Restore plugin autoloading as deprecated opt-in

lib/pry.rb

@@ -13,6 +13,7 @@
 
 require 'pry/basic_object'
 require 'pry/prompt'
+require 'pry/plugins'
 require 'pry/code_object'
 require 'pry/exceptions'
 require 'pry/hooks'

lib/pry/cli.rb

@@ -35,6 +35,15 @@ def add_options(&block)
         self
       end
 
+      # TODO: Remove add_plugin_options when removing plugin auto-loading
+      # Bring in options defined in plugins
+      def add_plugin_options
+        Pry::Warning.warn "Pry.plugins is deprecated and will be removed entirely"
+        Pry.plugins.values.each(&:load_cli_options)
+
+        self
+      end
+
       # Add a block responsible for processing parsed options.
       def add_option_processor(&block)
         self.option_processors ||= []
@@ -117,6 +126,17 @@ def start(opts)
   end
 end
 
+# TODO: Remove enable-plugins when removing plugin auto-loading
+# Bring in options defined by plugins
+Pry::Slop.new do
+  on "enable-plugins" do
+    Pry.config.should_load_plugins = true
+  end
+end.parse(ARGV.dup)
+
+# TODO: Remove add_plugin_options when removing plugin auto-loading
+Pry::CLI.add_plugin_options if Pry.config.should_load_plugins
+
 # The default Pry command line options (before plugin options are included)
 Pry::CLI.add_options do
   banner(
@@ -162,6 +182,11 @@ def start(opts)
     warn "The --no-plugins option is deprecated and has no effect"
   end
 
+  on :p, "enable-plugins", "Opt-in to auto loading of plugins." do
+    warn "The --enable-plugins option is deprecated"
+    Pry.config.should_load_plugins = true
+  end
+
   on "plugins", "List installed plugins." do
     puts "Installed Plugins:"
     puts "--"

lib/pry/config.rb

@@ -73,6 +73,10 @@ class Config
     # @return [Boolean] whether the local ./.pryrc should be loaded
     attribute :should_load_local_rc
 
+    # TODO: Remove should_load_plugins when removing plugin auto-loading
+    # @return [Boolean]
+    attribute :should_load_plugins
+
     # @return [Boolean] whether to load files specified with the -r flag
     attribute :should_load_requires
 
@@ -193,6 +197,7 @@ def initialize
         output_prefix: '=> ',
         requires: [],
         should_load_requires: true,
+        should_load_plugins: false,
         windows_console_warning: true,
         control_d_handler: Pry::ControlDHandler.method(:default),
         memory_size: 100,

lib/pry/plugins.rb

@@ -0,0 +1,139 @@
+# frozen_string_literal: true
+
+require 'ostruct'
+
+class Pry
+  class PluginManager
+    PRY_PLUGIN_PREFIX = /^pry-/.freeze
+
+    # Placeholder when no associated gem found, displays warning
+    class NoPlugin
+      def initialize(name)
+        @name = name
+      end
+
+      def method_missing(*)
+        warn "Warning: The plugin '#{@name}' was not found! (no gem found)"
+        super
+      end
+
+      def respond_to_missing?(*)
+        false
+      end
+    end
+
+    class Plugin
+      attr_accessor :name, :gem_name, :enabled, :spec, :active
+
+      def initialize(name, gem_name, spec, enabled)
+        @name = name
+        @gem_name = gem_name
+        @enabled = enabled
+        @spec = spec
+      end
+
+      # Disable a plugin. (prevents plugin from being loaded, cannot
+      # disable an already activated plugin)
+      def disable!
+        self.enabled = false
+      end
+
+      # Enable a plugin. (does not load it immediately but puts on
+      # 'white list' to be loaded)
+      def enable!
+        self.enabled = true
+      end
+
+      # Load the Command line options defined by this plugin (if they exist)
+      def load_cli_options
+        cli_options_file = File.join(spec.full_gem_path, "lib/#{spec.name}/cli.rb")
+        return unless File.exist?(cli_options_file)
+
+        if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new("2.4.4")
+          cli_options_file = File.realpath(cli_options_file)
+        end
+        require cli_options_file
+      end
+
+      # Activate the plugin (require the gem - enables/loads the
+      # plugin immediately at point of call, even if plugin is
+      # disabled)
+      # Does not reload plugin if it's already active.
+      def activate!
+        # Create the configuration object for the plugin.
+        Pry.config.send("#{gem_name.tr('-', '_')}=", OpenStruct.new)
+
+        begin
+          require gem_name unless active?
+        rescue LoadError => e
+          warn "Found plugin #{gem_name}, but could not require '#{gem_name}'"
+          warn e
+        rescue StandardError => e
+          warn "require '#{gem_name}' # Failed, saying: #{e}"
+        end
+
+        self.active = true
+        self.enabled = true
+      end
+
+      alias active? active
+      alias enabled? enabled
+
+      def supported?
+        pry_version = Gem::Version.new(VERSION)
+        spec.dependencies.each do |dependency|
+          if dependency.name == "pry"
+            return dependency.requirement.satisfied_by?(pry_version)
+          end
+        end
+        true
+      end
+    end
+
+    def initialize
+      @plugins = []
+    end
+
+    # Find all installed Pry plugins and store them in an internal array.
+    def locate_plugins
+      gem_list.each do |gem|
+        next if gem.name !~ PRY_PLUGIN_PREFIX
+
+        plugin_name = gem.name.split('-', 2).last
+        plugin = Plugin.new(plugin_name, gem.name, gem, false)
+        @plugins << plugin.tap(&:enable!) if plugin.supported? && !plugin_located?(plugin)
+      end
+      @plugins
+    end
+
+    # @return [Hash] A hash with all plugin names (minus the 'pry-') as
+    #   keys and Plugin objects as values.
+    def plugins
+      h = Hash.new { |_, key| NoPlugin.new(key) }
+      @plugins.each do |plugin|
+        h[plugin.name] = plugin
+      end
+      h
+    end
+
+    # Require all enabled plugins, disabled plugins are skipped.
+    def load_plugins
+      @plugins.each do |plugin|
+        plugin.activate! if plugin.enabled?
+      end
+    end
+
+    private
+
+    def plugin_located?(plugin)
+      @plugins.any? { |existing| existing.gem_name == plugin.gem_name }
+    end
+
+    def gem_list
+      Gem.refresh
+      return Gem::Specification if Gem::Specification.respond_to?(:each)
+
+      Gem.source_index.find_name('')
+    end
+  end
+end

