Async/await catch prediction for "the synchronous case"

test/mjsunit/harmony/async-debug-caught-exception-cases.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-async-await --expose-debug-as debug
+
+Debug = debug.Debug
+
+let events = 0;
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Exception) return;
+  events++;
+}
+
+async function thrower() {
+  throw "a";  // Exception a
+}
+
+var reject = () => Promise.reject("b");  // Exception b
+
+async function awaitReturn() { await 1; return; }
+
+async function scalar() { return 1; }
+
+function nothing() { return 1; }
+
+function rejectConstructor() {
+  return new Promise((resolve, reject) => reject("c"));  // Exception c
+}
+
+async function argThrower(x = (() => { throw "d"; })()) { }  // Exception d
+
+function suppressThrow() {
+  return thrower();
+}
+
+async function caught(producer) {
+  try {
+    await producer();
+  } catch (e) {
+  }
+}
+
+async function uncaught(producer) {
+  await producer();
+}
+
+async function indirectUncaught(producer) {
+  await uncaught(producer);
+}
+
+async function indirectCaught(producer) {
+  try {
+    await uncaught(producer);
+  } catch (e) {
+  }
+}
+
+function dotCatch(producer) {
+  Promise.resolve(producer()).catch(() => {});
+}
+
+function indirectReturnDotCatch(producer) {
+  (async() => producer())().catch(() => {});
+}
+
+function indirectAwaitDotCatch(producer) {
+  (async() => await producer())().catch(() => {});
+}
+
+function nestedDotCatch(producer) {
+  Promise.resolve(producer()).then().catch(() => {});
+}
+
+async function indirectAwaitCatch(producer) {
+  try {
+    await (() => producer())();
+  } catch (e) {
+  }
+}
+
+let catches = [caught, indirectCaught, indirectAwaitCatch];
+let noncatches = [uncaught, indirectUncaught];
+let lateCatches = [dotCatch,
+                   indirectReturnDotCatch,
+                   indirectAwaitDotCatch,
+                   nestedDotCatch];
+
+let throws = [thrower, reject, argThrower, suppressThrow];
+let nonthrows = [awaitReturn, scalar, nothing];
+let uncatchable = [rejectConstructor];
+
+let cases = [];
+
+for (let producer of throws) {
+  for (let consumer of catches) {
+    cases.push({ producer, consumer, expectedEvents: 1, caught: true });
+    cases.push({ producer, consumer, expectedEvents: 0, caught: false });
+  }
+}
+
+for (let producer of throws) {
+  for (let consumer of noncatches) {
+    cases.push({ producer, consumer, expectedEvents: 1, caught: true });
+    cases.push({ producer, consumer, expectedEvents: 1, caught: false });
+  }
+}
+
+for (let producer of nonthrows) {
+  for (let consumer of catches.concat(noncatches, lateCatches)) {
+    cases.push({ producer, consumer, expectedEvents: 0, caught: true });
+    cases.push({ producer, consumer, expectedEvents: 0, caught: false });
+  }
+}
+
+for (let producer of uncatchable) {
+  for (let consumer of catches.concat(noncatches, lateCatches)) {
+    cases.push({ producer, consumer, expectedEvents: 1, caught: true });
+    cases.push({ producer, consumer, expectedEvents: 1, caught: false });
+  }
+}
+
+for (let producer of throws) {
+  for (let consumer of lateCatches) {
+    cases.push({ producer, consumer, expectedEvents: 1, caught: true });
+    cases.push({ producer, consumer, expectedEvents: 1, caught: false });
+  }
+}
+
+for (let {producer, consumer, expectedEvents, caught} of cases) {
+  Debug.setListener(listener);
+  if (caught) {
+    Debug.setBreakOnException();
+  } else {
+    Debug.setBreakOnUncaughtException();
+  }
+
+  events = 0;
+  consumer(producer);
+  %RunMicrotasks();
+
+  Debug.setListener(null);
+  if (caught) {
+    Debug.clearBreakOnException();
+  } else {
+    Debug.clearBreakOnUncaughtException();
+  }
+  if (expectedEvents != events) {
+    print(`producer ${producer} consumer ${consumer} expectedEvents ` +
+          `${expectedEvents} caught ${caught} events ${events}`);
+    quit(1);
+  }
+}