Merge branch 'dz-nested-groups' into 'master'

Add nested groups support on data level

## What does this MR do?

- [x] Add  `parent_id` field to `Namespace`model. 
- [x] Create new database table `routes` that keeps information about full path to each group or project
- [x] Remove uniq index from `namespaces.path`
- [x] Add uniq index on `routes.path`
- [x] Fill routes table with path data from namespaces and projects
- [x] Change Namespace/Project URL lookup by routes table
- [x] Rename related routes (nested groups, projects) when parent path changes

This is solely backend preparation. UI, Permissions and API support will be added in separate merge request.   
 
## Are there points in the code the reviewer needs to double check?

migrations, Route model, Routable concern

Will require downtime. See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7121#note_19490281 discussion

## Why was this MR needed?

One step further to full nested groups support

## Screenshots (if relevant)

No UI changes in this merge request so far

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added~~
- ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- ~~API support added~~
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/2772

See merge request !7121

6 files changed, 112 insertions, 62 deletions

diff --git a/spec/lib/constraints/group_url_constrainer_spec.rb b/spec/lib/constraints/group_url_constrainer_spec.rb
index 892554f2870..96dacdc5cd2 100644
--- a/spec/lib/constraints/group_url_constrainer_spec.rb
+++ b/spec/lib/constraints/group_url_constrainer_spec.rb
@@ -10,6 +10,13 @@ describe GroupUrlConstrainer, lib: true do
       it { expect(subject.matches?(request)).to be_truthy }
     end
 
+    context 'valid request for nested group' do
+      let!(:nested_group) { create(:group, path: 'nested', parent: group) }
+      let!(:request) { build_request('gitlab/nested') }
+
+      it { expect(subject.matches?(request)).to be_truthy }
+    end
+
     context 'invalid request' do
       let(:request) { build_request('foo') }
 
diff --git a/spec/lib/gitlab/import_export/all_models.yml b/spec/lib/gitlab/import_export/all_models.yml
index 7e00e214c6e..8e1a28f2723 100644
--- a/spec/lib/gitlab/import_export/all_models.yml
+++ b/spec/lib/gitlab/import_export/all_models.yml
@@ -188,6 +188,7 @@ project:
 - project_feature
 - authorized_users
 - project_authorizations
+- route
 award_emoji:
 - awardable
 - user
diff --git a/spec/models/concerns/routable_spec.rb b/spec/models/concerns/routable_spec.rb
new file mode 100644
index 00000000000..0acefc0c1d5
--- /dev/null
+++ b/spec/models/concerns/routable_spec.rb
@@ -0,0 +1,67 @@
+require 'spec_helper'
+
+describe Group, 'Routable' do
+  let!(:group) { create(:group) }
+
+  describe 'Associations' do
+    it { is_expected.to have_one(:route).dependent(:destroy) }
+  end
+
+  describe 'Callbacks' do
+    it 'creates route record on create' do
+      expect(group.route.path).to eq(group.path)
+    end
+
+    it 'updates route record on path change' do
+      group.update_attributes(path: 'wow')
+
+      expect(group.route.path).to eq('wow')
+    end
+
+    it 'ensure route path uniqueness across different objects' do
+      create(:group, parent: group, path: 'xyz')
+      duplicate = build(:project, namespace: group, path: 'xyz')
+
+      expect { duplicate.save! }.to raise_error(ActiveRecord::RecordInvalid, 'Validation failed: Route path has already been taken, Route is invalid')
+    end
+  end
+
+  describe '.find_by_full_path' do
+    let!(:nested_group) { create(:group, parent: group) }
+
+    it { expect(described_class.find_by_full_path(group.to_param)).to eq(group) }
+    it { expect(described_class.find_by_full_path(group.to_param.upcase)).to eq(group) }
+    it { expect(described_class.find_by_full_path(nested_group.to_param)).to eq(nested_group) }
+    it { expect(described_class.find_by_full_path('unknown')).to eq(nil) }
+  end
+
+  describe '.where_paths_in' do
+    context 'without any paths' do
+      it 'returns an empty relation' do
+        expect(described_class.where_paths_in([])).to eq([])
+      end
+    end
+
+    context 'without any valid paths' do
+      it 'returns an empty relation' do
+        expect(described_class.where_paths_in(%w[unknown])).to eq([])
+      end
+    end
+
+    context 'with valid paths' do
+      let!(:nested_group) { create(:group, parent: group) }
+
+      it 'returns the projects matching the paths' do
+        result = described_class.where_paths_in([group.to_param, nested_group.to_param])
+
+        expect(result).to contain_exactly(group, nested_group)
+      end
+
+      it 'returns projects regardless of the casing of paths' do
+        result = described_class.where_paths_in([group.to_param.upcase, nested_group.to_param.upcase])
+
+        expect(result).to contain_exactly(group, nested_group)
+      end
+    end
+  end
+end
diff --git a/spec/models/namespace_spec.rb b/spec/models/namespace_spec.rb
index ba0ed4a3603..7f82e85563b 100644
--- a/spec/models/namespace_spec.rb
+++ b/spec/models/namespace_spec.rb
@@ -124,4 +124,12 @@ describe Namespace, models: true do
       expect(Namespace.clean_path("--%+--valid_*&%name=.git.%.atom.atom.@email.com")).to eq("valid_name")
     end
   end
+
+  describe '#full_path' do
+    let(:group) { create(:group) }
+    let(:nested_group) { create(:group, parent: group) }
+
+    it { expect(group.full_path).to eq(group.path) }
+    it { expect(nested_group.full_path).to eq("#{group.path}/#{nested_group.path}") }
+  end
 end
diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index 4d57330ed1c..21ff238841e 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -478,35 +478,6 @@ describe Project, models: true do
     end
   end
 
