Improve labels validation and expose error messages

app/models/concerns/issuable.rb

@@ -138,6 +138,10 @@ module Issuable
     labels.order('title ASC').pluck(:title)
   end
+  def remove_labels
+    labels.delete_all
+  end
+
   def add_labels_by_names(label_names)
     label_names.each do |label_name|
       label = project.labels.create_with(

app/models/label.rb

@@ -6,14 +6,14 @@ class Label < ActiveRecord::Base
   has_many :issues, through: :label_links, source: :target, source_type: 'Issue'
   validates :color,
-            format: { with: /\A\#[0-9A-Fa-f]{6}+\Z/ },
+            format: { with: /\A#[0-9A-Fa-f]{6}\Z/ },
             allow_blank: false
   validates :project, presence: true
   # Don't allow '?', '&', and ',' for label titles
   validates :title,
             presence: true,
-            format: { with: /\A[^&\?,&]*\z/ },
+            format: { with: /\A[^&\?,&]+\z/ },
             uniqueness: { scope: :project_id }
   scope :order_by_name, -> { reorder("labels.title ASC") }

lib/api/helpers.rb

@@ -114,17 +114,21 @@ module API
     # Helper method for validating all labels against its names
     def validate_label_params(params)
+      errors = {}
+
       if params[:labels].present?
         params[:labels].split(',').each do |label_name|
           label = user_project.labels.create_with(
             color: Label::DEFAULT_COLOR).find_or_initialize_by(
               title: label_name.strip)
+
           if label.invalid?
-            return true
+            errors[label.title] = label.errors
           end
         end
       end
-      false
+
+      errors
     end
     # error helpers

lib/api/issues.rb

@@ -52,8 +52,8 @@ module API
         attrs = attributes_for_keys [:title, :description, :assignee_id, :milestone_id]
         # Validate label names in advance
-        if validate_label_params(params)
-          return render_api_error!('Label names invalid', 405)
+        if (errors = validate_label_params(params)).any?
+          render_api_error!({ labels: errors }, 400)
         end
         issue = ::Issues::CreateService.new(user_project, current_user, attrs).execute
@@ -90,8 +90,8 @@ module API
         attrs = attributes_for_keys [:title, :description, :assignee_id, :milestone_id, :state_event]
         # Validate label names in advance
-        if validate_label_params(params)
-          return render_api_error!('Label names invalid', 405)
+        if (errors = validate_label_params(params)).any?
+          render_api_error!({ labels: errors }, 400)
         end
         issue = ::Issues::UpdateService.new(user_project, current_user, attrs).execute(issue)
@@ -99,7 +99,8 @@ module API
         if issue.valid?
           # Find or create labels and attach to issue. Labels are valid because
           # we already checked its name, so there can't be an error here
-          if params[:labels].present?
+          unless params[:labels].nil?
+            issue.remove_labels
             # Create and add labels to the new created issue
             issue.add_labels_by_names(params[:labels].split(','))
           end

spec/requests/api/issues_spec.rb

@@ -73,12 +73,12 @@ describe API::API, api: true  do
       response.status.should == 400
     end
-    it 'should return 405 on invalid label names' do
+    it 'should return 400 on invalid label names' do
       post api("/projects/#{project.id}/issues", user),
            title: 'new issue',
            labels: 'label, ?'
-      response.status.should == 405
-      json_response['message'].should == 'Label names invalid'
+      response.status.should == 400
+      json_response['message']['labels']['?']['title'].should == ['is invalid']
     end
   end
@@ -97,12 +97,56 @@ describe API::API, api: true  do
       response.status.should == 404
     end
-    it 'should return 405 on invalid label names' do
+    it 'should return 400 on invalid label names' do
       put api("/projects/#{project.id}/issues/#{issue.id}", user),
           title: 'updated title',
           labels: 'label, ?'
-      response.status.should == 405
-      json_response['message'].should == 'Label names invalid'
+      response.status.should == 400
+      json_response['message']['labels']['?']['title'].should == ['is invalid']
+    end
+  end
+
+  describe 'PUT /projects/:id/issues/:issue_id to update labels' do
+    let!(:label) { create(:label, title: 'dummy', project: project) }
+    let!(:label_link) { create(:label_link, label: label, target: issue) }
+
+    it 'should not update labels if not present' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          title: 'updated title'
+      response.status.should == 200
+      json_response['labels'].should == [label.title]
+    end
+
+    it 'should remove all labels' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          labels: ''
+      response.status.should == 200
+      json_response['labels'].should == []
+    end
+
+    it 'should update labels' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          labels: 'foo,bar'
+      response.status.should == 200
+      json_response['labels'].should include 'foo'
+      json_response['labels'].should include 'bar'
+    end
+
+    it 'should return 400 on invalid label names' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          labels: 'label, ?'
+      response.status.should == 400
+      json_response['message']['labels']['?']['title'].should == ['is invalid']
+    end
+
+    it 'should allow special label names' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          labels: 'label:foo, label-bar,label_bar,label/bar'
+      response.status.should == 200
+      json_response['labels'].should include 'label:foo'
+      json_response['labels'].should include 'label-bar'
+      json_response['labels'].should include 'label_bar'
+      json_response['labels'].should include 'label/bar'
     end
   end

spec/requests/api/labels_spec.rb

@@ -50,6 +50,14 @@ describe API::API, api: true  do
       json_response['message'].should == 'Color is invalid'
     end
+    it 'should return 400 for too long color code' do
+      post api("/projects/#{project.id}/labels", user),
+           name: 'Foo',
+           color: '#FFAAFFFF'
+      response.status.should == 400
+      json_response['message'].should == 'Color is invalid'
+    end
+
     it 'should return 400 for invalid name' do
       post api("/projects/#{project.id}/labels", user),
            name: '?',
@@ -147,5 +155,13 @@ describe API::API, api: true  do
       response.status.should == 400
       json_response['message'].should == 'Color is invalid'
     end
+
+    it 'should return 400 for too long color code' do
+      post api("/projects/#{project.id}/labels", user),
+           name: 'Foo',
+           color: '#FFAAFFFF'
+      response.status.should == 400
+      json_response['message'].should == 'Color is invalid'
+    end
   end
 end