Bug 1343158 - Restore stack trace for async function after await. r=jimb

js/src/tests/ecma_2017/AsyncFunctions/ErrorStack.js

@@ -0,0 +1,103 @@
+// |reftest| skip-if(!xulRuntime.shell) -- needs drainJobQueue
+
+var BUGNUMBER = 1343158;
+var summary = "Error.stack should provide meaningful stack trace in async function";
+
+print(BUGNUMBER + ": " + summary);
+
+let COOKIE = "C0F5DBB89807";
+
+async function thrower() {
+    let stack = new Error().stack; // line 11
+    assertEq(/^thrower@.+ErrorStack.js:11/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*inner@.+ErrorStack.js:38/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*middle@.+ErrorStack.js:58/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*outer@.+ErrorStack.js:78/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*@.+ErrorStack.js:82/m.test(stack), true, toMessage(stack));
+
+    throw new Error(COOKIE); // line 18
+}
+
+async function inner() {
+    let stack = new Error().stack; // line 22
+    assertEq(/thrower@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/^inner@.+ErrorStack.js:22/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*middle@.+ErrorStack.js:58/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*outer@.+ErrorStack.js:78/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*@.+ErrorStack.js:82/m.test(stack), true, toMessage(stack));
+
+    await Promise.resolve(100);
+
+    stack = new Error().stack; // line 31
+    assertEq(/thrower@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/^inner@.+ErrorStack.js:31/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*middle@.+ErrorStack.js:58/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*outer@.+ErrorStack.js:78/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*@.+ErrorStack.js:82/m.test(stack), true, toMessage(stack));
+
+    await thrower(); // line 38
+}
+
+async function middle() {
+    let stack = new Error().stack; // line 42
+    assertEq(/thrower@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/inner@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/^middle@.+ErrorStack.js:42/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*outer@.+ErrorStack.js:78/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*@.+ErrorStack.js:82/m.test(stack), true, toMessage(stack));
+
+    await Promise.resolve(1000);
+
+    stack = new Error().stack; // line 51
+    assertEq(/thrower@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/inner@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/^middle@.+ErrorStack.js:51/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*outer@.+ErrorStack.js:78/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*@.+ErrorStack.js:82/m.test(stack), true, toMessage(stack));
+
+    await inner(); // line 58
+}
+
+async function outer() {
+    let stack = new Error().stack; // line 62
+    assertEq(/thrower@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/inner@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/middle@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/^outer@.+ErrorStack.js:62/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*@.+ErrorStack.js:82/m.test(stack), true, toMessage(stack));
+
+    await Promise.resolve(10000);
+
+    stack = new Error().stack; // line 71
+    assertEq(/thrower@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/inner@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/middle@.+ErrorStack.js/m.test(stack), false, toMessage(stack));
+    assertEq(/^outer@.+ErrorStack.js:71/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*@.+ErrorStack.js:82/m.test(stack), true, toMessage(stack));
+
+    await middle(); // line 78
+}
+
+try {
+    getPromiseResult(outer()); // line 82
+    assertEq(true, false);
+} catch (e) {
+    // Re-throw the exception to log the assertion failure properly.
+    if (!e.message.includes(COOKIE))
+        throw e;
+
+    let stack = e.stack;
+    assertEq(/^thrower@.+ErrorStack.js:18/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*inner@.+ErrorStack.js:38/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*middle@.+ErrorStack.js:58/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*outer@.+ErrorStack.js:78/m.test(stack), true, toMessage(stack));
+    assertEq(/^async\*@.+ErrorStack.js:82/m.test(stack), true, toMessage(stack));
+}
+
+function toMessage(stack) {
+    // Provide the stack string in the error message for debugging.
+    return `[stack: ${stack.replace(/\n/g, "\\n")}]`;
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);

js/src/tests/shell.js

@@ -737,6 +737,7 @@
       throw error;
     return result;
   }
+  global.getPromiseResult = getPromiseResult;
 
   function assertEventuallyEq(promise, expected) {
     assertEq(getPromiseResult(promise), expected);

js/src/vm/AsyncFunction.cpp

@@ -6,6 +6,8 @@
 
 #include "vm/AsyncFunction.h"
 
+#include "mozilla/Maybe.h"
+
 #include "jscompartment.h"
 
 #include "builtin/Promise.h"
@@ -17,6 +19,8 @@
 using namespace js;
 using namespace js::gc;
 
+using mozilla::Maybe;
+
 /* static */ bool
 GlobalObject::initAsyncFunction(JSContext* cx, Handle<GlobalObject*> global)
 {
@@ -168,6 +172,13 @@ static bool
 AsyncFunctionResume(JSContext* cx, Handle<PromiseObject*> resultPromise, HandleValue generatorVal,
                     ResumeKind kind, HandleValue valueOrReason)
 {
+    RootedObject stack(cx, resultPromise->allocationSite());
+    Maybe<JS::AutoSetAsyncStackForNewCalls> asyncStack;
+    if (stack) {
+        asyncStack.emplace(cx, stack, "async",
+                           JS::AutoSetAsyncStackForNewCalls::AsyncCallKind::EXPLICIT);
+    }
+
     // Execution context switching is handled in generator.
     HandlePropertyName funName = kind == ResumeKind::Normal
                                  ? cx->names().StarGeneratorNext