Copy emoji in the subject from parent post

Sometimes people put emoji in the subject, which results in the subject
looking broken if someone replies to it from a server that does not
have the said emoji under the same shortcode. This patch solves the problem
by extending the emoji set available in the summary to that of the parent
post.

4 files changed, 111 insertions, 0 deletions

diff --git a/lib/pleroma/web/common_api/activity_draft.ex b/lib/pleroma/web/common_api/activity_draft.ex
index 8668b600e..80a9fa7bb 100644
--- a/lib/pleroma/web/common_api/activity_draft.ex
+++ b/lib/pleroma/web/common_api/activity_draft.ex
@@ -5,6 +5,7 @@
 defmodule Pleroma.Web.CommonAPI.ActivityDraft do
   alias Pleroma.Activity
   alias Pleroma.Conversation.Participation
+  alias Pleroma.Object
   alias Pleroma.Web.CommonAPI
   alias Pleroma.Web.CommonAPI.Utils
 
@@ -186,6 +187,32 @@ defmodule Pleroma.Web.CommonAPI.ActivityDraft do
   defp object(draft) do
     emoji = Map.merge(Pleroma.Emoji.Formatter.get_emoji_map(draft.full_payload), draft.emoji)
 
+    # Sometimes people create posts with subject containing emoji,
+    # since subjects are usually copied this will result in a broken
+    # subject when someone replies from an instance that does not have
+    # the emoji or has it under different shortcode. This is an attempt
+    # to mitigate this by copying emoji from inReplyTo if they are present
+    # in the subject.
+    summary_emoji =
+      with %Activity{} <- draft.in_reply_to,
+           %Object{data: %{"tag" => [_ | _] = tag}} <- Object.normalize(draft.in_reply_to) do
+        Enum.reduce(tag, %{}, fn
+          %{"type" => "Emoji", "name" => name, "icon" => %{"url" => url}}, acc ->
+            if String.contains?(draft.summary, name) do
+              Map.put(acc, name, url)
+            else
+              acc
+            end
+
+          _, acc ->
+            acc
+        end)
+      else
+        _ -> %{}
+      end
+
+    emoji = Map.merge(emoji, summary_emoji)
+
     object =
       Utils.make_note_data(draft)
       |> Map.put("emoji", emoji)
diff --git a/test/fixtures/tesla_mock/emoji-in-summary.json b/test/fixtures/tesla_mock/emoji-in-summary.json
new file mode 100644
index 000000000..f77c6e2e8
--- /dev/null
+++ b/test/fixtures/tesla_mock/emoji-in-summary.json
@@ -0,0 +1,49 @@
+{
+  "@context": [
+    "https://www.w3.org/ns/activitystreams",
+    "https://patch.cx/schemas/litepub-0.1.jsonld",
+    {
+      "@language": "und"
+    }
+  ],
+  "actor": "https://patch.cx/users/rin",
+  "attachment": [],
+  "attributedTo": "https://patch.cx/users/rin",
+  "cc": [
+    "https://patch.cx/users/rin/followers"
+  ],
+  "content": ":joker_disapprove: <br><br>just grabbing a test fixture, nevermind me",
+  "context": "https://patch.cx/contexts/2c3ce4b4-18b1-4b1a-8965-3932027b5326",
+  "conversation": "https://patch.cx/contexts/2c3ce4b4-18b1-4b1a-8965-3932027b5326",
+  "id": "https://patch.cx/objects/a399c28e-c821-4820-bc3e-4afeb044c16f",
+  "published": "2021-03-22T16:54:46.461939Z",
+  "sensitive": null,
+  "source": ":joker_disapprove: \r\n\r\njust grabbing a test fixture, nevermind me",
+  "summary": ":joker_smile: ",
+  "tag": [
+    {
+      "icon": {
+        "type": "Image",
+        "url": "https://patch.cx/emoji/custom/joker_disapprove.png"
+      },
+      "id": "https://patch.cx/emoji/custom/joker_disapprove.png",
+      "name": ":joker_disapprove:",
+      "type": "Emoji",
+      "updated": "1970-01-01T00:00:00Z"
+    },
+    {
+      "icon": {
+        "type": "Image",
+        "url": "https://patch.cx/emoji/custom/joker_smile.png"
+      },
+      "id": "https://patch.cx/emoji/custom/joker_smile.png",
+      "name": ":joker_smile:",
+      "type": "Emoji",
+      "updated": "1970-01-01T00:00:00Z"
+    }
+  ],
+  "to": [
+    "https://www.w3.org/ns/activitystreams#Public"
+  ],
+  "type": "Note"
+}
diff --git a/test/pleroma/web/common_api_test.exs b/test/pleroma/web/common_api_test.exs
index 9d005697c..6619f8fc8 100644
--- a/test/pleroma/web/common_api_test.exs
+++ b/test/pleroma/web/common_api_test.exs
@@ -25,6 +25,11 @@ defmodule Pleroma.Web.CommonAPITest do
 
   require Pleroma.Constants
 
+  setup_all do
+    Tesla.Mock.mock_global(fn env -> apply(HttpRequestMock, :request, [env]) end)
+    :ok
+  end
+
   setup do: clear_config([:instance, :safe_dm_mentions])
   setup do: clear_config([:instance, :limit])
   setup do: clear_config([:instance, :max_pinned_statuses])
@@ -517,6 +522,27 @@ defmodule Pleroma.Web.CommonAPITest do
       assert url == "#{Pleroma.Web.base_url()}/emoji/blank.png"
     end
 
+    test "it copies emoji from the subject of the parent post" do
+      %Object{} =
+        object =
+        Object.normalize("https://patch.cx/objects/a399c28e-c821-4820-bc3e-4afeb044c16f",
+          fetch: true
+        )
+
+      activity = Activity.get_create_by_object_ap_id(object.data["id"])
+      user = insert(:user)
+
+      {:ok, reply_activity} =
+        CommonAPI.post(user, %{
+          in_reply_to_id: activity.id,
+          status: ":joker_disapprove:",
+          spoiler_text: ":joker_smile:"
+        })
+
+      assert Object.normalize(reply_activity).data["emoji"][":joker_smile:"]
+      refute Object.normalize(reply_activity).data["emoji"][":joker_disapprove:"]
+    end
+
     test "deactivated users can't post" do
       user = insert(:user, is_active: false)
       assert {:error, _} = CommonAPI.post(user, %{status: "ye"})
diff --git a/test/support/http_request_mock.ex b/test/support/http_request_mock.ex
index 1e98020f0..eb692fab5 100644
--- a/test/support/http_request_mock.ex
+++ b/test/support/http_request_mock.ex
@@ -1278,6 +1278,15 @@ defmodule HttpRequestMock do
      }}
   end
 
+  def get("https://patch.cx/objects/a399c28e-c821-4820-bc3e-4afeb044c16f", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/emoji-in-summary.json"),
+       headers: activitypub_object_headers()
+     }}
+  end
+
   def get(url, query, body, headers) do
     {:error,
      "Mock response not implemented for GET #{inspect(url)}, #{query}, #{inspect(body)}, #{