1 files changed, 53 insertions, 0 deletions
diff --git a/lib/bundler/plugin/dsl.rb b/lib/bundler/plugin/dsl.rb
new file mode 100644
index 0000000000..4bfc8437e0
--- /dev/null
+++ b/lib/bundler/plugin/dsl.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+module Bundler
+  module Plugin
+    # Dsl to parse the Gemfile looking for plugins to install
+    class DSL < Bundler::Dsl
+      class PluginGemfileError < PluginError; end
+      alias_method :_gem, :gem # To use for plugin installation as gem
+
+      # So that we don't have to override all there methods to dummy ones
+      # explicitly.
+      # They will be handled by method_missing
+      [:gemspec, :gem, :path, :install_if, :platforms, :env].each {|m| undef_method m }
+
+      # This lists the plugins that was added automatically and not specified by
+      # the user.
+      #
+      # When we encounter :type attribute with a source block, we add a plugin
+      # by name bundler-source-<type> to list of plugins to be installed.
+      #
+      # These plugins are optional and are not installed when there is conflict
+      # with any other plugin.
+      attr_reader :inferred_plugins
+
+      def initialize
+        super
+        @sources = Plugin::SourceList.new
+        @inferred_plugins = [] # The source plugins inferred from :type
+      end
+
+      def plugin(name, *args)
+        _gem(name, *args)
+      end
+
+      def method_missing(name, *args)
+        raise PluginGemfileError, "Undefined local variable or method `#{name}' for Gemfile" unless Bundler::Dsl.method_defined? name
+      end
+
+      def source(source, *args, &blk)
+        options = args.last.is_a?(Hash) ? args.pop.dup : {}
+        options = normalize_hash(options)
+        return super unless options.key?("type")
+
+        plugin_name = "bundler-source-#{options["type"]}"
+
+        return if @dependencies.any? {|d| d.name == plugin_name }
+
+        plugin(plugin_name)
+        @inferred_plugins << plugin_name
+      end
+    end
+  end
+end