Merge pull request #1117 from pry/lazy-readline

lazy load readline through Proc defined on Pry::Config::Default.

.travis.yml

@@ -8,6 +8,10 @@ rvm:
   - jruby-19mode
   - jruby-head
 
+script:
+  - rake spec
+  - bundle exec bacon spec/isolation/readline_spec.rb
+
 matrix:
   allow_failures:
     - rvm: ruby-head

CHANGELOG.md

@@ -21,7 +21,8 @@
 * User can whitelist objects whose inspect output should appear in prompt (#885)
   * See `Pry.config.prompt_safe_objects`
 * `whereami` is now aliased to `@`
-* improve configuration(Pry.config) to lazy-load default configuration values. (#1096)
+* default configuration(Pry.config) lazy loads its values. (#1096)
+* require of 'readline' is delayed until Pry.start() has been called for the first time. (#1117)
 
 #### Bug fixes, etc.
 * `binding.pry` inside `.pryrc` file now works, with some limitations (@richo / #1118)

Rakefile

@@ -42,7 +42,7 @@ task :test do
     if explicit_list = ENV['run']
       explicit_list.split(',')
     else
-      Dir['spec/**/*_spec.rb'].shuffle!
+      (Dir['spec/**/*_spec.rb'] - Dir["spec/isolation/*_spec.rb"]).shuffle!
     end
   run_specs paths
 end

lib/pry.rb

@@ -132,19 +132,13 @@ require 'rbconfig'
 require 'tempfile'
 require 'pathname'
 
-begin
-  require 'readline'
-rescue LoadError
-  warn "You're running a version of ruby with no Readline support"
-  warn "Please `gem install rb-readline` or recompile ruby --with-readline."
-  exit!
-end
 
 if Pry::Helpers::BaseHelpers.jruby?
   begin
     require 'ffi'
   rescue LoadError
-    warn "Need to `gem install ffi`"
+    # TODO: Why do we need this?
+    warn "For a better Pry experience on JRuby, please `gem install ffi`."
   end
 end
 
@@ -155,7 +149,8 @@ if Pry::Helpers::BaseHelpers.windows? && !Pry::Helpers::BaseHelpers.windows_ansi
     # only fail on jruby (where win32console doesn't work).
     # Instead we'll recommend ansicon, which does.
   rescue LoadError
-    warn "For a better pry experience, please use ansicon: https://github.com/adoxa/ansicon"
+    warn "For a better Pry experience on Windows, please use ansicon:"
+    warn "   http://adoxa.3eeweb.com/ansicon/"
   end
 end
 

lib/pry/config/default.rb

@@ -2,7 +2,7 @@ class Pry::Config::Default
   include Pry::Config::Behavior
 
   default = {
-    :input                  => proc { Readline },
+    :input                  => proc { lazy_readline },
     :output                 => proc { $stdout },
     :commands               => proc { Pry::Commands },
     :prompt_name            => proc { Pry::DEFAULT_PROMPT_NAME },
@@ -35,13 +35,7 @@ class Pry::Config::Default
     :extra_sticky_locals    => proc { {} },
     :command_completer      => proc { proc { Pry.commands.commands.keys } },
     :file_completer         => proc { proc { Dir["."] } },
-    :completer => proc {
+    :completer              => proc { lazy_completer }
-      if defined?(Bond) && Readline::VERSION !~ /editline/i
-        Pry::BondCompleter.start
-      else
-        Pry::InputCompleter.start
-      end
-    }
   }
 
   def initialize
@@ -54,13 +48,14 @@ class Pry::Config::Default
   default.each do |key, value|
     define_method(key) do
       if default[key].equal?(value)
-        default[key] = value.call
+        default[key] = instance_eval(&value)
       end
       default[key]
     end
   end
 
 private
+
   # TODO:
   # all of this configure_* stuff is a relic of old code.
   # we should try move this code to being command-local.
@@ -101,4 +96,28 @@ private
       history.should_load = false
     end
   end
+
+  def lazy_readline
+    require 'readline'
+    Readline
+  rescue LoadError
+    warn "Sorry, you can't use Pry without Readline or a compatible library."
+    warn "Possible solutions:"
+    warn " * Rebuild Ruby with Readline support using `--with-readline`"
+    warn " * Use the rb-readline gem, which is a pure-Ruby port of Readline"
+    warn " * Use the pry-coolline gem, a pure-ruby alternative to Readline"
+    raise
+  end
+
+  def lazy_completer
+    if defined?(Bond) && !is_editline?(input)
+      Pry::BondCompleter.start
+    else
+      Pry::InputCompleter.start
+    end
+  end
+
+  def is_editline?(input)
+    defined?(input::VERSION) && input::VERSION =~ /editline/i
+  end
 end

