Deprectate strings for SimplePolicy

When strings are detected in the simplepolicy, a warning will be given and the config will be changed to use tuples instead

lib/pleroma/config/deprecation_warnings.ex

@@ -20,6 +20,68 @@ defmodule Pleroma.Config.DeprecationWarnings do
      "\n* `config :pleroma, :instance, mrf_transparency_exclusions` is now `config :pleroma, :mrf, transparency_exclusions`"}
   ]
 
+  def check_simple_policy_tuples do
+    has_strings =
+      Config.get([:mrf_simple])
+      |> Enum.map(fn {_, v} -> v == [] || Enum.max(v) end)
+      |> Enum.max()
+      |> is_binary
+
+    if has_strings do
+      Logger.warn("""
+      !!!DEPRECATION WARNING!!!
+      Your config is using strings in the SimplePolicy configuration instead of tuples. They should work for now, but you are advised to change to the new configuration to prevent possible issues later:
+
+      ```
+      config :pleroma, :mrf_simple,
+        media_removal: ["instance.tld"],
+        media_nsfw: ["instance.tld"],
+        federated_timeline_removal: ["instance.tld"],
+        report_removal: ["instance.tld"],
+        reject: ["instance.tld"],
+        followers_only: ["instance.tld"],
+        accept: ["instance.tld"],
+        avatar_removal: ["instance.tld"],
+        banner_removal: ["instance.tld"],
+        reject_deletes: ["instance.tld"]
+      ```
+
+      Is now
+
+
+      ```
+      config :pleroma, :mrf_simple,
+        media_removal: [{"instance.tld", "Reason for media removal"}],
+        media_nsfw: [{"instance.tld", "Reason for media nsfw"}],
+        federated_timeline_removal: [{"instance.tld", "Reason for federated timeline removal"}],
+        report_removal: [{"instance.tld", "Reason for report removal"}],
+        reject: [{"instance.tld", "Reason for reject"}],
+        followers_only: [{"instance.tld", "Reason for followers only"}],
+        accept: [{"instance.tld", "Reason for accept"}],
+        avatar_removal: [{"instance.tld", "Reason for avatar removal"}],
+        banner_removal: [{"instance.tld", "Reason for banner removal"}],
+        reject_deletes: [{"instance.tld", "Reason for reject deletes"}]
+      ```
+      """)
+
+      new_config =
+        Config.get([:mrf_simple])
+        |> Enum.map(fn {k, v} ->
+          {k,
+           Enum.map(v, fn
+             {instance, reason} -> {instance, reason}
+             instance -> {instance, ""}
+           end)}
+        end)
+
+      Config.put([:mrf_simple], new_config)
+
+      :ok
+    else
+      :ok
+    end
+  end
+
   def check_hellthread_threshold do
     if Config.get([:mrf_hellthread, :threshold]) do
       Logger.warn("""
@@ -59,7 +121,8 @@ def mrf_user_allowlist do
   end
 
   def warn do
-    with :ok <- check_hellthread_threshold(),
+    with :ok <- check_simple_policy_tuples(),
+         :ok <- check_hellthread_threshold(),
          :ok <- mrf_user_allowlist(),
          :ok <- check_old_mrf_config(),
          :ok <- check_media_proxy_whitelist_config(),

test/config/deprecation_warnings_test.exs

@@ -7,6 +7,83 @@ defmodule Pleroma.Config.DeprecationWarningsTest do
   alias Pleroma.Config
   alias Pleroma.Config.DeprecationWarnings
 
+  describe "simple policy tuples" do
+    test "gives warning when there are still strings" do
+      clear_config([:mrf_simple],
+        media_removal: ["some.removal"],
+        media_nsfw: ["some.nsfw"],
+        federated_timeline_removal: ["some.tl.removal"],
+        report_removal: ["some.report.removal"],
+        reject: ["some.reject"],
+        followers_only: ["some.followers.only"],
+        accept: ["some.accept"],
+        avatar_removal: ["some.avatar.removal"],
+        banner_removal: ["some.banner.removal"],
+        reject_deletes: ["some.reject.deletes"]
+      )
+
+      # TODO: Can I take the actual config and new config instead? Note that it'll need to be clear where you put the reason.
+      assert capture_log(fn -> DeprecationWarnings.check_simple_policy_tuples() end) =~
+               """
+               !!!DEPRECATION WARNING!!!
+               Your config is using strings in the SimplePolicy configuration instead of tuples. They should work for now, but you are advised to change to the new configuration to prevent possible issues later:
+
+               ```
+               config :pleroma, :mrf_simple,
+                 media_removal: ["instance.tld"],
+                 media_nsfw: ["instance.tld"],
+                 federated_timeline_removal: ["instance.tld"],
+                 report_removal: ["instance.tld"],
+                 reject: ["instance.tld"],
+                 followers_only: ["instance.tld"],
+                 accept: ["instance.tld"],
+                 avatar_removal: ["instance.tld"],
+                 banner_removal: ["instance.tld"],
+                 reject_deletes: ["instance.tld"]
+               ```
+
+               Is now
+
+
+               ```
+               config :pleroma, :mrf_simple,
+                 media_removal: [{"instance.tld", "Reason for media removal"}],
+                 media_nsfw: [{"instance.tld", "Reason for media nsfw"}],
+                 federated_timeline_removal: [{"instance.tld", "Reason for federated timeline removal"}],
+                 report_removal: [{"instance.tld", "Reason for report removal"}],
+                 reject: [{"instance.tld", "Reason for reject"}],
+                 followers_only: [{"instance.tld", "Reason for followers only"}],
+                 accept: [{"instance.tld", "Reason for accept"}],
+                 avatar_removal: [{"instance.tld", "Reason for avatar removal"}],
+                 banner_removal: [{"instance.tld", "Reason for banner removal"}],
+                 reject_deletes: [{"instance.tld", "Reason for reject deletes"}]
+               ```
+               """
+    end
+
+    test "transforms config to tuples" do
+      clear_config([:mrf_simple],
+        media_removal: ["some.removal", {"some.other.instance", "Some reason"}]
+      )
+
+      expected_config = [
+        {:media_removal, [{"some.removal", ""}, {"some.other.instance", "Some reason"}]}
+      ]
+
+      capture_log(fn -> DeprecationWarnings.check_simple_policy_tuples() end)
+
+      assert Config.get([:mrf_simple]) == expected_config
+    end
+
+    test "doesn't give a warning with correct config" do
+      clear_config([:mrf_simple],
+        media_removal: [{"some.removal", ""}, {"some.other.instance", "Some reason"}]
+      )
+
+      assert capture_log(fn -> DeprecationWarnings.check_simple_policy_tuples() end) == ""
+    end
+  end
+
   test "check_old_mrf_config/0" do
     clear_config([:instance, :rewrite_policy], Pleroma.Web.ActivityPub.MRF.NoOpPolicy)
     clear_config([:instance, :mrf_transparency], true)