source_users)
     target_user_ids = User.binary_id(target_users)
@@ -138,11 +154,16 @@ defmodule Pleroma.UserRelationship do
 
   def view_relationships_option(%User{} = reading_user, actors, opts) do
     {source_to_target_rel_types, target_to_source_rel_types} =
-      if opts[:source_mutes_only] do
-        # This option is used for rendering statuses (FE needs `muted` flag for each one anyways)
-        {[:mute], []}
-      else
-        {[:block, :mute, :notification_mute, :reblog_mute], [:block, :inverse_subscription]}
+      case opts[:subset] do
+        :source_mutes ->
+          # Used for statuses rendering (FE needs `muted` flag for each status when statuses load)
+          {[:mute], []}
+
+        nil ->
+          {[:block, :mute, :notification_mute, :reblog_mute], [:block, :inverse_subscription]}
+
+        unknown ->
+          raise "Unsupported :subset option value: #{inspect(unknown)}"
       end
 
     user_relationships =
@@ -153,7 +174,17 @@ defmodule Pleroma.UserRelationship do
         target_to_source_rel_types
       )
 
-    following_relationships = FollowingRelationship.all_between_user_sets([reading_user], actors)
+    following_relationships =
+      case opts[:subset] do
+        :source_mutes ->
+          []
+
+        nil ->
+          FollowingRelationship.all_between_user_sets([reading_user], actors)
+
+        unknown ->
+          raise "Unsupported :subset option value: #{inspect(unknown)}"
+      end
 
     %{user_relationships: user_relationships, following_relationships: following_relationships}
   end