From 28ff828caaada329283a37feb3940b543ef260a3 Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 28 Feb 2023 10:40:24 -0500
Subject: [PATCH 01/11] Add emoji policy to remove emojis matching certain urls

https://git.pleroma.social/pleroma/pleroma/-/issues/2775
---
 config/config.exs                             |   6 +
 lib/pleroma/web/activity_pub/emoji_policy.ex  | 158 ++++++++++++++++++
 .../activity_pub/mrf/emoji_policy_test.exs    | 123 ++++++++++++++
 3 files changed, 287 insertions(+)
 create mode 100644 lib/pleroma/web/activity_pub/emoji_policy.ex
 create mode 100644 test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs

diff --git a/config/config.exs b/config/config.exs
index a92ab574b..ebcbf8b49 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -408,6 +408,12 @@
   federated_timeline_removal: [],
   replace: []
 
+config :pleroma, :mrf_emoji,
+  remove_url: [],
+  remove_shortcode: [],
+  federated_timeline_removal_url: [],
+  federated_timeline_removal_shortcode: []
+
 config :pleroma, :mrf_hashtag,
   sensitive: ["nsfw"],
   reject: [],
diff --git a/lib/pleroma/web/activity_pub/emoji_policy.ex b/lib/pleroma/web/activity_pub/emoji_policy.ex
new file mode 100644
index 000000000..747e720b6
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/emoji_policy.ex
@@ -0,0 +1,158 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicy do
+  require Pleroma.Constants
+
+  @moduledoc "Reject or force-unlisted emojis with certain URLs or names"
+
+  @behaviour Pleroma.Web.ActivityPub.MRF.Policy
+
+  defp config_remove_url do
+    Pleroma.Config.get([:mrf_emoji, :remove_url], [])
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def filter(%{"type" => type, "object" => %{} = object} = message)
+      when type in ["Create", "Update"] do
+    with object <- process_remove(object, :url, config_remove_url()) do
+      {:ok, Map.put(message, "object", object)}
+    end
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def filter(%{"type" => type} = object) when type in Pleroma.Constants.actor_types() do
+    with object <- process_remove(object, :url, config_remove_url()) do
+      {:ok, object}
+    end
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def filter(message) do
+    {:ok, message}
+  end
+
+  defp match_string?(string, pattern) when is_binary(pattern) do
+    string == pattern
+  end
+
+  defp match_string?(string, %Regex{} = pattern) do
+    String.match?(string, pattern)
+  end
+
+  defp match_any?(string, patterns) do
+    Enum.any?(patterns, &match_string?(string, &1))
+  end
+
+  defp process_remove(object, :url, patterns) do
+    processed_tag =
+      Enum.filter(
+        object["tag"],
+        fn
+          %{"type" => "Emoji", "icon" => %{"url" => url}} when is_binary(url) ->
+            not match_any?(url, patterns)
+
+          _ ->
+            true
+        end
+      )
+
+    processed_emoji =
+      if object["emoji"] do
+        object["emoji"]
+        |> Enum.reduce(%{}, fn {name, url}, acc ->
+          if not match_any?(url, patterns) do
+            Map.put(acc, name, url)
+          else
+            acc
+          end
+        end)
+      else
+        nil
+      end
+
+    if processed_emoji do
+      object
+      |> Map.put("tag", processed_tag)
+      |> Map.put("emoji", processed_emoji)
+    else
+      object
+      |> Map.put("tag", processed_tag)
+    end
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def describe do
+    # This horror is needed to convert regex sigils to strings
+    mrf_emoji =
+      Pleroma.Config.get(:mrf_emoji, [])
+      |> Enum.map(fn {key, value} ->
+        {key,
+         Enum.map(value, fn
+           pattern ->
+             if not is_binary(pattern) do
+               inspect(pattern)
+             else
+               pattern
+             end
+         end)}
+      end)
+      |> Enum.into(%{})
+
+    {:ok, %{mrf_emoji: mrf_emoji}}
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def config_description do
+    %{
+      key: :mrf_emoji,
+      related_policy: "Pleroma.Web.ActivityPub.MRF.EmojiPolicy",
+      label: "MRF Emoji",
+      description:
+        "Reject or force-unlisted emojis whose URLs or names match a keyword or [Regex](https://hexdocs.pm/elixir/Regex.html).",
+      children: [
+        %{
+          key: :remove_url,
+          type: {:list, :string},
+          description: """
+            A list of patterns which result in emoji whose URL matches being removed from the message. This will apply to both statuses and user profiles.
+
+            Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
+          """,
+          suggestions: ["foo", ~r/foo/iu]
+        },
+        %{
+          key: :remove_shortcode,
+          type: {:list, :string},
+          description: """
+            A list of patterns which result in emoji whose shortcode matches being removed from the message. This will apply to both statuses and user profiles.
+
+            Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
+          """,
+          suggestions: ["foo", ~r/foo/iu]
+        },
+        %{
+          key: :federated_timeline_removal_url,
+          type: {:list, :string},
+          description: """
+            A list of patterns which result in message with emojis whose URLs match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses.
+
+            Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
+          """,
+          suggestions: ["foo", ~r/foo/iu]
+        },
+        %{
+          key: :federated_timeline_removal_shortcode,
+          type: {:list, :string},
+          description: """
+            A list of patterns which result in message with emojis whose shortcodes match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses.
+
+            Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
+          """,
+          suggestions: ["foo", ~r/foo/iu]
+        }
+      ]
+    }
+  end
+end
diff --git a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
new file mode 100644
index 000000000..fe1fb338e
--- /dev/null
+++ b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
@@ -0,0 +1,123 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicyTest do
+  use Pleroma.DataCase
+
+  alias Pleroma.Web.ActivityPub.MRF
+  alias Pleroma.Web.ActivityPub.MRF.EmojiPolicy
+
+  setup do: clear_config(:mrf_emoji)
+
+  setup do
+    clear_config([:mrf_emoji], %{
+      remove_url: [],
+      remove_shortcode: [],
+      federated_timeline_removal_url: [],
+      federated_timeline_removal_shortcode: []
+    })
+  end
+
+  @emoji_tags [
+    %{
+      "icon" => %{
+        "type" => "Image",
+        "url" => "https://example.org/emoji/biribiri/mikoto_smile2.png"
+      },
+      "id" => "https://example.org/emoji/biribiri/mikoto_smile2.png",
+      "name" => ":mikoto_smile2:",
+      "type" => "Emoji",
+      "updated" => "1970-01-01T00:00:00Z"
+    },
+    %{
+      "icon" => %{
+        "type" => "Image",
+        "url" => "https://example.org/emoji/biribiri/mikoto_smile3.png"
+      },
+      "id" => "https://example.org/emoji/biribiri/mikoto_smile3.png",
+      "name" => ":mikoto_smile3:",
+      "type" => "Emoji",
+      "updated" => "1970-01-01T00:00:00Z"
+    },
+    %{
+      "icon" => %{
+        "type" => "Image",
+        "url" => "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      },
+      "id" => "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png",
+      "name" => ":nekomimi_girl_emoji_007:",
+      "type" => "Emoji",
+      "updated" => "1970-01-01T00:00:00Z"
+    },
+    %{
+      "icon" => %{
+        "type" => "Image",
+        "url" => "https://example.org/test.png"
+      },
+      "id" => "https://example.org/test.png",
+      "name" => ":test:",
+      "type" => "Emoji",
+      "updated" => "1970-01-01T00:00:00Z"
+    }
+  ]
+
+  @misc_tags [%{"type" => "Placeholder"}]
+
+  @user_data %{
+    "type" => "Person",
+    "id" => "https://example.org/placeholder",
+    "name" => "lol",
+    "tag" => @emoji_tags ++ @misc_tags
+  }
+
+  @status_data %{
+    "type" => "Create",
+    "object" => %{
+      "type" => "Note",
+      "id" => "https://example.org/placeholder",
+      "content" => "lol",
+      "tag" => @emoji_tags ++ @misc_tags,
+      "emoji" => %{
+        "mikoto_smile2" => "https://example.org/emoji/biribiri/mikoto_smile2.png",
+        "mikoto_smile3" => "https://example.org/emoji/biribiri/mikoto_smile3.png",
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png",
+        "test" => "https://example.org/test.png"
+      }
+    }
+  }
+
+  describe "remove_url" do
+    setup do
+      clear_config([:mrf_emoji, :remove_url], [
+        "https://example.org/test.png",
+        ~r{/biribiri/mikoto_smile[23]\.png},
+        "nekomimi_girl_emoji"
+      ])
+
+      :ok
+    end
+
+    test "processes user" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @user_data)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      assert %{"tag" => ^expected_tags} = filtered
+    end
+
+    test "processes status" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{"object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}} = filtered
+    end
+  end
+end

