Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `README.md`:
  Upstream README has been changed, but we have a completely different one.
  Kept our `README.md`.
- `lib/sanitize_ext/sanitize_config.rb`:
  Upstream added support for more incoming HTML tags (a large subset of what
  glitch-soc accepts).
  Change the code style to match upstream's but otherwise do not change our
  code.
- `spec/lib/sanitize_config_spec.rb`:
  Upstream added support for more incoming HTML tags (a large subset of what
  glitch-soc accepts).
  Kept our version, since the tests are mostly glitch-soc's, except for cases
  which are purposefuly different.

app/workers/activitypub/delivery_worker.rb

@@ -10,6 +10,16 @@ class ActivityPub::DeliveryWorker
 
   sidekiq_options queue: 'push', retry: 16, dead: false
 
+  # Unfortunately, we cannot control Sidekiq's jitter, so add our own
+  sidekiq_retry_in do |count|
+    # This is Sidekiq's default delay
+    delay  = (count**4) + 15
+    # Our custom jitter, that will be added to Sidekiq's built-in one.
+    # Sidekiq's built-in jitter is `rand(10) * (count + 1)`
+    jitter = rand(0.5 * (count**4))
+    delay + jitter
+  end
+
   HEADERS = { 'Content-Type' => 'application/activity+json' }.freeze
 
   def perform(json, source_account_id, inbox_url, options = {})

app/workers/activitypub/migrated_follow_delivery_worker.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class ActivityPub::MigratedFollowDeliveryWorker < ActivityPub::DeliveryWorker
+  def perform(json, source_account_id, inbox_url, old_target_account_id, options = {})
+    super(json, source_account_id, inbox_url, options)
+    unfollow_old_account!(old_target_account_id)
+  end
+
+  private
+
+  def unfollow_old_account!(old_target_account_id)
+    old_target_account = Account.find(old_target_account_id)
+    UnfollowService.new.call(@source_account, old_target_account, skip_unmerge: true)
+  rescue
+    true
+  end
+end