From a06f1ed3b9bf1cde6e23b0d7315bf33cbdcda59d Mon Sep 17 00:00:00 2001
From: Hubert Plociniczak <hubert.plociniczak@gmail.com>
Date: Mon, 9 May 2022 15:32:16 +0200
Subject: [PATCH] Fix infinite loop by doing deep copy (#3441)

Patch provided by Jaroslav, appears to fix local issues with inifite loop
introduced in https://github.com/enso-org/enso/pull/3429.

### Important Notes

This renders https://github.com/enso-org/enso/pull/3439 obsolete. Related to https://www.pivotaltracker.com/n/projects/2539304/stories/182024911
---
 .../interpreter/node/ClosureRootNode.java     |  4 +++
 .../enso/interpreter/node/MethodRootNode.java | 29 +++++++++++++++++--
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/engine/runtime/src/main/java/org/enso/interpreter/node/ClosureRootNode.java b/engine/runtime/src/main/java/org/enso/interpreter/node/ClosureRootNode.java
index 0646aab105a8..04b2e55d033e 100644
--- a/engine/runtime/src/main/java/org/enso/interpreter/node/ClosureRootNode.java
+++ b/engine/runtime/src/main/java/org/enso/interpreter/node/ClosureRootNode.java
@@ -73,4 +73,8 @@ public Object execute(VirtualFrame frame) {
     state = FrameUtil.getObjectSafe(frame, this.getStateFrameSlot());
     return new Stateful(state, result);
   }
+
+  final ExpressionNode getBody() {
+    return body;
+  }
 }
diff --git a/engine/runtime/src/main/java/org/enso/interpreter/node/MethodRootNode.java b/engine/runtime/src/main/java/org/enso/interpreter/node/MethodRootNode.java
index 0a424ae1ca0f..89dca9c37957 100644
--- a/engine/runtime/src/main/java/org/enso/interpreter/node/MethodRootNode.java
+++ b/engine/runtime/src/main/java/org/enso/interpreter/node/MethodRootNode.java
@@ -1,7 +1,9 @@
 package org.enso.interpreter.node;
 
+import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.dsl.ReportPolymorphism;
 import com.oracle.truffle.api.frame.VirtualFrame;
+import com.oracle.truffle.api.nodes.Node;
 import com.oracle.truffle.api.nodes.NodeInfo;
 import com.oracle.truffle.api.source.SourceSection;
 import java.util.function.Supplier;
@@ -108,6 +110,18 @@ public String getMethodName() {
     return methodName;
   }
 
+  @Override
+  public Node deepCopy() {
+    LazyBodyNode.replaceLazyNode(getBody());
+    return super.deepCopy();
+  }
+
+  @Override
+  public Node copy() {
+    LazyBodyNode.replaceLazyNode(getBody());
+    return super.copy();
+  }
+
   private static class LazyBodyNode extends ExpressionNode {
     private final Supplier<ExpressionNode> provider;
 
@@ -115,11 +129,22 @@ private static class LazyBodyNode extends ExpressionNode {
       this.provider = body;
     }
 
+    static void replaceLazyNode(Node n) {
+      if (n instanceof LazyBodyNode lazy) {
+        lazy.replaceItself();
+      }
+    }
+
     @Override
     public Object executeGeneric(VirtualFrame frame) {
-      ExpressionNode newNode = replace(provider.get());
-      notifyInserted(newNode);
+      ExpressionNode newNode = replaceItself();
       return newNode.executeGeneric(frame);
     }
+
+    final ExpressionNode replaceItself() {
+        ExpressionNode newNode = replace(provider.get());
+        notifyInserted(newNode);
+        return newNode;
+    }
   }
 }