From 80ce6482f6eb85f4c1d172811affc4a17d24985a Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 28 Feb 2023 10:51:56 -0500
Subject: [PATCH 02/11] EmojiPolicy: implement remove by shortcode

---
 lib/pleroma/web/activity_pub/emoji_policy.ex  | 48 ++++++++++++++++---
 .../activity_pub/mrf/emoji_policy_test.exs    | 33 +++++++++++++
 2 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/lib/pleroma/web/activity_pub/emoji_policy.ex b/lib/pleroma/web/activity_pub/emoji_policy.ex
index 747e720b6..346b64699 100644
--- a/lib/pleroma/web/activity_pub/emoji_policy.ex
+++ b/lib/pleroma/web/activity_pub/emoji_policy.ex
@@ -13,17 +13,23 @@ defp config_remove_url do
     Pleroma.Config.get([:mrf_emoji, :remove_url], [])
   end
 
+  defp config_remove_shortcode do
+    Pleroma.Config.get([:mrf_emoji, :remove_shortcode], [])
+  end
+
   @impl Pleroma.Web.ActivityPub.MRF.Policy
   def filter(%{"type" => type, "object" => %{} = object} = message)
       when type in ["Create", "Update"] do
-    with object <- process_remove(object, :url, config_remove_url()) do
+    with object <- process_remove(object, :url, config_remove_url()),
+         object <- process_remove(object, :shortcode, config_remove_shortcode()) do
       {:ok, Map.put(message, "object", object)}
     end
   end
 
   @impl Pleroma.Web.ActivityPub.MRF.Policy
   def filter(%{"type" => type} = object) when type in Pleroma.Constants.actor_types() do
-    with object <- process_remove(object, :url, config_remove_url()) do
+    with object <- process_remove(object, :url, config_remove_url()),
+         object <- process_remove(object, :shortcode, config_remove_shortcode()) do
       {:ok, object}
     end
   end
@@ -46,12 +52,42 @@ defp match_any?(string, patterns) do
   end
 
   defp process_remove(object, :url, patterns) do
+    process_remove_impl(
+      object,
+      fn
+        %{"icon" => %{"url" => url}} -> url
+        _ -> nil
+      end,
+      fn {_name, url} -> url end,
+      patterns
+    )
+  end
+
+  defp process_remove(object, :shortcode, patterns) do
+    process_remove_impl(
+      object,
+      fn
+        %{"name" => name} when is_binary(name) -> String.trim(name, ":")
+        _ -> nil
+      end,
+      fn {name, _url} -> name end,
+      patterns
+    )
+  end
+
+  defp process_remove_impl(object, extract_from_tag, extract_from_emoji, patterns) do
     processed_tag =
       Enum.filter(
         object["tag"],
         fn
-          %{"type" => "Emoji", "icon" => %{"url" => url}} when is_binary(url) ->
-            not match_any?(url, patterns)
+          %{"type" => "Emoji"} = tag ->
+            str = extract_from_tag.(tag)
+
+            if is_binary(str) do
+              not match_any?(str, patterns)
+            else
+              true
+            end
 
