CommonFields: Use BareUri for :url

Closes: https://git.pleroma.social/pleroma/pleroma/-/issues/3121

changelog.d/3884.fix

@@ -0,0 +1 @@
+Allow non-HTTP(s) URIs in "url" fields for compatibility with "FEP-fffd: Proxy Objects"

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

@@ -58,7 +58,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFields do
       field(:like_count, :integer, default: 0)
       field(:announcement_count, :integer, default: 0)
       field(:inReplyTo, ObjectValidators.ObjectID)
-      field(:url, ObjectValidators.Uri)
+      field(:url, ObjectValidators.BareUri)
 
       field(:likes, {:array, ObjectValidators.ObjectID}, default: [])
       field(:announcements, {:array, ObjectValidators.ObjectID}, default: [])

test/pleroma/ecto_type/activity_pub/object_validators/bare_uri_test.ex

@@ -0,0 +1,25 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.EctoType.ActivityPub.ObjectValidators.BareUriTest do
+  use Pleroma.DataCase, async: true
+
+  alias Pleroma.EctoType.ActivityPub.ObjectValidators.BareUri
+
+  test "diaspora://" do
+    text = "diaspora://alice@fediverse.example/post/deadbeefdeadbeefdeadbeefdeadbeef"
+    assert {:ok, text} = BareUri.cast(text)
+  end
+
+  test "nostr:" do
+    text = "nostr:note1gwdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef"
+    assert {:ok, text} = BareUri.cast(text)
+  end
+
+  test "errors for non-URIs" do
+    assert :error == SafeText.cast(1)
+    assert :error == SafeText.cast("foo")
+    assert :error == SafeText.cast("foo bar")
+  end
+end