Merge branch 'issues-show-performance' into 'master'

Improve performance of viewing individual issues

This MR does two things:

1. `Issue#related_branches` no longer performs Git operations that aren't needed
2. The output of `Repository#exists?` is now cached and flushed properly

Combined these two changes should further cut down the amount of Git operations performed when viewing individual issues (and possibly other pages).

See merge request !3296

6 files changed, 102 insertions, 8 deletions

diff --git a/spec/controllers/projects/issues_controller_spec.rb b/spec/controllers/projects/issues_controller_spec.rb
index 2cd81231144..a49bd8960ee 100644
--- a/spec/controllers/projects/issues_controller_spec.rb
+++ b/spec/controllers/projects/issues_controller_spec.rb
@@ -2,7 +2,7 @@ require('spec_helper')
 
 describe Projects::IssuesController do
   describe "GET #index" do
-    let(:project) { create(:project) }
+    let(:project) { create(:project_empty_repo) }
     let(:user) { create(:user) }
     let(:issue) { create(:issue, project: project) }
 
@@ -41,7 +41,7 @@ describe Projects::IssuesController do
   end
 
   describe 'Confidential Issues' do
-    let(:project) { create(:empty_project, :public) }
+    let(:project) { create(:project_empty_repo, :public) }
     let(:assignee) { create(:assignee) }
     let(:author) { create(:user) }
     let(:non_member) { create(:user) }
diff --git a/spec/models/issue_spec.rb b/spec/models/issue_spec.rb
index 05e4233243d..8334545b759 100644
--- a/spec/models/issue_spec.rb
+++ b/spec/models/issue_spec.rb
@@ -183,9 +183,9 @@ describe Issue, models: true do
   describe '#related_branches' do
     it "selects the right branches" do
       allow(subject.project.repository).to receive(:branch_names).
-                                    and_return(["mpempe", "#{subject.iid}mepmep", subject.to_branch_name])
+        and_return(["mpempe", "#{subject.iid}mepmep", subject.to_branch_name])
 
-      expect(subject.related_branches).to eq [subject.to_branch_name]
+      expect(subject.related_branches).to eq([subject.to_branch_name])
     end
   end
 
diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index b8b9a455b83..624022c1dda 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -720,4 +720,45 @@ describe Project, models: true do
       expect(described_class.search_by_title('KITTENS')).to eq([project])
     end
   end
+
+  describe '#create_repository' do
+    let(:project) { create(:project) }
+    let(:shell) { Gitlab::Shell.new }
+
+    before do
+      allow(project).to receive(:gitlab_shell).and_return(shell)
+    end
+
+    context 'using a regular repository' do
+      it 'creates the repository' do
+        expect(shell).to receive(:add_repository).
+          with(project.path_with_namespace).
+          and_return(true)
+
+        expect(project.repository).to receive(:after_create)
+
+        expect(project.create_repository).to eq(true)
+      end
+
+      it 'adds an error if the repository could not be created' do
+        expect(shell).to receive(:add_repository).
+          with(project.path_with_namespace).
+          and_return(false)
+
+        expect(project.repository).not_to receive(:after_create)
+
+        expect(project.create_repository).to eq(false)
+        expect(project.errors).not_to be_empty
+      end
+    end
+
+    context 'using a forked repository' do
+      it 'does nothing' do
+        expect(project).to receive(:forked?).and_return(true)
+        expect(shell).not_to receive(:add_repository)
+
+        project.create_repository
+      end
+    end
+  end
 end
diff --git a/spec/models/project_wiki_spec.rb b/spec/models/project_wiki_spec.rb
index a2085df5bcd..532e3f013fd 100644
--- a/spec/models/project_wiki_spec.rb
+++ b/spec/models/project_wiki_spec.rb
@@ -244,6 +244,18 @@ describe ProjectWiki, models: true do
     end
   end
 
