worker script evaluation resulting in abrupt completion shouldn't be …

…a start failure Differential Revision: https://phabricator.services.mozilla.com/D62371 bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1603484 gecko-commit: fb7235b2a1b3c94f278ae2175ad826119ffca08f gecko-integration-branch: autoland gecko-reviewers: dom-workers-and-storage-reviewers, asuth
web-platform-tests · Feb 13, 2020 · 12dc834 · 12dc834
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diff --git a/workers/abrupt-completion.html b/workers/abrupt-completion.html
@@ -0,0 +1,55 @@
+<!doctype html>
+<meta charset=utf-8>
+<title></title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script>
+
+// Tests that a {Dedicated,Shared}Worker keeps running even if its script
+// evaluation results in an abrupt completion. This corresponds to the "run a
+// worker" algorithm disregarding the return value of "run the {classic,module}
+// script" in its step 24:
+//
+// "If script is a classic script, then run the classic script script.
+// Otherwise, it is a module script; run the module script script."
+
+async function testWorker(worker) {
+  await new Promise(resolve => {
+    worker.onerror = e => {
+      assert_not_equals(e.message.search("uncaught-exception"), -1,
+                        "Correct uncaught exception thrown by worker");
+
+      // Suppress the exception.
+      e.preventDefault();
+
+      resolve();
+    }
+  });
+
+  return new Promise(resolve => {
+    const channel = new MessageChannel();
+
+    channel.port1.onmessage = e => {
+      assert_equals(e.data, "handler-before-throw", "Correct message handler.");
+      resolve();
+    };
+
+    if (worker instanceof SharedWorker) {
+      worker.port.postMessage("", [channel.port2]);
+    } else {
+      worker.postMessage("", [channel.port2]);
+    }
+  });
+}
+
+promise_test(async t => {
+  const worker = new Worker("support/abrupt-completion.js");
+  return testWorker(worker);
+}, "DedicatedWorker should correctly handle abrupt completion");
+
+promise_test(async t => {
+  const worker = new SharedWorker("support/abrupt-completion.js");
+  return testWorker(worker);
+}, "SharedWorker should correctly handle abrupt completion");
+
+</script>
diff --git a/workers/support/abrupt-completion.js b/workers/support/abrupt-completion.js
@@ -0,0 +1,21 @@
+const isSharedWorker =
+  "SharedWorkerGlobalScope" in self && self instanceof SharedWorkerGlobalScope;
+
+function setMessageHandler(response) {
+  onmessage = e => {
+    e.ports[0].postMessage(response);
+  };
+
+  if (isSharedWorker) {
+    onconnect = e => {
+      e.ports[0].onmessage = onmessage;
+    };
+  }
+}
+
+setMessageHandler("handler-before-throw");
+
+throw new Error("uncaught-exception");
+
+// This should never be called because of the uncaught exception above.
+setMessageHandler("handler-after-throw");