Search feature: redirects to commit page if query is commit sha and only commit found

See !8028 and #24833

app/controllers/search_controller.rb

@@ -45,6 +45,8 @@ class SearchController < ApplicationController
       end
     @search_objects = @search_results.objects(@scope, params[:page])
+
+    check_single_commit_result
   end
   def autocomplete
@@ -59,4 +61,16 @@ class SearchController < ApplicationController
     render json: search_autocomplete_opts(term).to_json
   end
+
+  private
+
+  def check_single_commit_result
+    if @search_results.single_commit_result?
+      only_commit = @search_results.objects('commits').first
+      query = params[:search].strip.downcase
+      found_by_commit_sha = Commit.valid_hash?(query) && only_commit.sha.start_with?(query)
+
+      redirect_to namespace_project_commit_path(@project.namespace, @project, only_commit) if found_by_commit_sha
+    end
+  end
 end

changelogs/unreleased/redirect-to-commit-when-only-commit-found.yml

+---
+title: 'Search feature: redirects to commit page if query is commit sha and only commit
+  found'
+merge_request: 8028
+author: YarNayar

lib/gitlab/project_search_results.rb

@@ -71,6 +71,14 @@ module Gitlab
       )
     end
+    def single_commit_result?
+      commits_count == 1 && total_result_count == 1
+    end
+
+    def total_result_count
+      issues_count + merge_requests_count + milestones_count + notes_count + blobs_count + wiki_blobs_count + commits_count
+    end
+
     private
     def blobs
@@ -122,7 +130,7 @@ module Gitlab
       commits = find_commits_by_message(query)
       commit_by_sha = find_commit_by_sha(query)
-      commits << commit_by_sha if commit_by_sha && !commits.include?(commit_by_sha)
+      commits |= [commit_by_sha] if commit_by_sha
       commits
     end

lib/gitlab/search_results.rb

@@ -43,6 +43,10 @@ module Gitlab
       @milestones_count ||= milestones.count
     end
+    def single_commit_result?
+      false
+    end
+
     private
     def projects

spec/features/search_spec.rb

@@ -217,6 +217,31 @@ describe "Search", feature: true  do
       visit search_path(project_id: project.id)
     end
+    it 'redirects to commit page when search by sha and only commit found' do
+      fill_in 'search', with: '6d394385cf567f80a8fd85055db1ab4c5295806f'
+
+      click_button 'Search'
+
+      expect(page).to have_current_path(namespace_project_commit_path(project.namespace, project, '6d394385cf567f80a8fd85055db1ab4c5295806f'))
+    end
+
+    it 'redirects to single commit regardless of query case' do
+      fill_in 'search', with: '6D394385cf'
+
+      click_button 'Search'
+
+      expect(page).to have_current_path(namespace_project_commit_path(project.namespace, project, '6d394385cf567f80a8fd85055db1ab4c5295806f'))
+    end
+
+    it 'holds on /search page when the only commit is found by message' do
+      create_commit('Message referencing another sha: "deadbeef" ', project, user, 'master')
+
+      fill_in 'search', with: 'deadbeef'
+      click_button 'Search'
+
+      expect(page).to have_current_path('/search', only_path: true)
+    end
+
     it 'shows multiple matching commits' do
       fill_in 'search', with: 'See merge request'