stream: validate ReadableStream.from iterator objects

Signed-off-by: Daeyeon Jeong <[email protected]>
PR-URL: #62911
Reviewed-By: Filip Skokan <[email protected]>
Reviewed-By: Matthew Aitken <[email protected]>
Reviewed-By: Mattias Buelens <[email protected]>

Author: daeyeon

lib/internal/webstreams/readablestream.js

@@ -1365,6 +1365,9 @@ function readableStreamFromIterable(iterable) {
     throw new ERR_ARG_NOT_ITERABLE(iterable);
   }
   const iterator = FunctionPrototypeCall(iteratorGetter, iterable);
+  if (iterator === null || (typeof iterator !== 'object' && typeof iterator !== 'function')) {
+    throw new ERR_INVALID_STATE.TypeError('The iterator method must return an object');
+  }
   const startAlgorithm = nonOpStart;
 
   async function pullAlgorithm() {

test/parallel/test-webstream-readable-from.js

@@ -7,3 +7,22 @@ assert.throws(
   () => ReadableStream.from({}),
   { code: 'ERR_ARG_NOT_ITERABLE', name: 'TypeError' },
 );
+
+const invalidIterators = [
+  { [Symbol.iterator]: () => 42 },
+  { [Symbol.asyncIterator]: () => 42 },
+];
+
+for (const iterable of invalidIterators) {
+  assert.throws(
+    () => ReadableStream.from(iterable),
+    { code: 'ERR_INVALID_STATE', name: 'TypeError' },
+  );
+}
+
+function functionIterator() {}
+
+// doesNotThrow
+ReadableStream.from({
+  [Symbol.iterator]: () => functionIterator,
+});

test/wpt/status/streams.json

@@ -8,15 +8,6 @@
   "readable-streams/cross-realm-crash.window.js": {
     "skip": "Browser-specific test"
   },
-  "readable-streams/from.any.js": {
-    "fail": {
-      "note": "does not synchronously validate that the value returned by @@iterator/@@asyncIterator is an object",
-      "expected": [
-        "ReadableStream.from throws on invalid iterables; specifically an object with an @@iterator method returning a non-object",
-        "ReadableStream.from throws on invalid iterables; specifically an object with an @@asyncIterator method returning a non-object"
-      ]
-    }
-  },
   "readable-streams/owning-type-message-port.any.js": {
     "fail": {
       "note": "Readable streams with type owning are not yet supported",