Don't display singleton class in Method#inspect unless method defined there

Previously, if an object has a singleton class, and you call
Object#method on the object, the resulting string would include
the object's singleton class, even though the method was not
defined in the singleton class.

Change this so the we only show the singleton class if the method
is defined in the singleton class.

Fixes [Bug #15608]

(cherry picked from commit e02bd0e713ef920e6d12c27f16548f48ec5c2cf0)

1 files changed, 18 insertions, 0 deletions

diff --git a/spec/ruby/core/method/shared/to_s.rb b/spec/ruby/core/method/shared/to_s.rb
index 373398a785..7666322936 100644
--- a/spec/ruby/core/method/shared/to_s.rb
+++ b/spec/ruby/core/method/shared/to_s.rb
@@ -31,4 +31,22 @@ describe :method_to_s, shared: true do
   it "returns a String containing the Module the method is referenced from" do
     @string.should =~ /MethodSpecs::MySub/
   end
+
+  ruby_version_is '2.8' do
+    it "returns a String containing the Module containing the method if object has a singleton class but method is not defined in the singleton class" do
+      obj = MethodSpecs::MySub.new
+      obj.singleton_class
+      @m = obj.method(:bar)
+      @string = @m.send(@method).sub(/0x\w+/, '0xXXXXXX')
+      @string.should =~ /\A#<Method: MethodSpecs::MySub\(MethodSpecs::MyMod\)#bar\(\) /
+    end
+  end
+
+  it "returns a String containing the singleton class if method is defined in the singleton class" do
+    obj = MethodSpecs::MySub.new
+    def obj.bar; end
+    @m = obj.method(:bar)
+    @string = @m.send(@method).sub(/0x\w+/, '0xXXXXXX')
+    @string.should =~ /\A#<Method: #<MethodSpecs::MySub:0xXXXXXX>\.bar/
+  end
 end