toDisplayString() should show the #inspect result for ImmutableRubyString

Author: eregon

src/main/java/org/truffleruby/language/ImmutableRubyObject.java

@@ -9,6 +9,7 @@
  */
 package org.truffleruby.language;
 
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import org.truffleruby.RubyContext;
 import org.truffleruby.RubyLanguage;
 import org.truffleruby.cext.ValueWrapper;
@@ -89,8 +90,11 @@ public Class<RubyLanguage> getLanguage() {
         return RubyLanguage.class;
     }
 
+    @TruffleBoundary
     @ExportMessage
-    public abstract String toDisplayString(boolean allowSideEffects);
+    public String toDisplayString(boolean allowSideEffects) {
+        throw new AbstractMethodError();
+    }
 
     // region Members
     @ExportMessage

src/main/java/org/truffleruby/language/ImmutableRubyString.java

@@ -17,11 +17,13 @@
 import com.oracle.truffle.api.library.ExportMessage;
 import org.truffleruby.RubyContext;
 import org.truffleruby.RubyLanguage;
+import org.truffleruby.core.kernel.KernelNodes;
 import org.truffleruby.core.klass.RubyClass;
 import org.truffleruby.core.rope.LeafRope;
 import org.truffleruby.core.rope.Rope;
 import org.truffleruby.core.rope.RopeOperations;
 import org.truffleruby.interop.ToJavaStringNode;
+import org.truffleruby.language.dispatch.DispatchNode;
 import org.truffleruby.language.library.RubyStringLibrary;
 
 
@@ -59,10 +61,15 @@ public String getJavaString() {
     // endregion
 
     // region InteropLibrary messages
-    @Override
     @ExportMessage
-    public String toDisplayString(boolean allowSideEffects) {
-        return RopeOperations.decodeRope(rope);
+    public Object toDisplayString(boolean allowSideEffects,
+            @Cached DispatchNode dispatchNode,
+            @Cached KernelNodes.ToSNode kernelToSNode) {
+        if (allowSideEffects) {
+            return dispatchNode.call(this, "inspect");
+        } else {
+            return kernelToSNode.executeToS(this);
+        }
     }
 
     @ExportMessage