-  describe '.find_with_namespace' do
-    context 'with namespace' do
-      before do
-        @group = create :group, name: 'gitlab'
-        @project = create(:project, name: 'gitlabhq', namespace: @group)
-      end
-
-      it { expect(Project.find_with_namespace('gitlab/gitlabhq')).to eq(@project) }
-      it { expect(Project.find_with_namespace('GitLab/GitlabHQ')).to eq(@project) }
-      it { expect(Project.find_with_namespace('gitlab-ci')).to be_nil }
-    end
-
-    context 'when multiple projects using a similar name exist' do
-      let(:group) { create(:group, name: 'gitlab') }
-
-      let!(:project1) do
-        create(:empty_project, name: 'gitlab1', path: 'gitlab', namespace: group)
-      end
-
-      let!(:project2) do
-        create(:empty_project, name: 'gitlab2', path: 'GITLAB', namespace: group)
-      end
-
-      it 'returns the row where the path matches literally' do
-        expect(Project.find_with_namespace('gitlab/GITLAB')).to eq(project2)
-      end
-    end
-  end
-
   describe '#to_param' do
     context 'with namespace' do
       before do
@@ -1548,39 +1519,6 @@ describe Project, models: true do
     end
   end
 
-  describe '.where_paths_in' do
-    context 'without any paths' do
-      it 'returns an empty relation' do
-        expect(Project.where_paths_in([])).to eq([])
-      end
-    end
-
-    context 'without any valid paths' do
-      it 'returns an empty relation' do
-        expect(Project.where_paths_in(%w[foo])).to eq([])
-      end
-    end
-
-    context 'with valid paths' do
-      let!(:project1) { create(:project) }
-      let!(:project2) { create(:project) }
-
-      it 'returns the projects matching the paths' do
-        projects = Project.where_paths_in([project1.path_with_namespace,
-                                           project2.path_with_namespace])
-
-        expect(projects).to contain_exactly(project1, project2)
-      end
-
-      it 'returns projects regardless of the casing of paths' do
-        projects = Project.where_paths_in([project1.path_with_namespace.upcase,
-                                           project2.path_with_namespace.upcase])
-
-        expect(projects).to contain_exactly(project1, project2)
-      end
-    end
-  end
-
   describe 'change_head' do
     let(:project) { create(:project) }
 
diff --git a/spec/models/route_spec.rb b/spec/models/route_spec.rb
new file mode 100644
index 00000000000..6f491fdf9a0
--- /dev/null
+++ b/spec/models/route_spec.rb
@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+describe Route, models: true do
+  let!(:group) { create(:group) }
+  let!(:route) { group.route }
+
+  describe 'relationships' do
+    it { is_expected.to belong_to(:source) }
+  end
+
+  describe 'validations' do
+    it { is_expected.to validate_presence_of(:source) }
+    it { is_expected.to validate_presence_of(:path) }
+    it { is_expected.to validate_uniqueness_of(:path) }
+  end
+
+  describe '#rename_children' do
+    let!(:nested_group) { create(:group, path: "test", parent: group) }
+    let!(:deep_nested_group) { create(:group, path: "foo", parent: nested_group) }
+
+    it "updates children routes with new path" do
+      route.update_attributes(path: 'bar')
+
+      expect(described_class.exists?(path: 'bar')).to be_truthy
+      expect(described_class.exists?(path: 'bar/test')).to be_truthy
+      expect(described_class.exists?(path: 'bar/test/foo')).to be_truthy
+    end
+  end
+end