Fix WeakMap and WeakSet comparison handling

Author: synapse

doc/api/assert.md

@@ -634,7 +634,8 @@ are also recursively evaluated by the following rules.
 * Implementation does not test the [`[[Prototype]]`][prototype-spec] of
   objects.
 * [`Symbol`][] properties are not compared.
-* [`WeakMap`][] and [`WeakSet`][] comparison does not rely on their values.
+* [`WeakMap`][] and [`WeakSet`][] comparison does not rely on their values
+  but only on their instances.
 * [`RegExp`][] lastIndex, flags, and source are always compared, even if these
   are not enumerable properties.
 

lib/internal/util/comparisons.js

@@ -46,6 +46,8 @@ const {
   isFloat64Array,
   isKeyObject,
   isCryptoKey,
+  isWeakMap,
+  isWeakSet,
 } = types;
 const {
   constants: {
@@ -283,7 +285,10 @@ function innerDeepEqual(val1, val2, strict, memos) {
     ) {
       return false;
     }
+  } else if (isWeakMap(val1) || isWeakSet(val1)) {
+    return val1 === val2;
   }
+
   return keyCheck(val1, val2, strict, memos, kNoIterator);
 }
 

test/parallel/test-assert-deep.js

@@ -1300,3 +1300,43 @@ if (common.hasCrypto) {
     }
   })().then(common.mustCall());
 }
+
+// Comparing two identical WeakMap instances
+{
+  const weakMap1 = new WeakMap();
+  const weakMap2 = weakMap1;
+  assert.deepStrictEqual(weakMap1, weakMap2);
+}
+
+// Comparing two different WeakMap instances
+{
+  const weakMap1 = new WeakMap();
+  const objA = {};
+  weakMap1.set(objA, 'ok');
+
+  const weakMap2 = new WeakMap();
+  const objB = {};
+  weakMap2.set(objB, 'ok');
+
+  assert.throws(
+    () => assert.deepStrictEqual(weakMap1, weakMap2),
+    Error
+  );
+}
+
+// Comparing two identical WeakSet instances
+{
+  const weakSet1 = new WeakSet();
+  const weakSet2 = weakSet1;
+  assert.deepStrictEqual(weakSet1, weakSet2);
+}
+
+// Comparing two different WeakSet instances
+{
+  const weakSet1 = new WeakSet();
+  const weakSet2 = new WeakSet();
+  assert.throws(
+    () => assert.deepStrictEqual(weakSet1, weakSet2),
+    Error
+  );
+}