Add support to group labels prioritization on project level

app/controllers/projects/labels_controller.rb

@@ -12,8 +12,8 @@ class Projects::LabelsController < Projects::ApplicationController
   respond_to :js, :html
 
   def index
-    @prioritized_labels = @available_labels.prioritized
-    @labels = @available_labels.unprioritized.page(params[:page])
+    @prioritized_labels = @available_labels.prioritized(@project)
+    @labels = @available_labels.unprioritized(@project).page(params[:page])
 
     respond_to do |format|
       format.html
@@ -84,11 +84,10 @@ class Projects::LabelsController < Projects::ApplicationController
     respond_to do |format|
       label = @available_labels.find(params[:id])
 
-      if label.update_attribute(:priority, nil)
+      if label.priorities.where(project_id: project).delete_all
         format.json { render json: label }
       else
-        message = label.errors.full_messages.uniq.join('. ')
-        format.json { render json: { message: message }, status: :unprocessable_entity }
+        format.json { head :unprocessable_entity }
       end
     end
   end
@@ -100,7 +99,9 @@ class Projects::LabelsController < Projects::ApplicationController
       params[:label_ids].each_with_index do |label_id, index|
         next unless label_ids.include?(label_id.to_i)
 
-        Label.where(id: label_id).update_all(priority: index)
+        label_priority = LabelPriority.find_or_initialize_by(project_id: @project.id, label_id: label_id)
+        label_priority.priority = index
+        label_priority.save!
       end
     end
 

app/models/label.rb

@@ -32,12 +32,14 @@ class Label < ActiveRecord::Base
   scope :templates, -> { where(template: true) }
   scope :with_title, ->(title) { where(title: title) }
 
-  def self.prioritized
-    where.not(priority: nil).reorder(:priority, :title)
+  def self.prioritized(project)
+    joins(:priorities)
+      .where(label_priorities: { project_id: project })
+      .reorder('label_priorities.priority ASC, labels.title ASC')
   end
 
-  def self.unprioritized
-    where(priority: nil)
+  def self.unprioritized(project)
+    where.not(id: prioritized(project).select(:id))
   end
 
   alias_attribute :name, :title

spec/features/projects/labels/update_prioritization_spec.rb

@@ -35,7 +35,7 @@ feature 'Prioritize labels', feature: true do
     end
 
     scenario 'user can unprioritize a group label', js: true do
-      feature.update(priority: 1)
+      create(:label_priority, project: project, label: feature, priority: 1)
 
       visit namespace_project_labels_path(project.namespace, project)
 
@@ -70,7 +70,7 @@ feature 'Prioritize labels', feature: true do
     end
 
     scenario 'user can unprioritize a project label', js: true do
-      bug.update(priority: 1)
+      create(:label_priority, project: project, label: bug, priority: 1)
 
       visit namespace_project_labels_path(project.namespace, project)
 
@@ -89,8 +89,8 @@ feature 'Prioritize labels', feature: true do
     end
 
     scenario 'user can sort prioritized labels and persist across reloads', js: true do
-      bug.update(priority: 1)
-      feature.update(priority: 2)
+      create(:label_priority, project: project, label: bug, priority: 1)
+      create(:label_priority, project: project, label: feature, priority: 2)
 
       visit namespace_project_labels_path(project.namespace, project)
 

spec/models/label_priority_spec.rb

@@ -9,7 +9,6 @@ describe LabelPriority, models: true do
   describe 'validations' do
     it { is_expected.to validate_presence_of(:project) }
     it { is_expected.to validate_presence_of(:label) }
-    it { is_expected.to validate_presence_of(:priority) }
     it { is_expected.to validate_numericality_of(:priority).only_integer.is_greater_than_or_equal_to(0) }
 
     it 'validates uniqueness of label_id scoped to project_id' do