Fix various issues with account migration (#12301)

* Fix being able to follow oneself by moving to an account that was following the old one

* Add specs

* Add spec to catch MoveWorker issue with local followers following both accounts

* Fix move worker breaking when a local account follows both source and target accounts

* Fix migration from remote to local account not sending Undo Follow

* Fix show_reblogs not being preserved for moved account's followers

3 files changed, 13 insertions, 6 deletions

diff --git a/app/services/follow_service.rb b/app/services/follow_service.rb
index 1941c2e2d..dc47804c0 100644
--- a/app/services/follow_service.rb
+++ b/app/services/follow_service.rb
@@ -8,7 +8,7 @@ class FollowService < BaseService
   # @param [Account] source_account From which to follow
   # @param [String, Account] uri User URI to follow in the form of username@domain (or account record)
   # @param [true, false, nil] reblogs Whether or not to show reblogs, defaults to true
-  def call(source_account, target_account, reblogs: nil)
+  def call(source_account, target_account, reblogs: nil, bypass_locked: false)
     reblogs = true if reblogs.nil?
     target_account = ResolveAccountService.new.call(target_account, skip_webfinger: true)
 
@@ -30,7 +30,7 @@ class FollowService < BaseService
 
     ActivityTracker.increment('activity:interactions')
 
-    if target_account.locked? || source_account.silenced? || target_account.activitypub?
+    if (target_account.locked? && !bypass_locked) || source_account.silenced? || target_account.activitypub?
       request_follow(source_account, target_account, reblogs: reblogs)
     elsif target_account.local?
       direct_follow(source_account, target_account, reblogs: reblogs)
diff --git a/app/workers/move_worker.rb b/app/workers/move_worker.rb
index 83f7090ee..595730226 100644
--- a/app/workers/move_worker.rb
+++ b/app/workers/move_worker.rb
@@ -7,7 +7,7 @@ class MoveWorker
     @source_account = Account.find(source_account_id)
     @target_account = Account.find(target_account_id)
 
-    if @target_account.local?
+    if @target_account.local? && @source_account.local?
       rewrite_follows!
     else
       queue_follow_unfollows!
@@ -21,13 +21,17 @@ class MoveWorker
   def rewrite_follows!
     @source_account.passive_relationships
                    .where(account: Account.local)
+                   .where.not(account: @target_account.followers.local)
+                   .where.not(account_id: @target_account.id)
                    .in_batches
                    .update_all(target_account_id: @target_account.id)
   end
 
   def queue_follow_unfollows!
+    bypass_locked = @target_account.local?
+
     @source_account.followers.local.select(:id).find_in_batches do |accounts|
-      UnfollowFollowWorker.push_bulk(accounts.map(&:id)) { |follower_id| [follower_id, @source_account.id, @target_account.id] }
+      UnfollowFollowWorker.push_bulk(accounts.map(&:id)) { |follower_id| [follower_id, @source_account.id, @target_account.id, bypass_locked] }
     end
   end
 end
diff --git a/app/workers/unfollow_follow_worker.rb b/app/workers/unfollow_follow_worker.rb
index 95549e107..b6e665a41 100644
--- a/app/workers/unfollow_follow_worker.rb
+++ b/app/workers/unfollow_follow_worker.rb
@@ -5,12 +5,15 @@ class UnfollowFollowWorker
 
   sidekiq_options queue: 'pull'
 
-  def perform(follower_account_id, old_target_account_id, new_target_account_id)
+  def perform(follower_account_id, old_target_account_id, new_target_account_id, bypass_locked = false)
     follower_account   = Account.find(follower_account_id)
     old_target_account = Account.find(old_target_account_id)
     new_target_account = Account.find(new_target_account_id)
 
-    FollowService.new.call(follower_account, new_target_account)
+    follow = follower_account.active_relationships.find_by(target_account: old_target_account)
+    reblogs = follow&.show_reblogs?
+
+    FollowService.new.call(follower_account, new_target_account, reblogs: reblogs, bypass_locked: bypass_locked)
     UnfollowService.new.call(follower_account, old_target_account, skip_unmerge: true)
   rescue ActiveRecord::RecordNotFound, Mastodon::NotPermittedError
     true