lib/pry/pry_class.rb

@@ -24,6 +24,9 @@ class << self
     attr_accessor :last_internal_error
     attr_accessor :config
 
+    # TODO: Remove def_delegators :@plugin_manager when removing plugin auto-loading
+    def_delegators :@plugin_manager, :plugins, :load_plugins, :locate_plugins
+
     def_delegators(
       :@config, :input, :input=, :output, :output=, :commands,
       :commands=, :print, :print=, :exception_handler, :exception_handler=,
@@ -140,6 +143,8 @@ def self.final_session_setup
     return if @session_finalized
 
     @session_finalized = true
+    # TODO: Remove load_plugins when removing plugin auto-loading
+    load_plugins if Pry.config.should_load_plugins
     load_requires if Pry.config.should_load_requires
     load_history if Pry.config.history_load
     load_traps if Pry.config.should_trap_interrupts
@@ -330,7 +335,13 @@ def self.reset_defaults
 
   # Basic initialization.
   def self.init
+    # TODO: Remove PluginManager when removing plugin auto-loading
+    @plugin_manager ||= PluginManager.new
     reset_defaults
+    if Pry.config.should_load_plugins # rubocop:disable Style/GuardClause
+      # TODO: Remove locate_plugins when removing plugin auto-loading
+      locate_plugins
+    end
   end
 
   # Return a `Binding` object for `target` or return `target` if it is

spec/cli_spec.rb

@@ -41,6 +41,21 @@
     end
   end
 
+  describe ".add_plugin_options" do
+    it "returns self" do
+      expect(described_class.add_plugin_options).to eq(described_class)
+    end
+
+    it "loads cli options of plugins" do
+      plugin_mock = double
+      expect(plugin_mock).to receive(:load_cli_options)
+      plugins = { 'pry-testplugin' => plugin_mock }
+      expect(Pry).to receive(:plugins).and_return(plugins)
+
+      described_class.add_plugin_options
+    end
+  end
+
   describe ".add_option_processor" do
     it "returns self" do
       expect(described_class.add_option_processor {}).to eq(described_class)

spec/config_spec.rb

@@ -28,6 +28,7 @@
   specify { expect(subject.output_prefix).to be_a(String) }
   specify { expect(subject.requires).to be_an(Array) }
   specify { expect(subject.should_load_requires).to be(true).or be(false) }
+  specify { expect(subject.should_load_plugins).to be(true).or be(false) }
   specify { expect(subject.windows_console_warning).to be(true).or be(false) }
   specify { expect(subject.control_d_handler).to respond_to(:call) }
   specify { expect(subject.memory_size).to be_a(Numeric) }