Use target obj as self for instance_eval. Fixes #2301.

Author: headius

core/src/main/java/org/jruby/RubyBasicObject.java

@@ -1574,7 +1574,7 @@ public IRubyObject instance_exec19(ThreadContext context, IRubyObject[] args, Bl
      * with this implementation.
      */
     protected IRubyObject yieldUnder(final ThreadContext context, RubyModule under, IRubyObject[] args, Block block) {
-        context.preExecuteUnder(under, block);
+        context.preExecuteUnder(this, under, block);
 
         IRubyObject savedBindingSelf = block.getBinding().getSelf();
         IRubyObject savedFrameSelf = block.getBinding().getFrame().getSelf();
@@ -1616,7 +1616,7 @@ private Block setupBlock(Block block) {
      * with this implementation.
      */
     protected IRubyObject yieldUnder(final ThreadContext context, RubyModule under, Block block) {
-        context.preExecuteUnder(under, block);
+        context.preExecuteUnder(this, under, block);
 
         IRubyObject savedBindingSelf = block.getBinding().getSelf();
         IRubyObject savedFrameSelf = block.getBinding().getFrame().getSelf();
@@ -1759,7 +1759,7 @@ protected RubyModule getInstanceEvalClass() {
     public IRubyObject evalUnder(final ThreadContext context, RubyModule under, RubyString src, String file, int line) {
         Visibility savedVisibility = context.getCurrentVisibility();
         context.setCurrentVisibility(PUBLIC);
-        context.preExecuteUnder(under, Block.NULL_BLOCK);
+        context.preExecuteUnder(this, under, Block.NULL_BLOCK);
         try {
             return ASTInterpreter.evalSimple(context, this, src,
                     file, line);

core/src/main/java/org/jruby/runtime/ThreadContext.java

@@ -1176,20 +1176,19 @@ public void postNodeEval() {
         popFrame();
         popRubyClass();
     }
-    
-    // XXX: Again, screwy evaling under previous frame's scope
-    public void preExecuteUnder(RubyModule executeUnderClass, Block block) {
+
+    public void preExecuteUnder(IRubyObject self, RubyModule executeUnderClass, Block block) {
         Frame frame = getCurrentFrame();
-        
+
         pushRubyClass(executeUnderClass);
         DynamicScope scope = getCurrentScope();
         StaticScope sScope = runtime.getStaticScopeFactory().newBlockScope(scope.getStaticScope());
         sScope.setModule(executeUnderClass);
         pushScope(DynamicScope.newDynamicScope(sScope, scope));
-        pushCallFrame(frame.getKlazz(), frame.getName(), frame.getSelf(), block);
+        pushCallFrame(frame.getKlazz(), frame.getName(), self, block);
         getCurrentFrame().setVisibility(getPreviousFrame().getVisibility());
     }
-    
+
     public void postExecuteUnder() {
         popFrame();
         popScope();

spec/regression/GH-2301_instance_eval_uses_target_as_self_spec.rb

@@ -0,0 +1,13 @@
+describe "Object#instance_eval" do
+  it "uses the target object as self in the executed code" do
+    o = Object.new
+    o.instance_variable_set :@foo, 1
+    newself, binding = o.instance_eval "[self, binding]"
+    expect(newself).to eq(o)
+    expect(eval('self', binding)).to eq(self)
+
+    newself, binding = o.instance_eval {[self, binding]}
+    expect(newself).to eq(o)
+    expect(eval('self', binding)).to eq(self)
+  end
+end