           _ ->
             true
@@ -61,8 +97,8 @@ defp process_remove(object, :url, patterns) do
     processed_emoji =
       if object["emoji"] do
         object["emoji"]
-        |> Enum.reduce(%{}, fn {name, url}, acc ->
-          if not match_any?(url, patterns) do
+        |> Enum.reduce(%{}, fn {name, url} = emoji, acc ->
+          if not match_any?(extract_from_emoji.(emoji), patterns) do
             Map.put(acc, name, url)
           else
             acc
diff --git a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
index fe1fb338e..6511f6532 100644
--- a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
+++ b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
@@ -120,4 +120,37 @@ test "processes status" do
       assert %{"object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}} = filtered
     end
   end
+
+  describe "remove_shortcode" do
+    setup do
+      clear_config([:mrf_emoji, :remove_shortcode], [
+        "test",
+        ~r{mikoto_s},
+        "nekomimi_girl_emoji"
+      ])
+
+      :ok
+    end
+
+    test "processes user" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @user_data)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      assert %{"tag" => ^expected_tags} = filtered
+    end
+
+    test "processes status" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{"object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}} = filtered
+    end
+  end
 end

From 7eb8abf7bb50e6bf4c6587ea308e1a52d944375a Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 28 Feb 2023 11:47:53 -0500
Subject: [PATCH 03/11] EmojiPolicy: Implement delist

---
 lib/pleroma/web/activity_pub/emoji_policy.ex  | 117 ++++++++++--
 .../activity_pub/mrf/emoji_policy_test.exs    | 180 +++++++++++++++++-
 2 files changed, 274 insertions(+), 23 deletions(-)

diff --git a/lib/pleroma/web/activity_pub/emoji_policy.ex b/lib/pleroma/web/activity_pub/emoji_policy.ex
index 346b64699..df1566ec3 100644
--- a/lib/pleroma/web/activity_pub/emoji_policy.ex
+++ b/lib/pleroma/web/activity_pub/emoji_policy.ex
@@ -5,6 +5,8 @@
 defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicy do
   require Pleroma.Constants
 
+  alias Pleroma.Object.Updater
+
   @moduledoc "Reject or force-unlisted emojis with certain URLs or names"
 
   @behaviour Pleroma.Web.ActivityPub.MRF.Policy
@@ -17,12 +19,31 @@ defp config_remove_shortcode do
     Pleroma.Config.get([:mrf_emoji, :remove_shortcode], [])
   end
 
+  defp config_unlist_url do
+    Pleroma.Config.get([:mrf_emoji, :federated_timeline_removal_url], [])
+  end
+
+  defp config_unlist_shortcode do
+    Pleroma.Config.get([:mrf_emoji, :federated_timeline_removal_shortcode], [])
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def history_awareness, do: :manual
+
   @impl Pleroma.Web.ActivityPub.MRF.Policy
   def filter(%{"type" => type, "object" => %{} = object} = message)
       when type in ["Create", "Update"] do
-    with object <- process_remove(object, :url, config_remove_url()),
-         object <- process_remove(object, :shortcode, config_remove_shortcode()) do
-      {:ok, Map.put(message, "object", object)}
+    with {:ok, object} <-
+           Updater.do_with_history(object, fn object ->
+             {:ok, process_remove(object, :url, config_remove_url())}
+           end),
+         {:ok, object} <-
+           Updater.do_with_history(object, fn object ->
+             {:ok, process_remove(object, :shortcode, config_remove_shortcode())}
+           end),
+         activity <- Map.put(message, "object", object),
+         activity <- maybe_delist(activity) do
+      {:ok, activity}
     end
   end
 
@@ -51,28 +72,22 @@ defp match_any?(string, patterns) do
     Enum.any?(patterns, &match_string?(string, &1))
   end
 
+  defp url_from_tag(%{"icon" => %{"url" => url}}), do: url
+  defp url_from_tag(_), do: nil
+
+  defp url_from_emoji({_name, url}), do: url
+
+  defp shortcode_from_tag(%{"name" => name}) when is_binary(name), do: String.trim(name, ":")
+  defp shortcode_from_tag(_), do: nil
+
+  defp shortcode_from_emoji({name, _url}), do: name
+
   defp process_remove(object, :url, patterns) do
-    process_remove_impl(
-      object,
-      fn
-        %{"icon" => %{"url" => url}} -> url
-        _ -> nil
-      end,
-      fn {_name, url} -> url end,
-      patterns
-    )
+    process_remove_impl(object, &url_from_tag/1, &url_from_emoji/1, patterns)
   end
 
   defp process_remove(object, :shortcode, patterns) do
-    process_remove_impl(
-      object,
-      fn
-        %{"name" => name} when is_binary(name) -> String.trim(name, ":")
-        _ -> nil
-      end,
-      fn {name, _url} -> name end,
-      patterns
-    )
+    process_remove_impl(object, &shortcode_from_tag/1, &shortcode_from_emoji/1, patterns)
   end
 
   defp process_remove_impl(object, extract_from_tag, extract_from_emoji, patterns) do
@@ -118,6 +133,66 @@ defp process_remove_impl(object, extract_from_tag, extract_from_emoji, patterns)
     end
   end
 
