Switch Search Elasticsearch index to use default english stemmer

ee/changelogs/unreleased/277390-global-search-not-finding-result-when-project-search-does.yml

+---
+title: Switch Search Elasticsearch index to use english stemmer
+merge_request: 48518
+author:
+type: fixed

ee/lib/elastic/latest/config.rb

@@ -39,7 +39,7 @@ module Elastic
             analyzer: {
               default: {
                 tokenizer: 'standard',
-                filter: %w(lowercase my_stemmer)
+                filter: %w(lowercase stemmer)
               },
               my_ngram_analyzer: {
                 tokenizer: 'my_ngram_tokenizer',
@@ -62,10 +62,6 @@ module Elastic
               }
             },
             filter: {
-              my_stemmer: {
-                type: 'stemmer',
-                name: 'light_english'
-              },
               code: {
                 type: "pattern_capture",
                 preserve_original: true,

ee/spec/lib/gitlab/elastic/search_results_spec.rb

@@ -204,28 +204,11 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
 
   describe 'issues' do
     let(:scope) { 'issues' }
+    let!(:issue_1) { create(:issue, project: project_1, title: 'Hello world, here I am!', iid: 1) }
+    let!(:issue_2) { create(:issue, project: project_1, title: 'Issue Two', description: 'Hello world, here I am!', iid: 2) }
+    let!(:issue_3) { create(:issue, project: project_2, title: 'Issue Three', iid: 2) }
 
     before do
-      @issue_1 = create(
-        :issue,
-        project: project_1,
-        title: 'Hello world, here I am!',
-        iid: 1
-      )
-      @issue_2 = create(
-        :issue,
-        project: project_1,
-        title: 'Issue Two',
-        description: 'Hello world, here I am!',
-        iid: 2
-      )
-      @issue_3 = create(
-        :issue,
-        project: project_2,
-        title: 'Issue Three',
-        iid: 2
-      )
-
       ensure_elasticsearch_index!
     end
 
@@ -235,7 +218,7 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
       results = described_class.new(user, 'hello world', limit_project_ids)
       issues = results.objects('issues')
 
-      expect(issues).to contain_exactly(@issue_1, @issue_2)
+      expect(issues).to contain_exactly(issue_1, issue_2)
       expect(results.issues_count).to eq 2
     end
 
@@ -250,7 +233,7 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
       results = described_class.new(user, '#2', limit_project_ids, public_and_internal_projects: false)
       issues = results.objects('issues')
 
-      expect(issues).to contain_exactly(@issue_2)
+      expect(issues).to contain_exactly(issue_2)
       expect(results.issues_count).to eq 1
     end
 
@@ -258,7 +241,7 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
       results = described_class.new(user, '2', limit_project_ids, public_and_internal_projects: false)
       issues = results.objects('issues')
 
-      expect(issues).to contain_exactly(@issue_2)
+      expect(issues).to contain_exactly(issue_2)
       expect(results.issues_count).to eq 1
     end
 
@@ -269,6 +252,18 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
       expect(results.issues_count).to eq 0
     end
 
+    it 'handles plural words through algorithmic stemming', :aggregate_failures do
+      issue1 = create(:issue, project: project_1, title: 'remove :title attribute from submit buttons to prevent un-styled tooltips')
+      issue2 = create(:issue, project: project_1, title: 'smarter submit behavior for buttons groups')
+
+      ensure_elasticsearch_index!
+
+      results = described_class.new(user, 'button', limit_project_ids)
+
+      expect(results.objects('issues')).to contain_exactly(issue1, issue2)
+      expect(results.issues_count).to eq 2
+    end
+
     context 'filtering' do
       let!(:project) { create(:project, :public) }
       let!(:closed_result) { create(:issue, :closed, project: project, title: 'foo closed') }
@@ -990,7 +985,7 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
       commits = results.objects('commits')
 
       expect(commits.first.message.downcase).to include("add")
-      expect(results.commits_count).to eq 24
+      expect(results.commits_count).to eq 21
     end
 
     it 'finds commits from public projects only' do
@@ -1000,10 +995,10 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
       ensure_elasticsearch_index!
 
       results = described_class.new(user, 'add', [project_1.id])
-      expect(results.commits_count).to eq 24
+      expect(results.commits_count).to eq 21
 
       results = described_class.new(user, 'add', [project_1.id, project_2.id])
-      expect(results.commits_count).to eq 48
+      expect(results.commits_count).to eq 42
     end
 
     it 'returns zero when commits are not found' do