Changeset 209113 in webkit

Timestamp:

Nov 29, 2016, 7:42:55 PM (9 years ago)

Author:

caitp@igalia.com

Message:

[JSC] always wrap AwaitExpression operand in a new Promise
​https://bugs.webkit.org/show_bug.cgi?id=165181

Reviewed by Yusuke Suzuki.

JSTests:

• stress/async-await-basic.js:

(async.awaitedPromisesAreWrapped):

Source/JavaScriptCore:

Ensure operand of AwaitExpression is wrapped in a new Promise by
explicitly creating a new Promise Capability and invoking its
resolve callback. This avoids the specified short-circuit for
Promise.resolve().

• builtins/AsyncFunctionPrototype.js:

(globalPrivate.asyncFunctionResume):

Location:

trunk

Files:

• JSTests/ChangeLog (modified) (1 diff)
• JSTests/stress/async-await-basic.js (modified) (1 diff)
• Source/JavaScriptCore/ChangeLog (modified) (1 diff)
• Source/JavaScriptCore/builtins/AsyncFunctionPrototype.js (modified) (1 diff)

trunk/JSTests/ChangeLog

@@ +1 @@
+2016-11-29  Caitlin Potter  <caitp@igalia.com>
+
+        [JSC] always wrap AwaitExpression operand in a new Promise
+        https://bugs.webkit.org/show_bug.cgi?id=165181
+
+        Reviewed by Yusuke Suzuki.
+
+        * stress/async-await-basic.js:
+        (async.awaitedPromisesAreWrapped):
+
 2016-11-29  Keith Miller  <keith_miller@apple.com>
 

trunk/JSTests/stress/async-await-basic.js

@@ -295 +295 @@
 shouldThrowSyntaxError("class C { async ['foo'] , bar };", "Unexpected token ','. Expected an opening '(' before a async method's parameter list.");
 shouldThrowSyntaxError("class C { async ['foo'] }", "Unexpected token '}'. Expected an opening '(' before a async method's parameter list.");
+
+// Ensure awaited builtin Promise objects are themselves wrapped in a new Promise,
+// per https://tc39.github.io/ecma262/#sec-async-functions-abstract-operations-async-function-await
+log = [];
+async function awaitedPromisesAreWrapped() {
+    log.push("before");
+    await Promise.resolve();
+    log.push("after");
+}
+awaitedPromisesAreWrapped();
+Promise.resolve().then(() => log.push("Promise.resolve()"));
+drainMicrotasks();
+shouldBe("before|Promise.resolve()|after", log.join("|"));

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2016-11-29  Caitlin Potter  <caitp@igalia.com>
+
+        [JSC] always wrap AwaitExpression operand in a new Promise
+        https://bugs.webkit.org/show_bug.cgi?id=165181
+
+        Reviewed by Yusuke Suzuki.
+
+        Ensure operand of AwaitExpression is wrapped in a new Promise by
+        explicitly creating a new Promise Capability and invoking its
+        resolve callback. This avoids the specified short-circuit for
+        Promise.resolve().
+
+        * builtins/AsyncFunctionPrototype.js:
+        (globalPrivate.asyncFunctionResume):
+
 2016-11-29  Saam Barati  <sbarati@apple.com>
 

trunk/Source/JavaScriptCore/builtins/AsyncFunctionPrototype.js

@@ -48 +48 @@
     }
 
-    @Promise.@resolve(value).@then(
+    let wrappedValue = @newPromiseCapability(@Promise);
+    wrappedValue.@resolve.@call(@undefined, value);
+
+    wrappedValue.@promise.@then(
         function(value) { @asyncFunctionResume(generator, promiseCapability, value, @GeneratorResumeModeNormal); },
         function(error) { @asyncFunctionResume(generator, promiseCapability, error, @GeneratorResumeModeThrow); });