Merge branch 'finding-multiple-projects-by-paths' into 'master'

Add Project.where_paths_in

In https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4410 I'm working on reducing the SQL queries needed to render Markdown. One reason for the large amount of queries is executing a large number of queries needed to find projects and related data. Basically `Project.find_with_namespace` is called in a loop and then any relations have to be retrieved separately.

By using `Project.where_paths_in` we can work around this by doing something like:

```ruby
project_paths = [...] # populated by some method
projects = Project.where_paths_in(project_paths).includes(:namespace, ...)
```

Ref: https://gitlab.com/gitlab-org/gitlab-ce/issues/18042

See merge request !4535

1 files changed, 33 insertions, 0 deletions

diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index b6f36d3481e..f3590f72cfe 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -922,4 +922,37 @@ describe Project, models: true do
       it { is_expected.to be_falsey }
     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
 end