Display commit sha value in the footer.

Gemfile

@@ -11,6 +11,7 @@ gem 'rubocop', '>= 1.31.0'
 gem 'gettext'
 gem 'prism', '>= 0.30.0'
 gem 'webrick'
+gem 'git'
 
 platforms :ruby do
   if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('3.2')

lib/rdoc/generator/template/aliki/_footer.rhtml

@@ -18,6 +18,9 @@
     <p>
       Generated by <a href="https://ruby.github.io/rdoc/">RDoc <%= RDoc::VERSION %></a>
       using the Aliki theme by <a href="http://st0012.dev">Stan Lo</a>
+      <% if @options.git_commit_sha %>
+      Generated with commit <%= @options.git_commit_sha %>
+      <% end %>
     </p>
   </div>
 </footer>

lib/rdoc/options.rb

@@ -393,6 +393,10 @@ class RDoc::Options
 
   attr_accessor :footer_content
 
+  ##
+  # Git hash value
+  attr_accessor :git_commit_sha
+
   def initialize(loaded_options = nil) # :nodoc:
     init_ivars
     override loaded_options if loaded_options
@@ -450,6 +454,7 @@ def init_ivars # :nodoc:
     @file_path_prefix = nil
     @canonical_root = nil
     @footer_content = nil
+    @git_commit_sha = nil
   end
 
   def init_with(map) # :nodoc:

lib/rdoc/rdoc.rb

@@ -468,6 +468,8 @@ def document(options)
 
     @options.default_title = "RDoc Documentation"
 
+    @options.git_commit_sha = detect_git_commit
+
     @store.complete @options.visibility
 
     @stats.coverage_level = @options.coverage_report
@@ -494,6 +496,13 @@ def document(options)
     exit @stats.fully_documented? if @options.coverage_report
   end
 
+  def detect_git_commit
+    require "git"
+    Git.open(Dir.pwd).object("HEAD").sha
+  rescue StandardError
+    nil
+  end
+
   ##
   # Generates documentation for +file_info+ (from #parse_files) into the
   # output dir using the generator selected

test/rdoc/rdoc_options_test.rb

@@ -91,6 +91,7 @@ def test_to_yaml
       'file_path_prefix' => nil,
       'canonical_root' => nil,
       'footer_content' => nil,
+      'git_commit_sha' => nil,
     }
 
     assert_equal expected, coder