+  defp maybe_delist(%{"object" => object, "to" => to, "type" => "Create"} = activity) do
+    check = fn object ->
+      if any_emoji_match?(object, &url_from_tag/1, &url_from_emoji/1, config_unlist_url()) or
+           any_emoji_match?(
+             object,
+             &shortcode_from_tag/1,
+             &shortcode_from_emoji/1,
+             config_unlist_shortcode()
+           ) do
+        {:should_delist, nil}
+      else
+        {:ok, %{}}
+      end
+    end
+
+    should_delist? = fn object ->
+      with {:ok, _} <- Pleroma.Object.Updater.do_with_history(object, check) do
+        false
+      else
+        _ -> true
+      end
+    end
+
+    if Pleroma.Constants.as_public() in to and should_delist?.(object) do
+      to = List.delete(to, Pleroma.Constants.as_public())
+      cc = [Pleroma.Constants.as_public() | activity["cc"] || []]
+
+      activity
+      |> Map.put("to", to)
+      |> Map.put("cc", cc)
+    else
+      activity
+    end
+  end
+
+  defp maybe_delist(activity), do: activity
+
+  defp any_emoji_match?(object, extract_from_tag, extract_from_emoji, patterns) do
+    Kernel.||(
+      Enum.any?(
+        object["tag"],
+        fn
+          %{"type" => "Emoji"} = tag ->
+            str = extract_from_tag.(tag)
+
+            if is_binary(str) do
+              match_any?(str, patterns)
+            else
+              false
+            end
+
+          _ ->
+            false
+        end
+      ),
+      object["emoji"]
+      |> Enum.any?(fn emoji -> match_any?(extract_from_emoji.(emoji), patterns) end)
+    )
+  end
+
   @impl Pleroma.Web.ActivityPub.MRF.Policy
   def describe do
     # This horror is needed to convert regex sigils to strings
diff --git a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
index 6511f6532..1e1b5c578 100644
--- a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
+++ b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
@@ -5,6 +5,8 @@
 defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicyTest do
   use Pleroma.DataCase
 
+  require Pleroma.Constants
+
   alias Pleroma.Web.ActivityPub.MRF
   alias Pleroma.Web.ActivityPub.MRF.EmojiPolicy
 
@@ -84,8 +86,27 @@ defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicyTest do
         "nekomimi_girl_emoji_007" =>
           "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png",
         "test" => "https://example.org/test.png"
-      }
-    }
+      },
+      "to" => ["https://example.org/self", Pleroma.Constants.as_public()],
+      "cc" => ["https://example.org/someone"]
+    },
+    "to" => ["https://example.org/self", Pleroma.Constants.as_public()],
+    "cc" => ["https://example.org/someone"]
+  }
+
+  @status_data_with_history %{
+    "type" => "Create",
+    "object" =>
+      @status_data["object"]
+      |> Map.merge(%{
+        "formerRepresentations" => %{
+          "type" => "OrderedCollection",
+          "orderedItems" => [@status_data["object"] |> Map.put("content", "older")],
+          "totalItems" => 1
+        }
+      }),
+    "to" => ["https://example.org/self", Pleroma.Constants.as_public()],
+    "cc" => ["https://example.org/someone"]
   }
 
   describe "remove_url" do
@@ -119,6 +140,49 @@ test "processes status" do
 
       assert %{"object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}} = filtered
     end
+
+    test "processes status with history" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data_with_history)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{
+               "object" => %{
+                 "tag" => ^expected_tags,
+                 "emoji" => ^expected_emoji,
+                 "formerRepresentations" => %{"orderedItems" => [item]}
+               }
+             } = filtered
+
+      assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
+    end
+
+    test "processes updates" do
+      {:ok, filtered} =
+        MRF.filter_one(EmojiPolicy, @status_data_with_history |> Map.put("type", "Update"))
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{
+               "object" => %{
+                 "tag" => ^expected_tags,
+                 "emoji" => ^expected_emoji,
+                 "formerRepresentations" => %{"orderedItems" => [item]}
+               }
+             } = filtered
+
+      assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
+    end
   end
 
   describe "remove_shortcode" do
@@ -152,5 +216,117 @@ test "processes status" do
 
       assert %{"object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}} = filtered
     end
+
+    test "processes status with history" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data_with_history)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{
+               "object" => %{
+                 "tag" => ^expected_tags,
+                 "emoji" => ^expected_emoji,
+                 "formerRepresentations" => %{"orderedItems" => [item]}
+               }
+             } = filtered
+
+      assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
+    end
+
+    test "processes updates" do
+      {:ok, filtered} =
+        MRF.filter_one(EmojiPolicy, @status_data_with_history |> Map.put("type", "Update"))
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{
+               "object" => %{
+                 "tag" => ^expected_tags,
+                 "emoji" => ^expected_emoji,
+                 "formerRepresentations" => %{"orderedItems" => [item]}
+               }
+             } = filtered
+
+      assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
+    end
+  end
+
+  describe "federated_timeline_removal_url" do
+    setup do
+      clear_config([:mrf_emoji, :federated_timeline_removal_url], [
+        "https://example.org/test.png",
+        ~r{/biribiri/mikoto_smile[23]\.png},
+        "nekomimi_girl_emoji"
+      ])
+
+      :ok
+    end
+
+    test "processes status" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data)
+
+      expected_tags = @status_data["object"]["tag"]
+      expected_emoji = @status_data["object"]["emoji"]
+
+      expected_to = ["https://example.org/self"]
+      expected_cc = [Pleroma.Constants.as_public(), "https://example.org/someone"]
+
+      assert %{
+               "to" => ^expected_to,
+               "cc" => ^expected_cc,
+               "object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}
+             } = filtered
+    end
+
+    test "ignore updates" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data |> Map.put("type", "Update"))
+
+      expected_tags = @status_data["object"]["tag"]
+      expected_emoji = @status_data["object"]["emoji"]
+
+      expected_to = ["https://example.org/self", Pleroma.Constants.as_public()]
+      expected_cc = ["https://example.org/someone"]
+
+      assert %{
+               "to" => ^expected_to,
+               "cc" => ^expected_cc,
+               "object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}
+             } = filtered
+    end
+
+    test "processes status with history" do
+      status =
+        @status_data_with_history
+        |> put_in(["object", "tag"], @misc_tags)
+        |> put_in(["object", "emoji"], %{})
+
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, status)
+
+      expected_tags = @status_data["object"]["tag"]
+      expected_emoji = @status_data["object"]["emoji"]
+
+      expected_to = ["https://example.org/self"]
+      expected_cc = [Pleroma.Constants.as_public(), "https://example.org/someone"]
+
+      assert %{
+               "to" => ^expected_to,
+               "cc" => ^expected_cc,
+               "object" => %{
+                 "formerRepresentations" => %{
+                   "orderedItems" => [%{"tag" => ^expected_tags, "emoji" => ^expected_emoji}]
+                 }
+               }
+             } = filtered
+    end
   end
 end

