CreateGenericValidator: fix reply context fixing

Incoming Pleroma replies to a Misskey thread were rejected due to a
broken context fix, which caused them to not be visible until a
non-Pleroma user interacted with the replies.

This fix properly sets the post-fix object context to its parent Create
activity as well, if it was changed.

test/pleroma/web/activity_pub/object_validators/create_generic_validator_test.exs

@@ -23,10 +23,10 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CreateGenericValidatorTest do
     {:ok, object_data} = ObjectValidator.cast_and_apply(note_activity["object"])
     meta = [object_data: ObjectValidator.stringify_keys(object_data)]
 
-    %{valid?: true} = CreateGenericValidator.cast_and_validate(note_activity, meta)
+    assert %{valid?: true} = CreateGenericValidator.cast_and_validate(note_activity, meta)
   end
 
-  test "a Create/Note with mismatched context is invalid" do
+  test "a Create/Note with mismatched context uses the Note's context" do
     user = insert(:user)
 
     note = %{
@@ -54,6 +54,9 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CreateGenericValidatorTest do
     {:ok, object_data} = ObjectValidator.cast_and_apply(note_activity["object"])
     meta = [object_data: ObjectValidator.stringify_keys(object_data)]
 
-    %{valid?: false} = CreateGenericValidator.cast_and_validate(note_activity, meta)
+    validated = CreateGenericValidator.cast_and_validate(note_activity, meta)
+
+    assert validated.valid?
+    assert {:context, note["context"]} in validated.changes
   end
 end

test/pleroma/web/activity_pub/transmogrifier_test.exs

@@ -108,15 +108,20 @@ defmodule Pleroma.Web.ActivityPub.TransmogrifierTest do
       assert activity.data["type"] == "Move"
     end
 
-    test "a reply with mismatched context is rejected" do
-      insert(:user, ap_id: "https://macgirvin.com/channel/mike")
+    test "it fixes both the Create and object contexts in a reply" do
+      insert(:user, ap_id: "https://mk.absturztau.be/users/8ozbzjs3o8")
+      insert(:user, ap_id: "https://p.helene.moe/users/helene")
 
-      note_activity =
-        "test/fixtures/roadhouse-create-activity.json"
+      create_activity =
+        "test/fixtures/create-pleroma-reply-to-misskey-thread.json"
         |> File.read!()
         |> Jason.decode!()
 
-      assert {:error, _} = Transmogrifier.handle_incoming(note_activity)
+      assert {:ok, %Activity{} = activity} = Transmogrifier.handle_incoming(create_activity)
+
+      object = Object.normalize(activity, fetch: false)
+
+      assert activity.data["context"] == object.data["context"]
     end
   end