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)
+      Pry.config.input # force Readline to load if applicable
-      @saver   = method(:save_to_file)
+
-      @pusher  = method(:push_to_readline)
+      @loader = method(:read_from_file)
-      @clearer = method(:clear_readline)
+      @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
@@ -233,15 +237,22 @@ class Pry
   end
 
   def self.auto_resize!
-    ver = Readline::VERSION
+    Pry.config.input # by default, load Readline
-    if ver[/edit/i]
+
+    if !defined?(Readline) || Pry.config.input != Readline
+      warn "Sorry, you must be using Readline for Pry.auto_resize! to work."
+      return
+    end
+
+    if Readline::VERSION =~ /edit/i
       warn <<-EOT
-Readline version #{ver} detected - will not auto_resize! correctly.
+Readline version #{Readline::VERSION} detected - will not auto_resize! correctly.
   For the fix, use GNU Readline instead:
   https://github.com/guard/guard/wiki/Add-proper-Readline-support-to-Ruby-on-Mac-OS-X
       EOT
       return
     end
+
     trap :WINCH do
       begin
         Readline.set_screen_size(*Terminal.size!)
@@ -269,7 +280,6 @@ Readline version #{ver} detected - will not auto_resize! correctly.
   # Basic initialization.
   def self.init
     @plugin_manager ||= PluginManager.new
-    self.history ||= History.new
     reset_defaults
     locate_plugins
   end

lib/pry/repl.rb

@@ -179,7 +179,7 @@ class Pry
           end
         end
 
-        if input == Readline
+        if defined?(Readline) and input == Readline
           input_readline(current_prompt, false) # false since we'll add it manually
         elsif defined? Coolline and input.is_a? Coolline
           input_readline(current_prompt)

lib/pry/terminal.rb

@@ -54,7 +54,7 @@ class Pry::Terminal
     end
 
     def screen_size_according_to_readline
-      if Readline.respond_to?(:get_screen_size)
+      if defined?(Readline) && Readline.respond_to?(:get_screen_size)
         size = Readline.get_screen_size
         size if nonzero_column?(size)
       end

spec/completion_spec.rb

@@ -6,16 +6,22 @@ def completer_test(bind, pry=nil, assert_flag=true)
   return proc {|*symbols| symbols.each(&test) }
 end
 
-if defined?(Bond) && Readline::VERSION !~ /editline/i
+describe 'Bond-based completion' do
-  describe 'bond-based completion' do
+  before do
-    it 'should pull in Bond by default' do
+    @local = Pry::Config.new Pry::Config::Default.new
-      Pry.config.completer.should == Pry::BondCompleter
+    @local.completer
+  end
+
+  it "should use Bond if it's available" do
+    if defined?(Bond) && defined?(Readline) && Readline::VERSION !~ /editline/i
+      @local.completer.should == Pry::BondCompleter
+    else
+      @local.completer.should == Pry::InputCompleter
     end
   end
 end
 
 describe Pry::InputCompleter do
-
   before do
     # The AMQP gem has some classes like this:
     #  pry(main)> AMQP::Protocol::Test::ContentOk.name

spec/isolation/readline_spec.rb

@@ -0,0 +1,17 @@
+require "bundler/setup"
+require "bacon"
+describe "Readline" do
+  describe "on require of 'pry'" do
+    it "is not made available" do
+      require('pry').should.be.true
+      defined?(Readline).should.be.nil
+    end
+  end
+
+  describe "on invoke of 'pry'" do
+    it "is made available" do
+      Pry.start self, input: StringIO.new("exit-all\n"), output: StringIO.new
+      defined?(Readline).should == "constant"
+    end
+  end
+end