From f50422c3802cd2316cfa6312d5a88c018c722843 Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 28 Feb 2023 11:48:34 -0500
Subject: [PATCH 04/11] Move emoji_policy.ex to the right place

---
 lib/pleroma/web/activity_pub/{ => mrf}/emoji_policy.ex | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename lib/pleroma/web/activity_pub/{ => mrf}/emoji_policy.ex (100%)

diff --git a/lib/pleroma/web/activity_pub/emoji_policy.ex b/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
similarity index 100%
rename from lib/pleroma/web/activity_pub/emoji_policy.ex
rename to lib/pleroma/web/activity_pub/mrf/emoji_policy.ex

From 18a8378beb01a7ee93afcddf16e2699c5fe6d35a Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 28 Feb 2023 12:05:54 -0500
Subject: [PATCH 05/11] Update config cheatsheet

---
 docs/configuration/cheatsheet.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/docs/configuration/cheatsheet.md b/docs/configuration/cheatsheet.md
index 1e49a79d0..696d10e74 100644
--- a/docs/configuration/cheatsheet.md
+++ b/docs/configuration/cheatsheet.md
@@ -261,6 +261,11 @@ Notes:
 
 * `follower_nickname`: The name of the bot account to use for following newly discovered users. Using `followbot` or similar is strongly suggested.
 
+#### :mrf_emoji
+* `remove_url`: A list of patterns which result in emoji whose URL matches being removed from the message. This will apply to both statuses and user profiles. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
+* `remove_shortcode`: A list of patterns which result in emoji whose shortcode matches being removed from the message. This will apply to both statuses and user profiles. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
+* `federated_timeline_removal_url`: A list of patterns which result in message with emojis whose URLs match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
+* `federated_timeline_removal_shortcode`: A list of patterns which result in message with emojis whose shortcodes match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
 
 ### :activitypub
 * `unfollow_blocked`: Whether blocks result in people getting unfollowed

From 20d193c91da587372c618c53020a1f90eff20a7b Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 28 Feb 2023 12:14:48 -0500
Subject: [PATCH 06/11] Improve config examples for EmojiPolicy

---
 lib/pleroma/web/activity_pub/mrf/emoji_policy.ex | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex b/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
index df1566ec3..9a2e8eade 100644
--- a/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
@@ -231,7 +231,7 @@ def config_description do
 
             Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
           """,
-          suggestions: ["foo", ~r/foo/iu]
+          suggestions: ["https://example.org/foo.png", ~r/example.org\/foo/iu]
         },
         %{
           key: :remove_shortcode,
@@ -251,7 +251,7 @@ def config_description do
 
             Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
           """,
-          suggestions: ["foo", ~r/foo/iu]
+          suggestions: ["https://example.org/foo.png", ~r/example.org\/foo/iu]
         },
         %{
           key: :federated_timeline_removal_shortcode,

From ef8a6c539a98633d1a78fa42379952b93f847309 Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 13 Jun 2023 14:53:20 -0400
Subject: [PATCH 07/11] Make EmojiPolicy aware of custom emoji reactions

---
 docs/configuration/cheatsheet.md              |  4 +-
 .../web/activity_pub/mrf/emoji_policy.ex      | 33 +++++++++----
 .../activity_pub/mrf/emoji_policy_test.exs    | 46 +++++++++++++++++++
 3 files changed, 72 insertions(+), 11 deletions(-)

diff --git a/docs/configuration/cheatsheet.md b/docs/configuration/cheatsheet.md
index 696d10e74..f43cde114 100644
--- a/docs/configuration/cheatsheet.md
+++ b/docs/configuration/cheatsheet.md
@@ -262,8 +262,8 @@ Notes:
 * `follower_nickname`: The name of the bot account to use for following newly discovered users. Using `followbot` or similar is strongly suggested.
 
