Add Integer.try_convert for Ruby 3.1 support

Author: moste00

spec/ruby/core/integer/try_convert_spec.rb

@@ -28,7 +28,28 @@
     it "sends #to_int to the argument and raises TypeError if it's not a kind of Integer" do
       obj = mock("to_int")
       obj.should_receive(:to_int).and_return(Object.new)
-      -> { Integer.try_convert obj }.should raise_error(TypeError)
+      -> {
+        Integer.try_convert obj
+      }.should raise_error(TypeError, "can't convert MockObject to Integer (MockObject#to_int gives Object)")
+    end
+
+    it "responds with a different error message when it raises a TypeError, depending on the type of the non-Integer object :to_int returns" do
+      obj = mock("to_int")
+      obj.should_receive(:to_int).and_return("A String")
+      -> {
+        Integer.try_convert obj
+      }.should raise_error(TypeError, "can't convert MockObject to Integer (MockObject#to_int gives String)")
+    end
+
+    it "responds with a different error message when it raises a TypeError, depending on the type of the argument object :to_int was called on " do
+      class DifferentMockObject
+        def to_int
+          Object.new
+        end
+      end
+      -> {
+        Integer.try_convert DifferentMockObject.new
+      }.should raise_error(TypeError, "can't convert DifferentMockObject to Integer (DifferentMockObject#to_int gives Object)")
     end
 
     it "does not rescue exceptions raised by #to_int" do

spec/tags/core/integer/try_convert_tags.txt

@@ -332,6 +332,19 @@ def zero?
     self == 0
   end
 
+  def self.try_convert(obj)
+    unless obj.respond_to?(:to_int)
+      return nil
+    end
+
+    result = obj.to_int
+    if Primitive.nil?(result) or Primitive.object_kind_of?(result, Integer)
+      return result
+    end
+
+    Truffle::Type.conversion_mismatch_into(obj, Integer, :to_int, result)
+  end
+
   def self.sqrt(n)
     n = Primitive.rb_to_int(n)
     raise Math::DomainError if n.negative?

src/main/ruby/truffleruby/core/integer.rb

@@ -187,6 +187,12 @@ def self.conversion_mismatch(obj, cls, meth, res)
       raise TypeError, "can't convert #{oc} to #{cls} (#{oc}##{meth} gives #{Primitive.object_class(res)})"
     end
 
+    # Same as conversion mismatch, with a tiny difference in error message ("into" instead of "to")
+    def self.conversion_mismatch_into(obj, cls, meth, res)
+      oc = Primitive.object_class(obj)
+      raise TypeError, "can't convert #{oc} into #{cls} (#{oc}##{meth} gives #{Primitive.object_class(res)})"
+    end
+
     def self.fits_into_int?(val)
       Integer === val && Primitive.integer_fits_into_int(val)
     end