TagValidator: Drop unrecognized tags

lib/pleroma/web/activity_pub/object_validators/tag_validator.ex

@@ -68,8 +68,11 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.TagValidator do
     |> validate_required([:type, :name, :icon])
   end
 
-  # Fallback
-  def changeset(struct, data), do: cast(struct, data, [:type, :name])
+  def changeset(struct, %{"type" => _} = data) do
+    struct
+    |> cast(data, [])
+    |> Map.put(:action, :ignore)
+  end
 
   def icon_changeset(struct, data) do
     struct

test/fixtures/fep-e232.json

@@ -9,6 +9,11 @@
     "content": "<p>test <a href=\"https://example.org/objects/9\">https://example.org/objects/9</a></p>",
     "published": "2022-10-01T21:30:05.211215Z",
     "tag": [
+      {
+        "name": "@bob@example.net",
+        "type": "Mention",
+        "href": "https://example.net/users/bob"
+      },
       {
         "name": "https://example.org/objects/9",
         "type": "Link",

test/pleroma/web/activity_pub/transmogrifier_test.exs

@@ -124,8 +124,7 @@ defmodule Pleroma.Web.ActivityPub.TransmogrifierTest do
       assert activity.data["context"] == object.data["context"]
     end
 
-    # https://codeberg.org/fediverse/fep/src/branch/main/feps/fep-e232.md
-    test "it accepts FEP-e232 link tags" do
+    test "it drops link tags" do
       insert(:user, ap_id: "https://example.org/users/alice")
 
       message = File.read!("test/fixtures/fep-e232.json") |> Jason.decode!()
@@ -136,8 +135,7 @@ defmodule Pleroma.Web.ActivityPub.TransmogrifierTest do
       assert length(object.data["tag"]) == 1
 
       tag = object.data["tag"] |> List.first()
-      assert tag["type"] == "Link"
-      assert tag["name"] == "https://example.org/objects/9"
+      assert tag["type"] == "Mention"
     end
   end