Remove the inconsistent special case for foreign_object.respond_to?(:class)

Author: eregon

CHANGELOG.md

@@ -48,6 +48,7 @@ Changes:
 * `foreign_object.class` on foreign objects is no longer special and uses `Kernel#class` (it used to return the `java.lang.Class` object for a Java type or `getMetaObject()`, but that is too incompatible with Ruby code).
 * `Java.import name` imports a Java class in the enclosing module instead of always as a top-level constant.
 * `foreign_object.keys` no longer returns members, use `foreign_object.instance_variables` or `foreign_object.methods` instead.
+* `foreign_object.respond_to?(:class)` is now always true (before it was only for Java classes), since the method is always defined.
 
 # 21.2.0
 

doc/contributor/interop.md

@@ -113,8 +113,6 @@ runtime object instance.
 
 `foreign_object.kind_of?` works like `foreign_object.is_a?`.
 
-`object.respond_to?(:class)` calls `Truffle::Interop.java_class?(object)`.
-
 `object.respond_to?(name)` for other names returns `false`.
 
 `object.__send__(name, *args)` works in the same way as literal method call on

doc/user/polyglot.md

@@ -110,8 +110,6 @@ If you want to pass a Ruby object to another language for fields to be read and
 
 `object.respond_to?(:new)` will tell you if a foreign object can be used to create a new object (if it's a class).
 
-`object.respond_to?(:class)` will tell you if an object is a Java class.
-
 `Polyglot.as_enumerable(object)` will create a Ruby `Enumerable` from the foreign object, using its size or length, and reading from it.
 
 Where boolean value is expected (e.g., in `if` conditions) the foreign value is converted to boolean if possible or considered to be true.

spec/truffle/interop/respond_to_spec.rb

@@ -62,18 +62,4 @@
       Truffle::Interop.java_array(1, 2, 3).should.respond_to?(:is_a?)
     end
   end
-
-  describe "for :class" do
-    it "and a Java class returns true" do
-      Truffle::Debug.java_class.should.respond_to?(:class)
-    end
-
-    it "and a Java object returns false" do
-      Truffle::Debug.java_object.should_not.respond_to?(:class)
-    end
-
-    it "and a Java array returns false" do
-      Truffle::Interop.java_array(1, 2, 3).should_not.respond_to?(:class)
-    end
-  end
 end

src/main/ruby/truffleruby/core/truffle/polyglot.rb

@@ -342,15 +342,6 @@ def inspect
   end
 
   class ForeignObject < Object
-    def respond_to?(name, include_all = false)
-      case symbol = name.to_sym
-      when :class
-        Truffle::Interop.java_class?(self)
-      else
-        super(symbol, include_all)
-      end
-    end
-
     def inspect
       recursive_string_for(self) if Truffle::ThreadOperations.detect_recursion self do
         return Truffle::InteropOperations.foreign_inspect_nonrecursive(self)