Fix WeakMap and WeakSet comparison handling

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

@@ -173,6 +173,11 @@ function innerDeepEqual(val1, val2, strict, memos) {
     return false;
   }
 
+  // Handle WeakMap and WeakSet
+  if (val1Tag === '[object WeakMap]' || val1Tag === '[object WeakSet]') {
+    return val1 === val2;
+  }
+
   if (ArrayIsArray(val1)) {
     // Check for sparse arrays and general fast path
     if (!ArrayIsArray(val2) || val1.length !== val2.length) {

test/parallel/test-assert-deep.js

@@ -1300,3 +1300,44 @@ 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
+  );
+}