WIP: allow adding and removing labels in bulk

app/controllers/projects/issues_controller.rb

@@ -217,7 +217,9 @@ class Projects::IssuesController < Projects::ApplicationController
       :assignee_id,
       :milestone_id,
       :state_event,
-      label_ids: []
+      label_ids: [],
+      add_label_ids: [],
+      remove_label_ids: []
     )
   end
 end

app/services/issuable_base_service.rb

@@ -45,6 +45,8 @@ class IssuableBaseService < BaseService
 
     unless can?(current_user, ability, project)
       params.delete(:milestone_id)
+      params.delete(:add_label_ids)
+      params.delete(:remove_label_ids)
       params.delete(:label_ids)
       params.delete(:assignee_id)
     end
@@ -67,10 +69,35 @@ class IssuableBaseService < BaseService
   end
 
   def filter_labels
-    return if params[:label_ids].to_a.empty?
+    if params[:add_label_ids].present? || params[:remove_label_ids].present?
+      params.delete(:label_ids)
+
+      filter_labels_by_name([:add_label_ids, :remove_label_ids])
+    else
+      filter_labels_by_name([:label_ids])
+    end
+  end
+
+  def filter_labels_by_name(keys)
+    keys.each do |key|
+      return if params[key].to_a.empty?
+
+      params[key] = project.labels.where(id: params[key]).pluck(:id)
+    end
+  end
+
+  def update_issuable(issuable, attributes)
+    issuable.with_transaction_returning_status do
+      add_label_ids = attributes.delete(:add_label_ids)
+      remove_label_ids = attributes.delete(:remove_label_ids)
 
-    params[:label_ids] =
-      project.labels.where(id: params[:label_ids]).pluck(:id)
+      issuable.label_ids |= add_label_ids if add_label_ids
+      issuable.label_ids -= remove_label_ids if remove_label_ids
+
+      issuable.assign_attributes(attributes)
+
+      issuable.save
+    end
   end
 
   def update(issuable)
@@ -78,7 +105,7 @@ class IssuableBaseService < BaseService
     filter_params
     old_labels = issuable.labels.to_a
 
-    if params.present? && issuable.update_attributes(params.merge(updated_by: current_user))
+    if params.present? && update_issuable(issuable, params.merge(updated_by: current_user))
       issuable.reset_events_cache
       handle_common_system_notes(issuable, old_labels: old_labels)
       handle_changes(issuable, old_labels: old_labels)

app/services/issues/bulk_update_service.rb

@@ -4,9 +4,9 @@ module Issues
       issues_ids   = params.delete(:issues_ids).split(",")
       issue_params = params
 
-      issue_params.delete(:state_event)   unless issue_params[:state_event].present?
-      issue_params.delete(:milestone_id)  unless issue_params[:milestone_id].present?
-      issue_params.delete(:assignee_id)   unless issue_params[:assignee_id].present?
+      [:state_event, :milestone_id, :assignee_id, :label_ids, :add_label_ids, :remove_label_ids].each do |key|
+        issue_params.delete(key) unless issue_params[key].present?
+      end
 
       issues = Issue.where(id: issues_ids)
       issues.each do |issue|