Keep incoming Link tag

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

@@ -9,15 +9,20 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.TagValidator do
 
   import Ecto.Changeset
 
+  require Pleroma.Constants
+
   @primary_key false
   embedded_schema do
     # Common
     field(:type, :string)
     field(:name, :string)
 
-    # Mention, Hashtag
+    # Mention, Hashtag, Link
     field(:href, ObjectValidators.Uri)
 
+    # Link
+    field(:mediaType, :string)
+
     # Emoji
     embeds_one :icon, IconObjectValidator, primary_key: false do
       field(:type, :string)
@@ -68,6 +73,13 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.TagValidator do
     |> validate_required([:type, :name, :icon])
   end
 
+  def changeset(struct, %{"type" => "Link"} = data) do
+    struct
+    |> cast(data, [:type, :name, :mediaType, :href])
+    |> validate_inclusion(:mediaType, Pleroma.Constants.activity_json_mime_types())
+    |> validate_required([:type, :href, :mediaType])
+  end
+
   def changeset(struct, %{"type" => _} = data) do
     struct
     |> cast(data, [])

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

@@ -157,5 +157,12 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.ArticleNotePageValidatorTest
 
     assert cng.valid?
     assert cng.changes.quoteUrl == "https://server.example/objects/123"
+
+    assert Enum.at(cng.changes.tag, 0).changes == %{
+             type: "Link",
+             mediaType: "application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\"",
+             href: "https://server.example/objects/123",
+             name: "RE: https://server.example/objects/123"
+           }
   end
 end