Fixed merge request search page

Fixed query in issuable concern file.
Added tests accordingly.

app/models/concerns/issuable.rb

@@ -128,7 +128,7 @@ module Issuable
     end
 
     scope :joins_milestone_releases, -> do
-      joins("JOIN milestone_releases ON issues.milestone_id = milestone_releases.milestone_id
+      joins("JOIN milestone_releases ON #{table_name}.milestone_id = milestone_releases.milestone_id
              JOIN releases ON milestone_releases.release_id = releases.id").distinct
     end
 

spec/models/concerns/issuable_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe Issuable do
+  include ProjectForksHelper
+
   let(:issuable_class) { Issue }
   let(:issue) { create(:issue, title: 'An issue', description: 'A description') }
   let(:user) { create(:user) }
@@ -855,6 +857,7 @@ describe Issuable do
 
   describe 'release scopes' do
     let_it_be(:project) { create(:project) }
+    let(:forked_project) { fork_project(project) }
 
     let_it_be(:release_1) { create(:release, tag: 'v1.0', project: project) }
     let_it_be(:release_2) { create(:release, tag: 'v2.0', project: project) }
@@ -875,52 +878,65 @@ describe Issuable do
     let_it_be(:issue_5) { create(:issue, milestone: milestone_6, project: project) }
     let_it_be(:issue_6) { create(:issue, project: project) }
 
-    let_it_be(:items) { Issue.all }
+    let(:mr_1) { create(:merge_request, milestone: milestone_1, target_project: project, source_project: project) }
+    let(:mr_2) { create(:merge_request, milestone: milestone_3, target_project: project, source_project: forked_project) }
+    let(:mr_3) { create(:merge_request, target_project: project, source_project: project) }
+
+    let_it_be(:issue_items) { Issue.all }
+    let(:mr_items) { MergeRequest.all }
 
     describe '#without_release' do
-      it 'returns the issues not tied to any milestone and the ones tied to milestone with no release' do
-        expect(items.without_release).to contain_exactly(issue_5, issue_6)
+      it 'returns the issues or mrs not tied to any milestone and the ones tied to milestone with no release' do
+        expect(issue_items.without_release).to contain_exactly(issue_5, issue_6)
+        expect(mr_items.without_release).to contain_exactly(mr_3)
       end
     end
 
     describe '#any_release' do
-      it 'returns all issues tied to a release' do
-        expect(items.any_release).to contain_exactly(issue_1, issue_2, issue_3, issue_4)
+      it 'returns all issues or all mrs tied to a release' do
+        expect(issue_items.any_release).to contain_exactly(issue_1, issue_2, issue_3, issue_4)
+        expect(mr_items.any_release).to contain_exactly(mr_1, mr_2)
       end
     end
 
     describe '#with_release' do
-      it 'returns the issues tied a specfic release' do
-        expect(items.with_release('v1.0', project.id)).to contain_exactly(issue_1, issue_2, issue_3)
+      it 'returns the issues tied to a specfic release' do
+        expect(issue_items.with_release('v1.0', project.id)).to contain_exactly(issue_1, issue_2, issue_3)
+      end
+
+      it 'returns the mrs tied to a specific release' do
+        expect(mr_items.with_release('v1.0', project.id)).to contain_exactly(mr_1)
       end
 
       context 'when a release has a milestone with one issue and another one with no issue' do
         it 'returns that one issue' do
-          expect(items.with_release('v2.0', project.id)).to contain_exactly(issue_3)
+          expect(issue_items.with_release('v2.0', project.id)).to contain_exactly(issue_3)
         end
 
         context 'when the milestone with no issue is added as a filter' do
           it 'returns an empty list' do
-            expect(items.with_release('v2.0', project.id).with_milestone('m3')).to be_empty
+            expect(issue_items.with_release('v2.0', project.id).with_milestone('m3')).to be_empty
           end
         end
 
         context 'when the milestone with the issue is added as a filter' do
           it 'returns this issue' do
-            expect(items.with_release('v2.0', project.id).with_milestone('m2')).to contain_exactly(issue_3)
+            expect(issue_items.with_release('v2.0', project.id).with_milestone('m2')).to contain_exactly(issue_3)
           end
         end
       end
 
-      context 'when there is no issue under a specific release' do
-        it 'returns no issue' do
-          expect(items.with_release('v4.0', project.id)).to be_empty
+      context 'when there is no issue or mr under a specific release' do
+        it 'returns no issue or no mr' do
+          expect(issue_items.with_release('v4.0', project.id)).to be_empty
+          expect(mr_items.with_release('v4.0', project.id)).to be_empty
         end
       end
 
       context 'when a non-existent release tag is passed in' do
-        it 'returns no issue' do
-          expect(items.with_release('v999.0', project.id)).to be_empty
+        it 'returns no issue or no mr' do
+          expect(issue_items.with_release('v999.0', project.id)).to be_empty
+          expect(mr_items.with_release('v999.0', project.id)).to be_empty
         end
       end
     end