fix(ext/web): ReadableStream.from() allows Iterable instead of `I…

…terableIterator` (denoland#23903) `createAsyncFromSyncIterator(x)` which is used in `ReadableStream.from()` expects `x` as `Iterable` but, previous implements specify `Iterator` or `IterableIterator`. If it was `IterableIterator`, it would work, but if it was `Iterator`, an exception will occur. Tests have been merged into WPT. web-platform-tests/wpt#46365 --------- Co-authored-by: Asher Gomez <[email protected]>
dsherret · May 27, 2024 · 35e5159 · 35e5159
1 parent e44c538
commit 35e5159
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Showing 2 changed files with 32 additions and 31 deletions.
diff --git a/ext/web/06_streams.js b/ext/web/06_streams.js
@@ -5088,28 +5088,32 @@ function initializeCountSizeFunction(globalObject) {
  WeakMapPrototypeSet(countSizeFunctionWeakMap, globalObject, size);
 }
 
-async function* createAsyncFromSyncIterator(syncIterator) {
- // deno-lint-ignore prefer-primordials
- yield* syncIterator;
-}
-
 // Ref: https://tc39.es/ecma262/#sec-getiterator
-function getIterator(obj, async = false) {
- if (async) {
- if (obj[SymbolAsyncIterator] == null) {
- if (obj[SymbolIterator] == null) {
- throw new TypeError("No iterator found");
- }
- return createAsyncFromSyncIterator(obj[SymbolIterator]());
- } else {
- return obj[SymbolAsyncIterator]();
+function getAsyncOrSyncIterator(obj) {
+ let iterator;
+ if (obj[SymbolAsyncIterator] != null) {
+ iterator = obj[SymbolAsyncIterator]();
+ if (!isObject(iterator)) {
+ throw new TypeError(
+ "[Symbol.asyncIterator] returned a non-object value",
+ );
  }
- } else {
- if (obj[SymbolIterator] == null) {
- throw new TypeError("No iterator found");
+ } else if (obj[SymbolIterator] != null) {
+ iterator = obj[SymbolIterator]();
+ if (!isObject(iterator)) {
+ throw new TypeError("[Symbol.iterator] returned a non-object value");
  }
- return obj[SymbolIterator]();
+ } else {
+ throw new TypeError("No iterator found");
+ }
+ if (typeof iterator.next !== "function") {
+ throw new TypeError("iterator.next is not a function");
  }
+ return iterator;
+}
+
+function isObject(x) {
+ return (typeof x === "object" && x != null) || typeof x === "function";
 }
 
 const _resourceBacking = Symbol("[[resourceBacking]]");
@@ -5204,26 +5208,29 @@ class ReadableStream {
  );
  asyncIterable = webidl.converters.any(asyncIterable);
 
- const iterator = getIterator(asyncIterable, true);
+ const iterator = getAsyncOrSyncIterator(asyncIterable);
 
  const stream = createReadableStream(noop, async () => {
  // deno-lint-ignore prefer-primordials
  const res = await iterator.next();
- if (typeof res !== "object") {
+ if (!isObject(res)) {
  throw new TypeError("iterator.next value is not an object");
  }
  if (res.done) {
  readableStreamDefaultControllerClose(stream[_controller]);
  } else {
- readableStreamDefaultControllerEnqueue(stream[_controller], res.value);
+ readableStreamDefaultControllerEnqueue(
+ stream[_controller],
+ await res.value,
+ );
  }
  }, async (reason) => {
- if (typeof iterator.return === "undefined") {
+ if (iterator.return == null) {
  return undefined;
  } else {
  // deno-lint-ignore prefer-primordials
  const res = await iterator.return(reason);
- if (typeof res !== "object") {
+ if (!isObject(res)) {
  throw new TypeError("iterator.return value is not an object");
  } else {
  return undefined;

diff --git a/tests/wpt/runner/expectation.json b/tests/wpt/runner/expectation.json
@@ -3170,14 +3170,8 @@
  "owning-type-message-port.any.worker.html": false,
  "owning-type.any.html": false,
  "owning-type.any.worker.html": false,
- "from.any.html": [
- "ReadableStream.from accepts a sync iterable of values",
- "ReadableStream.from accepts a sync iterable of promises"
- ],
- "from.any.worker.html": [
- "ReadableStream.from accepts a sync iterable of values",
- "ReadableStream.from accepts a sync iterable of promises"
- ]
+ "from.any.html": true,
+ "from.any.worker.html": true
  },
  "transform-streams": {
  "backpressure.any.html": true,