Make regex-to-string descriptor reusable

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(%{})
 

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(%{})

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

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