Issue 4579 - Ignore runtime.lastError caused by wrapper

polyfill.js

Index: polyfill.js
===================================================================
--- a/polyfill.js
+++ b/polyfill.js
@@ -38,16 +38,22 @@
     "tabs.sendMessage",
     "tabs.update",
     "webNavigation.getAllFrames",
     "webRequest.handlerBehaviorChanged",
     "windows.create",
     "windows.update"
   ];
 
+  // Errors that occur only when we show an interest in the response from an

[Manish Jethani, 2017/10/19 10:13:23]

We should keep this array because there are more such errors.

[kzar, 2017/10/19 10:17:49]

Maybe a Set would be a better data structure to use?

I also wonder if we should export this, so it's transparent to the rest of the
code what we're ignoring. But I guess we can do that when it becomes necessary.

[Manish Jethani, 2017/10/19 10:24:46]

Regarding the error message itself, I should go back and check earlier Chrome
versions. I'll also include Ollie here to verify the behavior on Edge.

[Manish Jethani, 2017/10/19 10:30:32]

Good point, done.
Sounds like it might be a good idea, though I agree let's wait until it's
actually needed.

[Sebastian Noack, 2017/10/19 18:30:18]

We can easily turn it into an array, set or regexp when needed. But as long as
we only checking for a single string, I think we should not over-engineer our
data structures for some potential future use case.

But yeah, we should probably figure out the behavior (and error message if any)
on Microsoft Edge first.

[kzar, 2017/10/19 18:37:39]

Yea I'm pretty sure we all agree there, if we can just compare one string we
should do that instead.

[Sebastian Noack, 2017/10/19 22:08:31]

Ollie just confirmed, that on Microsoft Edge no error occurs if no response is
sent. So it seems this is the only error message string we have to check for.
Hence a Set or array seems unnecessary.

+  // API call.
+  const noFulfillmentErrors = [
+    "The message port closed before a response was received."
+  ];
+
   function wrapAPI(api)
   {
     let object = browser;
     let path = api.split(".");
     let name = path.pop();
 
     for (let node of path)
     {
@@ -71,17 +77,17 @@
       if (typeof args[args.length - 1] == "undefined")
         args.pop();
 
       return new Promise((resolve, reject) =>
       {
         func.call(object, ...args, result =>
         {
           let error = browser.runtime.lastError;
-          if (error)
+          if (error && !noFulfillmentErrors.includes(error.message))
             reject(error);
           else
             resolve(result);
         });
       });
     };
   }