1669545 - Show internal blocked reason instead of only "Blocked" when there is no valuable blocking reason

Status: RESOLVED FIXED

(DevTools :: Netmonitor, enhancement)

Description

[Alexandre Poirot [:ochameau]]

The following code, listening to http-on-stop-request always assumes the request is blocked if httpActivity.owner isn't set. But in the current state of the netmonitor, there is a couple of cases where the request is fully complete and we receive this http-on-stop event.

  _httpStopRequest: function(subject, topic) {
    ...
    const httpActivity = this.createOrGetActivityObject(channel);
    if (httpActivity.owner) {
      // Try extracting server timings. Note that they will be sent to the client
      // in the `_onTransactionClose` method together with network event timings.
      httpActivity.owner.addSeverTimings(serverTimings);
    } else {
      // If the owner isn't set we need to create the network event and send
      // it to the client. This happens in case where the request has been
      // blocked (e.g. CORS) and "http-on-stop-request" is the first notification.
      this._createNetworkEvent(subject, {
        blockedReason: reason,
        blockingExtension: id,
      });

The issue here comes from the else branch, which always assumes the request is blocked.

It is quite easy to reproduce with fission and navigating between two distinct origins. A brand new NetworkObserver is instantiated for each new navigation. And by the time the NetworkObserver start listening a few requests already started, so that we only receive the http-on-stop event. But all the requests are fully valid and complete, there only miss the owner attribute which is set by an event fired ealier, but missed by the new NetworkObserver.

Also, this code highlight another issue. A few requests failed, but we aren't receiving any particular blocking reason. reason is set to 0. But the request failed for some reason. We should try to communicate this reason. channel.status contains an error code. This can be cryptic, but it would certainly help us and platform developer understand netmonitor limitations/races!

Comment 1

[Alexandre Poirot [:ochameau]]

Attachment: Bug 1669545 - [devtools] Print internal error codes instead of only "Blocked" when there is not explicit blocking reason.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b8c0746ee199
[devtools] Print internal error codes instead of only "Blocked" when there is not explicit blocking reason. r=Honza

Comment 3

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/b8c0746ee199