Fix Error 500 when creating global milestones with Unicode characters

Two issues:

1. The constraints in the resources were incorrect. Here's what it was before:
```
group_milestone  GET /groups/:group_id/milestones/:id(.:format)  groups/milestones#show {:id=>/[a-zA-Z.0-9_\-]+(?<!\.atom)/, :group_id=>/[a-zA-Z.0-9_\-]+(?<!\.atom)/}
```

In this case, id is actually the title of the milestone, which can be anything at the moment.

After:

```
group_milestone  GET /groups/:group_id/milestones/:id(.:format)  groups/milestones#show {:id=>/[^\/]+/, :group_id=>/[a-zA-Z.0-9_\-]+(?<!\.atom)/}
```

2. `parameterize` would strip all Unicode characters, leaving a blank string. Rails would report something like:

ActionView::Template::Error (No route matches {:action=>"show", :controller=>"groups/milestones", :group_id=>#<Group id: 48, name: "ops-dev", path: "ops-dev", owner_id: nil, created_at: "2015-11-15 08:55:30", updated_at: "2015-12-02 06:23:26", type: "Group", description: "", avatar: "sha1.c71e73d51af1865c1bbbf6208e10044d46c9bb93.png", public: false>, :id=>"", :title=>"肯定不是中文的问题"} missing required keys: [:id]):

This change uses the babosa library to create a better slug, which surprisingly
isn't actually used by the global milestone controllers. Instead, they use the
title passed as a query string for some reason.

Closes https://github.com/gitlabhq/gitlabhq/issues/9881

Fix constraints

CHANGELOG

@@ -14,6 +14,7 @@ v 8.3.0 (unreleased)
 
 v 8.2.3
   - Fix application settings cache not expiring after changes (Stan Hu)
+  - Fix Error 500s when creating global milestones with Unicode characters (Stan Hu)
 
 v 8.2.2
   - Fix 404 in redirection after removing a project (Stan Hu)

Gemfile

@@ -171,6 +171,7 @@ gem "underscore-rails", "~> 1.4.4"
 
 # Sanitize user input
 gem "sanitize", '~> 2.0'
+gem 'babosa', '~> 1.0.2'
 
 # Protect against bruteforcing
 gem "rack-attack", '~> 4.3.0'

Gemfile.lock

@@ -73,6 +73,7 @@ GEM
       descendants_tracker (~> 0.0.4)
       ice_nine (~> 0.11.0)
       thread_safe (~> 0.3, >= 0.3.1)
+    babosa (1.0.2)
     bcrypt (3.1.10)
     benchmark-ips (2.3.0)
     better_errors (1.0.1)
@@ -823,6 +824,7 @@ DEPENDENCIES
   asciidoctor (~> 1.5.2)
   attr_encrypted (~> 1.3.4)
   awesome_print (~> 1.2.0)
+  babosa (~> 1.0.2)
   benchmark-ips
   better_errors (~> 1.0.1)
   binding_of_caller (~> 0.7.2)

app/controllers/groups/milestones_controller.rb

@@ -46,7 +46,7 @@ class Groups::MilestonesController < Groups::ApplicationController
   end
 
   def milestone_path(title)
-    group_milestone_path(@group, title.parameterize, title: title)
+    group_milestone_path(@group, title.to_slug.to_s, title: title)
   end
 
   def projects

app/models/global_milestone.rb

@@ -16,7 +16,7 @@ class GlobalMilestone
   end
 
   def safe_title
-    @title.parameterize
+    @title.to_slug.to_s
   end
 
   def projects

config/routes.rb

@@ -368,7 +368,7 @@ Rails.application.routes.draw do
       end
 
       resource :avatar, only: [:destroy]
-      resources :milestones, only: [:index, :show, :update, :new, :create]
+      resources :milestones, constraints: { id: /[^\/]+/ }, only: [:index, :show, :update, :new, :create]
     end
   end
 

spec/controllers/groups/milestones_controller_spec.rb

@@ -0,0 +1,27 @@
+require 'spec_helper'
+
+describe Groups::MilestonesController do
+  let(:group) { create(:group) }
+  let(:project) { create(:project, group: group) }
+  let(:project2) { create(:empty_project, group: group) }
+  let(:user)    { create(:user) }
+  let(:title) { '肯定不是中文的问题' }
+
+  before do
+    sign_in(user)
+    group.add_owner(user)
+    project.team << [user, :master]
+    controller.instance_variable_set(:@group, group)
+  end
+
+  describe "#create" do
+    it "should create group milestone with Chinese title" do
+      post :create,
+           group_id: group.id,
+           milestone: { project_ids: [project.id, project2.id], title: title }
+
+      expect(response).to redirect_to(group_milestone_path(group, title.to_slug.to_s, title: title))
+      expect(Milestone.where(title: title).count).to eq(2)
+    end
+  end
+end