Show release notes in tag list

A release's tag reference is just the name of the tag, not the entire
tag object.

This also fixes the tags index if a tag's message contains non-UTF8 byte
sequences.

CHANGELOG

@@ -21,6 +21,7 @@ v 8.10.2 (unreleased)
   - Fix backup restore. !5459
   - Rescue Rugged::OSError (lock exists) when creating references. !5497
   - Disable MySQL foreign key checks before dropping all tables. !5472
+  - Show release notes in tags list
   - Use project ID in repository cache to prevent stale data from persisting across projects. !5460
   - Ensure relative paths for video are rewritten as we do for images. !5474
   - Ensure current user can retry a build before showing the 'Retry' button. !5476

app/controllers/projects/tags_controller.rb

@@ -10,11 +10,12 @@ class Projects::TagsController < Projects::ApplicationController
     @tags = @repository.tags_sorted_by(@sort)
     @tags = Kaminari.paginate_array(@tags).page(params[:page])
-    @releases = project.releases.where(tag: @tags)
+    @releases = project.releases.where(tag: @tags.map(&:name))
   end
   def show
     @tag = @repository.find_tag(params[:id])
+
     @release = @project.releases.find_or_initialize_by(tag: @tag.name)
     @commit = @repository.commit(@tag.target)
   end

spec/controllers/projects/tags_controller_spec.rb

+require 'spec_helper'
+
+describe Projects::TagsController do
+  let(:project) { create(:project, :public) }
+  let!(:release) { create(:release, project: project) }
+  let!(:invalid_release) { create(:release, project: project, tag: 'does-not-exist') }
+
+  describe 'GET index' do
+    before { get :index, namespace_id: project.namespace.to_param, project_id: project.to_param }
+
+    it 'returns the tags for the page' do
+      expect(assigns(:tags).map(&:name)).to eq(['v1.1.0', 'v1.0.0'])
+    end
+
+    it 'returns releases matching those tags' do
+      expect(assigns(:releases)).to include(release)
+      expect(assigns(:releases)).not_to include(invalid_release)
+    end
+  end
+end