 #### :mrf_emoji
-* `remove_url`: A list of patterns which result in emoji whose URL matches being removed from the message. This will apply to both statuses and user profiles. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
-* `remove_shortcode`: A list of patterns which result in emoji whose shortcode matches being removed from the message. This will apply to both statuses and user profiles. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
+* `remove_url`: A list of patterns which result in emoji whose URL matches being removed from the message. This will apply to statuses, emoji reactions, and user profiles. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
+* `remove_shortcode`: A list of patterns which result in emoji whose shortcode matches being removed from the message. This will apply to statuses, emoji reactions, and user profiles. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
 * `federated_timeline_removal_url`: A list of patterns which result in message with emojis whose URLs match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
 * `federated_timeline_removal_shortcode`: A list of patterns which result in message with emojis whose shortcodes match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
 
diff --git a/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex b/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
index 9a2e8eade..13201ac55 100644
--- a/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
@@ -55,6 +55,17 @@ def filter(%{"type" => type} = object) when type in Pleroma.Constants.actor_type
     end
   end
 
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def filter(%{"type" => "EmojiReact"} = object) do
+    with {:ok, _} <-
+           matched_emoji_checker(config_remove_url(), config_remove_shortcode()).(object) do
+      {:ok, object}
+    else
+      _ ->
+        {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"}
+    end
+  end
+
   @impl Pleroma.Web.ActivityPub.MRF.Policy
   def filter(message) do
     {:ok, message}
@@ -133,20 +144,24 @@ defp process_remove_impl(object, extract_from_tag, extract_from_emoji, patterns)
     end
   end
 
-  defp maybe_delist(%{"object" => object, "to" => to, "type" => "Create"} = activity) do
-    check = fn object ->
-      if any_emoji_match?(object, &url_from_tag/1, &url_from_emoji/1, config_unlist_url()) or
+  defp matched_emoji_checker(urls, shortcodes) do
+    fn object ->
+      if any_emoji_match?(object, &url_from_tag/1, &url_from_emoji/1, urls) or
            any_emoji_match?(
              object,
              &shortcode_from_tag/1,
              &shortcode_from_emoji/1,
-             config_unlist_shortcode()
+             shortcodes
            ) do
-        {:should_delist, nil}
+        {:matched, nil}
       else
         {:ok, %{}}
       end
     end
+  end
+
+  defp maybe_delist(%{"object" => object, "to" => to, "type" => "Create"} = activity) do
+    check = matched_emoji_checker(config_unlist_url(), config_unlist_shortcode())
 
     should_delist? = fn object ->
       with {:ok, _} <- Pleroma.Object.Updater.do_with_history(object, check) do
@@ -173,7 +188,7 @@ defp maybe_delist(activity), do: activity
   defp any_emoji_match?(object, extract_from_tag, extract_from_emoji, patterns) do
     Kernel.||(
       Enum.any?(
-        object["tag"],
+        object["tag"] || [],
         fn
           %{"type" => "Emoji"} = tag ->
             str = extract_from_tag.(tag)
@@ -188,7 +203,7 @@ defp any_emoji_match?(object, extract_from_tag, extract_from_emoji, patterns) do
             false
         end
       ),
-      object["emoji"]
+      (object["emoji"] || [])
       |> Enum.any?(fn emoji -> match_any?(extract_from_emoji.(emoji), patterns) end)
     )
   end
@@ -227,7 +242,7 @@ def config_description do
           key: :remove_url,
           type: {:list, :string},
           description: """
-            A list of patterns which result in emoji whose URL matches being removed from the message. This will apply to both statuses and user profiles.
+            A list of patterns which result in emoji whose URL matches being removed from the message. This will apply to statuses, emoji reactions, and user profiles.
 
             Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
           """,
@@ -237,7 +252,7 @@ def config_description do
           key: :remove_shortcode,
           type: {:list, :string},
           description: """
-            A list of patterns which result in emoji whose shortcode matches being removed from the message. This will apply to both statuses and user profiles.
+            A list of patterns which result in emoji whose shortcode matches being removed from the message. This will apply to statuses, emoji reactions, and user profiles.
 
             Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
           """,
diff --git a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
index 1e1b5c578..ae4c44f1c 100644
--- a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
+++ b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
@@ -109,6 +109,30 @@ defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicyTest do
     "cc" => ["https://example.org/someone"]
   }
 
+  @emoji_react_data %{
+    "type" => "EmojiReact",
+    "tag" => [@emoji_tags |> Enum.at(3)],
+    "object" => "https://example.org/someobject",
+    "to" => ["https://example.org/self"],
+    "cc" => ["https://example.org/someone"]
+  }
+
+  @emoji_react_data_matching_regex %{
+    "type" => "EmojiReact",
+    "tag" => [@emoji_tags |> Enum.at(1)],
+    "object" => "https://example.org/someobject",
+    "to" => ["https://example.org/self"],
+    "cc" => ["https://example.org/someone"]
+  }
+
+  @emoji_react_data_matching_nothing %{
+    "type" => "EmojiReact",
+    "tag" => [@emoji_tags |> Enum.at(2)],
+    "object" => "https://example.org/someobject",
+    "to" => ["https://example.org/self"],
+    "cc" => ["https://example.org/someone"]
+  }
+
   describe "remove_url" do
     setup do
       clear_config([:mrf_emoji, :remove_url], [
@@ -183,6 +207,17 @@ test "processes updates" do
 
       assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
     end
+
+    test "processes EmojiReact" do
+      assert {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data)
+
+      assert {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_regex)
+
+      assert {:ok, @emoji_react_data_matching_nothing} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_nothing)
+    end
   end
 
   describe "remove_shortcode" do
@@ -259,6 +294,17 @@ test "processes updates" do
 
       assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
     end
+
+    test "processes EmojiReact" do
+      assert {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data)
+
+      assert {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_regex)
+
+      assert {:ok, @emoji_react_data_matching_nothing} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_nothing)
+    end
   end
 
   describe "federated_timeline_removal_url" do

From d670dbdbd3e675b7d29c97e8bfd5301dcf3c9de0 Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 13 Jun 2023 14:55:27 -0400
Subject: [PATCH 08/11] Test that unicode emoji reactions are not affected

---
 .../web/activity_pub/mrf/emoji_policy_test.exs     | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
index ae4c44f1c..121ee1ea0 100644
--- a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
+++ b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
@@ -133,6 +133,14 @@ defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicyTest do
     "cc" => ["https://example.org/someone"]
   }
 
