Make searching issues/MRs by IID even easier

Prior to this change you were required to prepend your search with `#`
or `!` (like an Issue/MR link) to trigger the search by IID behaviour.
This changes things so that it's even simpler to search by IID. As long
as the input is just a number we'll ensure that the IID field is
included in search query. This also won't prevent you from searching for
the number as part of an issue title or description since we also query
those fields but we give higher weight to the IID so exact IID matches
should appear as the first result.

This MR also includes some refactoring to improve the tests.
Specifically some of the tests for searching by IID were passing by
accident before. It also refactors them to use `contain_exactly` since
this makes them more concise.

ee/changelogs/unreleased/search-issue-and-mr-id.yml

+---
+title: Make searching issues/MRs by IID even easier
+merge_request: 40467
+author:
+type: added

ee/lib/elastic/latest/issue_class_proxy.rb

@@ -8,7 +8,14 @@ module Elastic
           if query =~ /#(\d+)\z/
             iid_query_hash(Regexp.last_match(1))
           else
-            basic_query_hash(%w(title^2 description), query)
+            fields = %w(title^2 description)
+
+            # We can only allow searching the iid field if the query is
+            # just a number, otherwise Elasticsearch will error since this
+            # field is type integer.
+            fields << "iid^3" if query =~ /\A\d+\z/
+
+            basic_query_hash(fields, query)
           end
 
         options[:features] = 'issues'

ee/lib/elastic/latest/merge_request_class_proxy.rb

@@ -8,7 +8,14 @@ module Elastic
           if query =~ /\!(\d+)\z/
             iid_query_hash(Regexp.last_match(1))
           else
-            basic_query_hash(%w(title^2 description), query)
+            fields = %w(title^2 description)
+
+            # We can only allow searching the iid field if the query is
+            # just a number, otherwise Elasticsearch will error since this
+            # field is type integer.
+            fields << "iid^3" if query =~ /\A\d+\z/
+
+            basic_query_hash(fields, query)
           end
 
         options[:features] = 'merge_requests'

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

@@ -118,14 +118,14 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
       @issue_2 = create(
         :issue,
         project: project_1,
-        title: 'Issue 2',
+        title: 'Issue Two',
         description: 'Hello world, here I am!',
         iid: 2
       )
       @issue_3 = create(
         :issue,
         project: project_2,
-        title: 'Issue 3',
+        title: 'Issue Three',
         iid: 2
       )
 
@@ -138,9 +138,7 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
       results = described_class.new(user, 'hello world', limit_projects)
       issues = results.objects('issues')
 
-      expect(issues).to include @issue_1
-      expect(issues).to include @issue_2
-      expect(issues).not_to include @issue_3
+      expect(issues).to contain_exactly(@issue_1, @issue_2)
       expect(results.issues_count).to eq 2
     end
 
@@ -155,9 +153,15 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
       results = described_class.new(user, '#2', limit_projects, public_and_internal_projects: false)
       issues = results.objects('issues')
 
-      expect(issues).not_to include @issue_1
-      expect(issues).to include @issue_2
-      expect(issues).not_to include @issue_3
+      expect(issues).to contain_exactly(@issue_2)
+      expect(results.issues_count).to eq 1
+    end
+
+    it 'can also find an issue by iid without the prefixed #' do
+      results = described_class.new(user, '2', limit_projects, public_and_internal_projects: false)
+      issues = results.objects('issues')
+
+      expect(issues).to contain_exactly(@issue_2)
       expect(results.issues_count).to eq 1
     end
 
@@ -421,7 +425,7 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
         :conflict,
         source_project: project_1,
         target_project: project_1,
-        title: 'Merge Request 2',
+        title: 'Merge Request Two',
         description: 'Hello world, here I am!',
         iid: 2
       )
@@ -429,7 +433,7 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
         :merge_request,
         source_project: project_2,
         target_project: project_2,
-        title: 'Merge Request 3',
+        title: 'Merge Request Three',
         iid: 2
       )
 
@@ -439,12 +443,10 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
     it_behaves_like 'a paginated object', 'merge_requests'
 
     it 'lists found merge requests' do
-      results = described_class.new(user, 'hello world', limit_projects)
+      results = described_class.new(user, 'hello world', limit_projects, public_and_internal_projects: false)
       merge_requests = results.objects('merge_requests')
 
-      expect(merge_requests).to include @merge_request_1
-      expect(merge_requests).to include @merge_request_2
-      expect(merge_requests).not_to include @merge_request_3
+      expect(merge_requests).to contain_exactly(@merge_request_1, @merge_request_2)
       expect(results.merge_requests_count).to eq 2
     end
 
@@ -456,12 +458,18 @@ RSpec.describe Gitlab::Elastic::SearchResults, :elastic, :sidekiq_might_not_need
     end
 
     it 'lists merge request when search by a valid iid' do
-      results = described_class.new(user, '#2', limit_projects)
+      results = described_class.new(user, '!2', limit_projects, public_and_internal_projects: false)
+      merge_requests = results.objects('merge_requests')
+
+      expect(merge_requests).to contain_exactly(@merge_request_2)
+      expect(results.merge_requests_count).to eq 1
+    end
+
+    it 'can also find an issue by iid without the prefixed !' do
+      results = described_class.new(user, '2', limit_projects, public_and_internal_projects: false)
       merge_requests = results.objects('merge_requests')
 
-      expect(merge_requests).not_to include @merge_request_1
-      expect(merge_requests).to include @merge_request_2
-      expect(merge_requests).not_to include @merge_request_3
+      expect(merge_requests).to contain_exactly(@merge_request_2)
       expect(results.merge_requests_count).to eq 1
     end