Bug 1339999 - Properly handle OOM during exception throwing in all Pr…

…omise code. r=arai

MozReview-Commit-ID: 2uZgTZAKYnK

js/src/builtin/Promise.cpp

@@ -131,6 +131,20 @@ NewPromiseAllDataHolder(JSContext* cx, HandleObject resultPromise, HandleValue v
     return dataHolder;
 }
 
+/**
+ * Wrapper for GetAndClearException that handles cases where no exception is
+ * pending, but an error occurred. This can be the case if an OOM was
+ * encountered while throwing the error.
+ */
+static bool
+MaybeGetAndClearException(JSContext* cx, MutableHandleValue rval)
+{
+    if (!cx->isExceptionPending())
+        return false;
+
+    return GetAndClearException(cx, rval);
+}
+
 static MOZ_MUST_USE bool RunResolutionFunction(JSContext *cx, HandleObject resolutionFun,
                                                HandleValue result, ResolutionMode mode,
                                                HandleObject promiseObj);
@@ -142,13 +156,9 @@ static MOZ_MUST_USE bool RunResolutionFunction(JSContext *cx, HandleObject resol
 static bool
 AbruptRejectPromise(JSContext *cx, CallArgs& args, HandleObject promiseObj, HandleObject reject)
 {
-    // Not much we can do about uncatchable exceptions, so just bail.
-    if (!cx->isExceptionPending())
-        return false;
-
     // Step 1.a.
     RootedValue reason(cx);
-    if (!GetAndClearException(cx, &reason))
+    if (!MaybeGetAndClearException(cx, &reason))
         return false;
 
     if (!RunResolutionFunction(cx, reject, reason, RejectMode, promiseObj))
@@ -351,7 +361,8 @@ ResolvePromiseInternal(JSContext* cx, HandleObject promise, HandleValue resoluti
         JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
                                   JSMSG_CANNOT_RESOLVE_PROMISE_WITH_ITSELF);
         RootedValue selfResolutionError(cx);
-        MOZ_ALWAYS_TRUE(GetAndClearException(cx, &selfResolutionError));
+        if (!MaybeGetAndClearException(cx, &selfResolutionError))
+            return false;
 
         // Step 6.b.
         return RejectMaybeWrappedPromise(cx, promise, selfResolutionError);
@@ -364,7 +375,7 @@ ResolvePromiseInternal(JSContext* cx, HandleObject promise, HandleValue resoluti
     // Step 9.
     if (!status) {
         RootedValue error(cx);
-        if (!GetAndClearException(cx, &error))
+        if (!MaybeGetAndClearException(cx, &error))
             return false;
 
         return RejectMaybeWrappedPromise(cx, promise, error);
@@ -899,9 +910,7 @@ PromiseReactionJob(JSContext* cx, unsigned argc, Value* vp)
         args2[0].set(argument);
         if (!Call(cx, handlerVal, UndefinedHandleValue, args2, &handlerResult)) {
             resolutionMode = RejectMode;
-            // Not much we can do about uncatchable exceptions, so just bail
-            // for those.
-            if (!cx->isExceptionPending() || !GetAndClearException(cx, &handlerResult))
+            if (!MaybeGetAndClearException(cx, &handlerResult))
                 return false;
         }
     }
@@ -978,7 +987,7 @@ PromiseResolveThenableJob(JSContext* cx, unsigned argc, Value* vp)
     if (Call(cx, then, thenable, args2, &rval))
         return true;
 
-    if (!GetAndClearException(cx, &rval))
+    if (!MaybeGetAndClearException(cx, &rval))
         return false;
 
     FixedInvokeArgs<1> rejectArgs(cx);
@@ -1321,9 +1330,7 @@ PromiseObject::create(JSContext* cx, HandleObject executor, HandleObject proto /
     // Step 10.
     if (!success) {
         RootedValue exceptionVal(cx);
-        // Not much we can do about uncatchable exceptions, so just bail
-        // for those.
-        if (!cx->isExceptionPending() || !GetAndClearException(cx, &exceptionVal))
+        if (!MaybeGetAndClearException(cx, &exceptionVal))
             return nullptr;
 
         FixedInvokeArgs<1> args(cx);
@@ -2125,13 +2132,9 @@ js::CreatePromiseObjectForAsync(JSContext* cx, HandleValue generatorVal)
 MOZ_MUST_USE bool
 js::AsyncFunctionThrown(JSContext* cx, Handle<PromiseObject*> resultPromise)
 {
-    // Not much we can do about uncatchable exceptions, so just bail.
-    if (!cx->isExceptionPending())
-        return false;
-
     // Step 3.f.
     RootedValue exc(cx);
-    if (!GetAndClearException(cx, &exc))
+    if (!MaybeGetAndClearException(cx, &exc))
         return false;
 
     if (!RejectMaybeWrappedPromise(cx, resultPromise, exc))