+  @emoji_react_data_unicode %{
+    "type" => "EmojiReact",
+    "content" => "😍",
+    "object" => "https://example.org/someobject",
+    "to" => ["https://example.org/self"],
+    "cc" => ["https://example.org/someone"]
+  }
+
   describe "remove_url" do
     setup do
       clear_config([:mrf_emoji, :remove_url], [
@@ -217,6 +225,9 @@ test "processes EmojiReact" do
 
       assert {:ok, @emoji_react_data_matching_nothing} ==
                MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_nothing)
+
+      assert {:ok, @emoji_react_data_unicode} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_unicode)
     end
   end
 
@@ -304,6 +315,9 @@ test "processes EmojiReact" do
 
       assert {:ok, @emoji_react_data_matching_nothing} ==
                MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_nothing)
+
+      assert {:ok, @emoji_react_data_unicode} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_unicode)
     end
   end
 

From 0d914e17bedb49a5efb8c0268d4a6df2e7ffdf96 Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 13 Jun 2023 14:56:16 -0400
Subject: [PATCH 09/11] Add changelog

---
 changelog.d/emoji-policy.add | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/emoji-policy.add

diff --git a/changelog.d/emoji-policy.add b/changelog.d/emoji-policy.add
new file mode 100644
index 000000000..45510c4f6
--- /dev/null
+++ b/changelog.d/emoji-policy.add
@@ -0,0 +1 @@
+Implement MRF policy to reject or delist according to emojis

From ba3aa4f86da77ece8ac472c40da180ab1921c304 Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Tue, 20 Jun 2023 10:14:01 -0400
Subject: [PATCH 10/11] Fix edge cases

---
 lib/pleroma/constants.ex                      | 12 +++
 .../web/activity_pub/mrf/emoji_policy.ex      | 79 ++++++++++---------
 .../activity_pub/mrf/emoji_policy_test.exs    | 33 ++++++++
 3 files changed, 87 insertions(+), 37 deletions(-)

diff --git a/lib/pleroma/constants.ex b/lib/pleroma/constants.ex
index cfb405218..7b4fd03b6 100644
--- a/lib/pleroma/constants.ex
+++ b/lib/pleroma/constants.ex
@@ -42,6 +42,18 @@ defmodule Pleroma.Constants do
     ]
   )
 
+  const(status_object_types,
+    do: [
+      "Note",
+      "Question",
+      "Audio",
+      "Video",
+      "Event",
+      "Article",
+      "Page"
+    ]
+  )
+
   const(updatable_object_types,
     do: [
       "Note",
diff --git a/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex b/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
index 13201ac55..95d6a6d43 100644
--- a/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
@@ -31,8 +31,8 @@ defp config_unlist_shortcode do
   def history_awareness, do: :manual
 
   @impl Pleroma.Web.ActivityPub.MRF.Policy
-  def filter(%{"type" => type, "object" => %{} = object} = message)
-      when type in ["Create", "Update"] do
+  def filter(%{"type" => type, "object" => %{"type" => objtype} = object} = message)
+      when type in ["Create", "Update"] and objtype in Pleroma.Constants.status_object_types() do
     with {:ok, object} <-
            Updater.do_with_history(object, fn object ->
              {:ok, process_remove(object, :url, config_remove_url())}
@@ -102,46 +102,51 @@ defp process_remove(object, :shortcode, patterns) do
   end
 
   defp process_remove_impl(object, extract_from_tag, extract_from_emoji, patterns) do
-    processed_tag =
-      Enum.filter(
-        object["tag"],
-        fn
-          %{"type" => "Emoji"} = tag ->
-            str = extract_from_tag.(tag)
+    object =
+      if object["tag"] do
+        Map.put(
+          object,
+          "tag",
+          Enum.filter(
+            object["tag"],
+            fn
+              %{"type" => "Emoji"} = tag ->
+                str = extract_from_tag.(tag)
 
-            if is_binary(str) do
-              not match_any?(str, patterns)
-            else
-              true
+                if is_binary(str) do
+                  not match_any?(str, patterns)
+                else
+                  true
+                end
+
+              _ ->
+                true
             end
-
-          _ ->
-            true
-        end
-      )
-
-    processed_emoji =
-      if object["emoji"] do
-        object["emoji"]
-        |> Enum.reduce(%{}, fn {name, url} = emoji, acc ->
-          if not match_any?(extract_from_emoji.(emoji), patterns) do
-            Map.put(acc, name, url)
-          else
-            acc
-          end
-        end)
+          )
+        )
       else
-        nil
+        object
       end
 
-    if processed_emoji do
-      object
-      |> Map.put("tag", processed_tag)
-      |> Map.put("emoji", processed_emoji)
-    else
-      object
-      |> Map.put("tag", processed_tag)
-    end
+    object =
+      if object["emoji"] do
+        Map.put(
+          object,
+          "emoji",
+          object["emoji"]
+          |> Enum.reduce(%{}, fn {name, url} = emoji, acc ->
+            if not match_any?(extract_from_emoji.(emoji), patterns) do
+              Map.put(acc, name, url)
+            else
+              acc
+            end
+          end)
+        )
+      else
+        object
+      end
+
+    object
   end
 
   defp matched_emoji_checker(urls, shortcodes) do
diff --git a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
index 121ee1ea0..7350800f0 100644
--- a/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
+++ b/test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs
@@ -389,4 +389,37 @@ test "processes status with history" do
              } = filtered
     end
   end
+
+  describe "edge cases" do
+    setup do
+      clear_config([:mrf_emoji, :remove_url], [
+        "https://example.org/test.png",
+        ~r{/biribiri/mikoto_smile[23]\.png},
+        "nekomimi_girl_emoji"
+      ])
+
+      :ok
+    end
+
+    test "non-statuses" do
+      answer = @status_data |> put_in(["object", "type"], "Answer")
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, answer)
+
+      assert filtered == answer
+    end
+
+    test "without tag" do
+      status = @status_data |> Map.put("object", Map.drop(@status_data["object"], ["tag"]))
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, status)
+
+      refute Map.has_key?(filtered["object"], "tag")
+    end
+
+    test "without emoji" do
+      status = @status_data |> Map.put("object", Map.drop(@status_data["object"], ["emoji"]))
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, status)
+
+      refute Map.has_key?(filtered["object"], "emoji")
+    end
+  end
 end

