Remove switch to basic search link

This was originally implemented as a back up because we were concerned
about the reliability of Elasticsearch. We assumed it would be safe to
add this link just in case our Elasticsearch experience was consistently
bad.

But it turned out that we forgot to ever turn the feature flag on and
our Elasticsearch has been quite robust anyway. As such we may as well
remove the feature now.

We still keep the hidden feature where the user can manually add a
`basic_search=true` to the URL to get the basic search functionality
because this is still useful for diagnostic purposes but we don't need
to provide a link to this as it's not something most people will need to
use.

app/views/search/_results.html.haml

@@ -2,7 +2,6 @@
   = render partial: "search/results/filters"
   = render partial: "search/results/empty"
   = render_if_exists 'shared/promotions/promote_advanced_search'
-  = render_if_exists 'search/form_revert_to_basic'
 - else
   .row-content-block.d-md-flex.text-left.align-items-center
     - unless @search_objects.is_a?(Kaminari::PaginatableWithoutCount)

ee/app/helpers/ee/search_helper.rb

@@ -60,23 +60,6 @@ module EE
       Truncato.truncate(search_highlight[issue.id].description.first, count_tags: false, count_tail: false, max_length: 200).html_safe
     end
 
-    def revert_to_basic_search_filter_url
-      search_params = params
-        .permit(::SearchHelper::SEARCH_PERMITTED_PARAMS)
-        .merge(basic_search: true)
-
-      search_path(search_params)
-    end
-
-    def show_switch_to_basic_search?(search_service)
-      return false unless ::Feature.enabled?(:switch_to_basic_search, default_enabled: false)
-      return false unless search_service.use_elasticsearch?
-
-      return true if @project
-
-      search_service.scope.in?(SWITCH_TO_BASIC_SEARCHABLE_TABS)
-    end
-
     private
 
     def search_multiple_assignees?(type)

ee/app/views/search/_form_revert_to_basic.html.haml

-- if show_switch_to_basic_search?(search_service)
-  - begin_link = '<a href="%{url}">'.html_safe % { url: revert_to_basic_search_filter_url }
-  - end_link = '</a>'.html_safe
-  %p.text-center
-    = _('You can try again using %{begin_link}basic search%{end_link}').html_safe % { begin_link: begin_link, end_link: end_link }

ee/config/feature_flags/development/switch_to_basic_search.yml

----
-name: switch_to_basic_search
-introduced_by_url: 
-rollout_issue_url: 
-group: 
-type: development
-default_enabled: false

ee/spec/features/search/elastic/global_search_spec.rb

@@ -230,39 +230,6 @@ RSpec.describe 'Global elastic search', :elastic, :sidekiq_inline do
       expect(page).to have_content('Users 0')
     end
   end
-
-  context 'when no results are returned' do
-    it 'allows basic search without Elasticsearch' do
-      visit dashboard_projects_path
-
-      # Disable sidekiq to ensure it does not end up in the index
-      Sidekiq::Testing.disable! do
-        create(:project, namespace: user.namespace, name: 'Will not be found but searchable')
-      end
-
-      submit_search('searchable')
-
-      expect(page).not_to have_content('Will not be found')
-
-      # Since there are no results you have the option to instead use basic
-      # search
-      click_link 'basic search'
-
-      # Project is found now that we are using basic search
-      expect(page).to have_content('Will not be found')
-    end
-
-    context 'when performing Commits search' do
-      it 'does not allow basic search' do
-        visit dashboard_projects_path
-
-        submit_search('project')
-        select_search_scope('Commits')
-
-        expect(page).not_to have_link('basic search')
-      end
-    end
-  end
 end
 
 RSpec.describe 'Global elastic search redactions', :elastic do

ee/spec/helpers/search_helper_spec.rb

@@ -121,48 +121,4 @@ RSpec.describe SearchHelper do
       it_behaves_like 'returns old message'
     end
   end
-
-  describe '#show_switch_to_basic_search?' do
-    let(:use_elasticsearch) { true }
-    let(:scope) { 'commits' }
-    let(:search_service) { instance_double(Search::GlobalService, use_elasticsearch?: use_elasticsearch, scope: scope) }
-
-    subject { show_switch_to_basic_search?(search_service) }
-
-    before do
-      stub_feature_flags(switch_to_basic_search: true)
-    end
-
-    context 'when :switch_to_basic_search feature is disabled' do
-      before do
-        stub_feature_flags(switch_to_basic_search: false)
-      end
-
-      it { is_expected.to eq(false) }
-    end
-
-    context 'when not currently using elasticsearch' do
-      let(:use_elasticsearch) { false }
-
-      it { is_expected.to eq(false) }
-    end
-
-    context 'when project scope' do
-      before do
-        @project = create(:project)
-      end
-
-      it { is_expected.to eq(true) }
-    end
-
-    context 'when commits tab' do
-      it { is_expected.to eq(false) }
-    end
-
-    context 'when issues tab' do
-      let(:scope) { 'issues' }
-
-      it { is_expected.to eq(true) }
-    end
-  end
 end

locale/gitlab.pot

@@ -29195,9 +29195,6 @@ msgstr ""
 msgid "You can test your .gitlab-ci.yml in %{linkStart}CI Lint%{linkEnd}."
 msgstr ""
 
-msgid "You can try again using %{begin_link}basic search%{end_link}"
-msgstr ""
-
 msgid "You cannot access the raw file. Please wait a minute."
 msgstr ""