Add a flash messages when an issue resolving discussions is created

app/controllers/projects/issues_controller.rb

@@ -106,7 +106,13 @@ class Projects::IssuesController < Projects::ApplicationController
       discussion_to_resolve: params[:discussion_to_resolve]
     )
 
-    @issue = Issues::CreateService.new(project, current_user, create_params).execute
+    service = Issues::CreateService.new(project, current_user, create_params)
+    @issue = service.execute
+
+    if service.discussions_to_resolve.any? && service.discussions_to_resolve.all?(&:resolved?)
+      resolve_count = service.discussions_to_resolve.size
+      flash[:notice] = "Resolved #{resolve_count} #{'discussion'.pluralize(resolve_count)}."
+    end
 
     respond_to do |format|
       format.html do

spec/controllers/projects/issues_controller_spec.rb

@@ -495,6 +495,20 @@ describe Projects::IssuesController do
         expect(discussion.resolved?).to eq(true)
       end
 
+      it 'sets a flash message' do
+        post_issue(title: 'Hello')
+
+        expect(flash[:notice]).to eq('Resolved 1 discussion.')
+      end
+
+      it 'pluralizes the flash message when resolving multiple discussions' do
+        create(:diff_note_on_merge_request, noteable: merge_request, project: project, line_number: 15)
+
+        post_issue(title: 'Hello')
+
+        expect(flash[:notice]).to eq('Resolved 2 discussions.')
+      end
+
       it "resolves a single discussion" do
         post_issue(other_params: { discussion_to_resolve: discussion.id })
         discussion.first_note.reload

spec/support/features/resolving_discussions_in_issues_shared_examples.rb

@@ -23,6 +23,16 @@ shared_examples 'creating an issue for a discussion' do
     expect(discussion.resolved?).to eq(true)
   end
 
+  it 'shows a flash messaage after resolving a discussion' do
+    click_button 'Submit issue'
+
+    page.within '.flash-notice' do
+      # Only check for the word 'Resolved' since the spec might have resolved
+      # multiple discussions
+      expect(page).to have_content('Resolved')
+    end
+  end
+
   it 'has a hidden field for the merge request' do
     merge_request_field = find('#merge_request_for_resolving_discussions', visible: false)