From 1459d64508b10725231d8f4256fbc68166c1b8ae Mon Sep 17 00:00:00 2001
From: tusooa <tusooa@kazv.moe>
Date: Fri, 7 Jul 2023 07:09:35 -0400
Subject: [PATCH 11/11] Make regex-to-string descriptor reusable

---
 .../web/activity_pub/mrf/emoji_policy.ex      | 12 ++----------
 .../web/activity_pub/mrf/keyword_policy.ex    | 16 ++++------------
 lib/pleroma/web/activity_pub/mrf/utils.ex     | 15 +++++++++++++++
 .../web/activity_pub/mrf/utils_test.exs       | 19 +++++++++++++++++++
 4 files changed, 40 insertions(+), 22 deletions(-)
 create mode 100644 lib/pleroma/web/activity_pub/mrf/utils.ex
 create mode 100644 test/pleroma/web/activity_pub/mrf/utils_test.exs

diff --git a/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex b/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
index 95d6a6d43..f884962b9 100644
--- a/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/emoji_policy.ex
@@ -6,6 +6,7 @@ defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicy do
   require Pleroma.Constants
 
   alias Pleroma.Object.Updater
+  alias Pleroma.Web.ActivityPub.MRF.Utils
 
   @moduledoc "Reject or force-unlisted emojis with certain URLs or names"
 
@@ -215,19 +216,10 @@ defp any_emoji_match?(object, extract_from_tag, extract_from_emoji, patterns) do
 
   @impl Pleroma.Web.ActivityPub.MRF.Policy
   def describe do
-    # This horror is needed to convert regex sigils to strings
     mrf_emoji =
       Pleroma.Config.get(:mrf_emoji, [])
       |> Enum.map(fn {key, value} ->
-        {key,
-         Enum.map(value, fn
-           pattern ->
-             if not is_binary(pattern) do
-               inspect(pattern)
-             else
-               pattern
-             end
-         end)}
+        {key, Enum.map(value, &Utils.describe_regex_or_string/1)}
       end)
       |> Enum.into(%{})
 
diff --git a/lib/pleroma/web/activity_pub/mrf/keyword_policy.ex b/lib/pleroma/web/activity_pub/mrf/keyword_policy.ex
index 687ec6c2f..874fe9ab9 100644
--- a/lib/pleroma/web/activity_pub/mrf/keyword_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/keyword_policy.ex
@@ -5,6 +5,8 @@
 defmodule Pleroma.Web.ActivityPub.MRF.KeywordPolicy do
   require Pleroma.Constants
 
+  alias Pleroma.Web.ActivityPub.MRF.Utils
+
   @moduledoc "Reject or Word-Replace messages with a keyword or regex"
 
   @behaviour Pleroma.Web.ActivityPub.MRF.Policy
@@ -128,7 +130,6 @@ def filter(message), do: {:ok, message}
 
   @impl true
   def describe do
-    # This horror is needed to convert regex sigils to strings
     mrf_keyword =
       Pleroma.Config.get(:mrf_keyword, [])
       |> Enum.map(fn {key, value} ->
@@ -136,21 +137,12 @@ def describe do
          Enum.map(value, fn
            {pattern, replacement} ->
              %{
-               "pattern" =>
-                 if not is_binary(pattern) do
-                   inspect(pattern)
-                 else
-                   pattern
-                 end,
+               "pattern" => Utils.describe_regex_or_string(pattern),
                "replacement" => replacement
              }
 
            pattern ->
-             if not is_binary(pattern) do
-               inspect(pattern)
-             else
-               pattern
-             end
+             Utils.describe_regex_or_string(pattern)
          end)}
       end)
       |> Enum.into(%{})
diff --git a/lib/pleroma/web/activity_pub/mrf/utils.ex b/lib/pleroma/web/activity_pub/mrf/utils.ex
new file mode 100644
index 000000000..f2dc9eea9
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/mrf/utils.ex
@@ -0,0 +1,15 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.Utils do
+  @spec describe_regex_or_string(String.t() | Regex.t()) :: String.t()
+  def describe_regex_or_string(pattern) do
+    # This horror is needed to convert regex sigils to strings
+    if not is_binary(pattern) do
+      inspect(pattern)
+    else
+      pattern
+    end
+  end
+end
diff --git a/test/pleroma/web/activity_pub/mrf/utils_test.exs b/test/pleroma/web/activity_pub/mrf/utils_test.exs
new file mode 100644
index 000000000..3bbc2cfd3
--- /dev/null
+++ b/test/pleroma/web/activity_pub/mrf/utils_test.exs
@@ -0,0 +1,19 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.UtilsTest do
+  use Pleroma.DataCase, async: true
+
+  alias Pleroma.Web.ActivityPub.MRF.Utils
+
+  describe "describe_regex_or_string/1" do
+    test "describes regex" do
+      assert "~r/foo/i" == Utils.describe_regex_or_string(~r/foo/i)
+    end
+
+    test "returns string as-is" do
+      assert "foo" == Utils.describe_regex_or_string("foo")
+    end
+  end
+end