don't install plugins in excluded groups

bundler/lib/bundler/plugin.rb

@@ -117,7 +117,7 @@ def gemfile_install(gemfile = nil, unlock: false, &inline)
           Installer.new.install_definition(definition)
         end
 
-        plugins = definition.dependencies.map(&:name)
+        plugins = definition.requested_dependencies.select(&:should_include?).map(&:name)
         installed_specs = plugins.to_h {|p| [p, definition.specs[p].first] }
 
         save_plugins plugins, installed_specs, builder.inferred_plugins

bundler/spec/plugins/install_spec.rb

@@ -251,6 +251,44 @@ def exec(command, args)
       expect(out).to include("Bundle complete!")
     end
 
+    it "installs plugins in included groups" do
+      gemfile <<-G
+        source '#{file_uri_for(gem_repo2)}'
+        group :development do
+          plugin 'foo'
+        end
+        gem 'rack', "1.0.0"
+      G
+
+      bundle "install"
+
+      expect(out).to include("Installed plugin foo")
+
+      expect(out).to include("Bundle complete!")
+
+      expect(the_bundle).to include_gems("rack 1.0.0")
+      plugin_should_be_installed("foo")
+    end
+
+    it "does not install plugins in excluded groups" do
+      gemfile <<-G
+        source '#{file_uri_for(gem_repo2)}'
+        group :development do
+          plugin 'foo'
+        end
+        gem 'rack', "1.0.0"
+      G
+
+      bundle "install --without development"
+
+      expect(out).not_to include("Installed plugin foo")
+
+      expect(out).to include("Bundle complete!")
+
+      expect(the_bundle).to include_gems("rack 1.0.0")
+      plugin_should_not_be_installed("foo")
+    end
+
     it "upgrade plugins version listed in gemfile" do
       update_repo2 do
         build_plugin "foo", "1.4.0"