+  describe '#create_repo!' do
+    it 'creates a repository' do
+      expect(subject).to receive(:init_repo).
+        with(subject.path_with_namespace).
+        and_return(true)
+
+      expect(subject.repository).to receive(:after_create)
+
+      expect(subject.create_repo!).to be_an_instance_of(Gollum::Wiki)
+    end
+  end
+
   private
 
   def create_temp_repo(path)
diff --git a/spec/models/repository_spec.rb b/spec/models/repository_spec.rb
index a57229a4fdf..7eac70ae948 100644
--- a/spec/models/repository_spec.rb
+++ b/spec/models/repository_spec.rb
@@ -537,6 +537,12 @@ describe Repository, models: true do
 
         repository.before_delete
       end
+
+      it 'flushes the exists cache' do
+        expect(repository).to receive(:expire_exists_cache)
+
+        repository.before_delete
+      end
     end
 
     describe 'when a repository exists' do
@@ -593,6 +599,12 @@ describe Repository, models: true do
 
       repository.after_import
     end
+
+    it 'flushes the exists cache' do
+      expect(repository).to receive(:expire_exists_cache)
+
+      repository.after_import
+    end
   end
 
   describe '#after_push_commit' do
@@ -619,6 +631,14 @@ describe Repository, models: true do
     end
   end
 
+  describe '#after_create' do
+    it 'flushes the exists cache' do
+      expect(repository).to receive(:expire_exists_cache)
+
+      repository.after_create
+    end
+  end
+
   describe "#main_language" do
     it 'shows the main language of the project' do
       expect(repository.main_language).to eq("Ruby")
@@ -781,6 +801,16 @@ describe Repository, models: true do
     end
   end
 
+  describe '#expire_exists_cache' do
+    let(:cache) { repository.send(:cache) }
+
+    it 'expires the cache' do
+      expect(cache).to receive(:expire).with(:exists?)
+
+      repository.expire_exists_cache
+    end
+  end
+
   describe '#build_cache' do
     let(:cache) { repository.send(:cache) }
 
diff --git a/spec/workers/repository_fork_worker_spec.rb b/spec/workers/repository_fork_worker_spec.rb
index 172537474ee..4ef05eb29d2 100644
--- a/spec/workers/repository_fork_worker_spec.rb
+++ b/spec/workers/repository_fork_worker_spec.rb
@@ -3,12 +3,17 @@ require 'spec_helper'
 describe RepositoryForkWorker do
   let(:project) { create(:project) }
   let(:fork_project) { create(:project, forked_from_project: project) }
+  let(:shell) { Gitlab::Shell.new }
 
   subject { RepositoryForkWorker.new }
 
+  before do
+    allow(subject).to receive(:gitlab_shell).and_return(shell)
+  end
+
   describe "#perform" do
     it "creates a new repository from a fork" do
-      expect_any_instance_of(Gitlab::Shell).to receive(:fork_repository).with(
+      expect(shell).to receive(:fork_repository).with(
         project.path_with_namespace,
         fork_project.namespace.path
       ).and_return(true)
@@ -19,20 +24,26 @@ describe RepositoryForkWorker do
         fork_project.namespace.path)
     end
 
-    it 'flushes the empty caches' do
-      expect_any_instance_of(Gitlab::Shell).to receive(:fork_repository).
+    it 'flushes various caches' do
+      expect(shell).to receive(:fork_repository).
         with(project.path_with_namespace, fork_project.namespace.path).
         and_return(true)
 
       expect_any_instance_of(Repository).to receive(:expire_emptiness_caches).
         and_call_original
 
+      expect_any_instance_of(Repository).to receive(:expire_exists_cache).
+        and_call_original
+
       subject.perform(project.id, project.path_with_namespace,
                       fork_project.namespace.path)
     end
 
     it "handles bad fork" do
-      expect_any_instance_of(Gitlab::Shell).to receive(:fork_repository).and_return(false)
+      expect(shell).to receive(:fork_repository).and_return(false)
+
+      expect(subject.logger).to receive(:error)
+
       subject.perform(
         project.id,
         project.path_with_namespace,