Warn when loading a plugin with arguments or a block if the plugin do…

…es not accept arguments or block

Previously, if the plugin didn't have a load_dependencies or
configure method, any arguments or block passed to it would be
ignored.  That can cause problems if the plugin has a configure
or load_dependencies method added later that supports a block or
optional arguments.

CHANGELOG

@@ -1,3 +1,7 @@
+= master
+
+* Warn when loading a plugin with arguments or a block if the plugin does not accept arguments or block (jeremyevans)
+
 = 3.34.0 (2020-07-14)
 
 * Remove unnecessary conditionals (jeremyevans)

lib/roda.rb

@@ -272,6 +272,12 @@ def plugin(plugin, *args, &block)
           raise RodaError, "Cannot add a plugin to a frozen Roda class" if frozen?
           plugin = RodaPlugins.load_plugin(plugin) if plugin.is_a?(Symbol)
           raise RodaError, "Invalid plugin type: #{plugin.class.inspect}" unless plugin.is_a?(Module)
+
+          if !plugin.respond_to?(:load_dependencies) && !plugin.respond_to?(:configure) && (!args.empty? || block)
+            # RODA4: switch from warning to error
+            RodaPlugins.warn("Plugin #{plugin} does not accept arguments or a block, but arguments or a block was passed when loading this. This will raise an error in Roda 4.")
+          end
+
           plugin.load_dependencies(self, *args, &block) if plugin.respond_to?(:load_dependencies)
           include(plugin::InstanceMethods) if defined?(plugin::InstanceMethods)
           extend(plugin::ClassMethods) if defined?(plugin::ClassMethods)

spec/plugin_spec.rb

@@ -71,6 +71,13 @@ def self.configure(mod, prefix)
     body.must_equal '1'
   end
 
+  it "should warn if attempting to load a plugin with arguments or a block" do
+    Roda::RodaPlugins.register_plugin(:foo, Module.new)
+    proc{app.plugin :foo, 1}.must_output(nil, /does not accept arguments or a block/)
+    @app = nil
+    proc{app.plugin(:foo){}}.must_output(nil, /does not accept arguments or a block/)
+  end
+
   it "should raise error if attempting to load an invalid plugin" do
     proc{app(:banana)}.must_raise LoadError