Initialize History lazily, make it work without Readline

lib/pry/history.rb

@@ -2,7 +2,6 @@ class Pry
   # The History class is responsible for maintaining the user's input history,
   # both internally and within Readline.
   class History
-
     attr_accessor :loader, :saver, :pusher, :clearer
 
     # @return [Fixnum] Number of lines in history when Pry first loaded.
@@ -17,10 +16,18 @@ class Pry
 
     # Assign the default methods for loading, saving, pushing, and clearing.
     def restore_default_behavior
-      @loader  = method(:read_from_file)
-      @saver   = method(:save_to_file)
-      @pusher  = method(:push_to_readline)
-      @clearer = method(:clear_readline)
+      Pry.config.input # force Readline to load if applicable
+
+      @loader = method(:read_from_file)
+      @saver  = method(:save_to_file)
+
+      if defined?(Readline)
+        @pusher  = method(:push_to_readline)
+        @clearer = method(:clear_readline)
+      else
+        @pusher  = proc { }
+        @clearer = proc { }
+      end
     end
 
     # Load the input history using `History.loader`.

lib/pry/pry_class.rb

@@ -10,11 +10,11 @@ class Pry
     attr_accessor :current_line
     attr_accessor :line_buffer
     attr_accessor :eval_path
-    attr_accessor :history
     attr_accessor :cli
     attr_accessor :quiet
     attr_accessor :last_internal_error
     attr_accessor :config
+    attr_writer :history
 
     def_delegators :@plugin_manager, :plugins, :load_plugins, :locate_plugins
 
@@ -28,6 +28,10 @@ class Pry
     def prompt
       config.prompt
     end
+
+    def history
+      @history ||= History.new
+    end
   end
 
   def self.main
@@ -276,7 +280,6 @@ Readline version #{Readline::VERSION} detected - will not auto_resize! correctly
   # Basic initialization.
   def self.init
     @plugin_manager ||= PluginManager.new
-    self.history ||= History.new
     reset_defaults
     locate_plugins
   end

spec/helper.rb

@@ -15,9 +15,6 @@ require 'spec_helpers/bacon'
 require 'spec_helpers/mock_pry'
 require 'spec_helpers/repl_tester'
 
-# FIXME: temporary until history is fixed to not need Readline
-require 'readline'
-
 class Module
   public :remove_const
   public :remove_method