From edc53e25c1bddee8b4604687a8e7dfc9a51490d9 Mon Sep 17 00:00:00 2001
From: Adam Ruka <adamruka85@gmail.com>
Date: Sat, 20 Apr 2024 16:21:39 -0700
Subject: [PATCH] Allow writes to prototypes directly.

---
 .../part_13/runtime/InteropDynamicObject.java  | 18 ++++++++++++++++++
 .../part_13/runtime/JavaScriptObject.java      |  6 ------
 .../truffle/part_13/InheritanceTest.java       | 18 ++++++++++++++++++
 3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/part-14/src/main/java/com/endoflineblog/truffle/part_13/runtime/InteropDynamicObject.java b/part-14/src/main/java/com/endoflineblog/truffle/part_13/runtime/InteropDynamicObject.java
index 60029076..107d56f7 100644
--- a/part-14/src/main/java/com/endoflineblog/truffle/part_13/runtime/InteropDynamicObject.java
+++ b/part-14/src/main/java/com/endoflineblog/truffle/part_13/runtime/InteropDynamicObject.java
@@ -42,4 +42,22 @@ Object getMembers(@SuppressWarnings("unused") boolean includeInternal,
             @CachedLibrary("this") DynamicObjectLibrary thisObjectLibrary) {
         return new MemberNamesObject(thisObjectLibrary.getKeyArray(this));
     }
+
+    @ExportMessage
+    boolean isMemberModifiable(String member,
+            @CachedLibrary("this") DynamicObjectLibrary thisObjectLibrary) {
+        return this.isMemberReadable(member, thisObjectLibrary);
+    }
+
+    @ExportMessage
+    boolean isMemberInsertable(String member,
+            @CachedLibrary("this") DynamicObjectLibrary thisObjectLibrary) {
+        return !this.isMemberModifiable(member, thisObjectLibrary);
+    }
+
+    @ExportMessage
+    void writeMember(String member, Object value,
+            @CachedLibrary("this") DynamicObjectLibrary thisObjectLibrary) {
+        thisObjectLibrary.put(this, member, value);
+    }
 }
diff --git a/part-14/src/main/java/com/endoflineblog/truffle/part_13/runtime/JavaScriptObject.java b/part-14/src/main/java/com/endoflineblog/truffle/part_13/runtime/JavaScriptObject.java
index 502b9752..1fc2a8c7 100644
--- a/part-14/src/main/java/com/endoflineblog/truffle/part_13/runtime/JavaScriptObject.java
+++ b/part-14/src/main/java/com/endoflineblog/truffle/part_13/runtime/JavaScriptObject.java
@@ -73,10 +73,4 @@ boolean isMemberInsertable(String member,
             @CachedLibrary("this.classPrototypeObject") DynamicObjectLibrary prototypeObjectLibrary) {
         return !this.isMemberModifiable(member, thisObjectLibrary, prototypeObjectLibrary);
     }
-
-    @ExportMessage
-    void writeMember(String member, Object value,
-            @CachedLibrary("this") DynamicObjectLibrary thisObjectLibrary) {
-        thisObjectLibrary.put(this, member, value);
-    }
 }
diff --git a/part-14/src/test/java/com/endoflineblog/truffle/part_13/InheritanceTest.java b/part-14/src/test/java/com/endoflineblog/truffle/part_13/InheritanceTest.java
index 2dc3bf45..14bed56c 100644
--- a/part-14/src/test/java/com/endoflineblog/truffle/part_13/InheritanceTest.java
+++ b/part-14/src/test/java/com/endoflineblog/truffle/part_13/InheritanceTest.java
@@ -179,6 +179,24 @@ void hasOwnProperty_returns_false_for_primitives() {
         assertFalse(result.asBoolean());
     }
 
+    @Test
+    void prototypes_can_be_written_to() {
+        Value result = this.context.eval("ezs", "" +
+                "class Class { " +
+                "    m() { " +
+                "        return 13; " +
+                "    } " +
+                "} " +
+                "function m() { " +
+                "    return 46; " +
+                "} " +
+                "const obj = new Class(); " +
+                "Class.m = m; " +
+                "obj.m(); "
+        );
+        assertEquals(46, result.asInt());
+    }
+
     @Test
     void extending_non_existent_class_is_an_error() {
         try {