Cache RDoc::RI::Driver.new (#911)

* Cache RDoc::RI::Driver.new to improve performance and to avoid flaky test

* Insert sleep to fix flaky rendering test that renders document dialog

lib/irb/input-method.rb

@@ -308,6 +308,20 @@ def retrieve_doc_namespace(matched)
       @completor.doc_namespace(preposing, matched, postposing, bind: bind)
     end
 
+    def rdoc_ri_driver
+      return @rdoc_ri_driver if defined?(@rdoc_ri_driver)
+
+      begin
+        require 'rdoc'
+      rescue LoadError
+        @rdoc_ri_driver = nil
+      else
+        options = {}
+        options[:extra_doc_dirs] = IRB.conf[:EXTRA_DOC_DIRS] unless IRB.conf[:EXTRA_DOC_DIRS].empty?
+        @rdoc_ri_driver = RDoc::RI::Driver.new(options)
+      end
+    end
+
     def show_doc_dialog_proc
       input_method = self # self is changed in the lambda below.
       ->() {
@@ -331,9 +345,7 @@ def show_doc_dialog_proc
 
         show_easter_egg = name&.match?(/\ARubyVM/) && !ENV['RUBY_YES_I_AM_NOT_A_NORMAL_USER']
 
-        options = {}
-        options[:extra_doc_dirs] = IRB.conf[:EXTRA_DOC_DIRS] unless IRB.conf[:EXTRA_DOC_DIRS].empty?
-        driver = RDoc::RI::Driver.new(options)
+        driver = input_method.rdoc_ri_driver
 
         if key.match?(dialog.name)
           if show_easter_egg
@@ -421,12 +433,9 @@ def show_doc_dialog_proc
       }
     end
 
-    def display_document(matched, driver: nil)
-      begin
-        require 'rdoc'
-      rescue LoadError
-        return
-      end
+    def display_document(matched)
+      driver = rdoc_ri_driver
+      return unless driver
 
       if matched =~ /\A(?:::)?RubyVM/ and not ENV['RUBY_YES_I_AM_NOT_A_NORMAL_USER']
         IRB.__send__(:easter_egg)
@@ -436,7 +445,6 @@ def display_document(matched, driver: nil)
       namespace = retrieve_doc_namespace(matched)
       return unless namespace
 
-      driver ||= RDoc::RI::Driver.new
       if namespace.is_a?(Array)
         out = RDoc::Markup::Document.new
         namespace.each do |m|

test/irb/test_input_method.rb

@@ -88,17 +88,18 @@ def setup
       @driver = RDoc::RI::Driver.new(use_stdout: true)
     end
 
-    def display_document(target, bind)
+    def display_document(target, bind, driver = nil)
       input_method = IRB::RelineInputMethod.new(IRB::RegexpCompletor.new)
+      input_method.instance_variable_set(:@rdoc_ri_driver, driver) if driver
       input_method.instance_variable_set(:@completion_params, ['', target, '', bind])
-      input_method.display_document(target, driver: @driver)
+      input_method.display_document(target)
     end
 
     def test_perfectly_matched_namespace_triggers_document_display
       omit unless has_rdoc_content?
 
       out, err = capture_output do
-        display_document("String", binding)
+        display_document("String", binding, @driver)
       end
 
       assert_empty(err)
@@ -109,7 +110,7 @@ def test_perfectly_matched_namespace_triggers_document_display
     def test_perfectly_matched_multiple_namespaces_triggers_document_display
       result = nil
       out, err = capture_output do
-        result = display_document("{}.nil?", binding)
+        result = display_document("{}.nil?", binding, @driver)
       end
 
       assert_empty(err)
@@ -131,7 +132,7 @@ def test_perfectly_matched_multiple_namespaces_triggers_document_display
     def test_not_matched_namespace_triggers_nothing
       result = nil
       out, err = capture_output do
-        result = display_document("Stri", binding)
+        result = display_document("Stri", binding, @driver)
       end
 
       assert_empty(err)
@@ -156,7 +157,7 @@ def test_perfect_matching_stops_without_rdoc
     def test_perfect_matching_handles_nil_namespace
       out, err = capture_output do
         # symbol literal has `nil` doc namespace so it's a good test subject
-        assert_nil(display_document(":aiueo", binding))
+        assert_nil(display_document(":aiueo", binding, @driver))
       end
 
       assert_empty(err)

test/irb/yamatanooroti/test_rendering.rb

@@ -256,9 +256,9 @@ def test_autocomplete_with_multiple_doc_namespaces
     start_terminal(3, 50, %W{ruby -I#{@pwd}/lib #{@pwd}/exe/irb}, startup_message: 'start IRB')
     write("{}.__id_")
     write("\C-i")
+    sleep 0.2
     close
     screen = result.join("\n").sub(/\n*\z/, "\n")
-    # This assertion passes whether showdoc dialog completed or not.
     assert_match(/start\ IRB\nirb\(main\):001> {}\.__id__\n                }\.__id__(?:Press )?/, screen)
   end
 
@@ -278,6 +278,7 @@ def test_autocomplete_with_showdoc_in_gaps_on_narrow_screen_right
     start_terminal(4, 19, %W{ruby -I#{@pwd}/lib #{@pwd}/exe/irb}, startup_message: 'start IRB')
     write("IR")
     write("\C-i")
+    sleep 0.2
     close
 
     # This is because on macOS we display different shortcut for displaying the full doc
@@ -315,6 +316,7 @@ def test_autocomplete_with_showdoc_in_gaps_on_narrow_screen_left
     start_terminal(4, 12, %W{ruby -I#{@pwd}/lib #{@pwd}/exe/irb}, startup_message: 'start IRB')
     write("IR")
     write("\C-i")
+    sleep 0.2
     close
     assert_screen(<<~EOC)
       start IRB