Ember-Inspector dev-tools add-on failing to open in Firefox Nightly and Developer Edition

Add-ons Development
#1

I am helping resolve some bugs in the ember-inspector add-on as a contributor and there have been some recent issues running the add-on in Firefox Nightly (62.0a1) and Developer Edition (61.0b13) versions. The add-on currently functions correctly in the standard version of Firefox (60.0.2).

When clicking on the add-on in the dev-tools panel the error that appears in the browser console is as follows:
Error: Unknown event: ["devtools.main", "enter", "webext-devtools-panel-ember-inspector_emberjs_com-357-0"] telemetry.js:627:5

This error seems to point to the Services.telemetry.recordEvent() function call in the below:

recordEvent(category, method, object, value, extra) {
  // Only string values are allowed so cast all values to strings.
  for (let [name, val] of Object.entries(extra)) {
    val = val + "";
    extra[name] = val;  

    if (val.length > 80) {
      const sig = `${category},${method},${object},${value}`;

      throw new Error(`The property "${name}" was added to a telemetry ` +
                    `event with the signature ${sig} but it's value ` +
                    `"${val}" is longer than the maximum allowed length ` +
                    `of 80 characters\n` +
                    `CALLER: ${this.getCaller()}`);
    }
  }
  Services.telemetry.recordEvent(category, method, object, value, extra);
}

I am looking for some assistance in determining the root cause, as I have been unable to find a stack trace for this error when debugging or observing the browser console.

Thank you very much for the assistance.

#2

It is rather concerning if the failure to send a telemetry event can break an extension. Does it work with telemetry fully disabled then?

#3

Thank you for the follow-up. I must admit, I did not know that it could be disabled. How do I disable it?

Also, I should have mentioned that when adding the add-on temporarily during development, it functions correctly in all Firefox versions.

#4

See https://support.mozilla.org/en-US/questions/1197144 resp. https://support.mozilla.org/en-US/kb/share-data-mozilla-help-improve-firefox

That then sounds like some load-order issue with the extension.

#5

Greatly appreciated. I will definitely try disabling telemetry.

That definitely could be likely. By chance, do you know what might have changed in the newer versions of Firefox? The extension did not have this issue in pre-61.0 versions. I just want make sure I can target the correct adjustments.

#6

I tried turning telemetry fully off, however, toolkit.telemetry.enabled is locked to true for nightly, dev, and beta versions. This seemed to keep me from fully getting telemetry out of the way. The current release version of Firefox, in which the add-on functions, has toolkit.telemetry.enabled locked to false.

After doing some further digging I found that the in the above error the webext-devtools-panel-ember-inspector_emberjs_com-357-0 corresponds to the object argument which is passed to Services.telemetry.recordEvent(category, method, object, value, extra);. From what I can tell, this seems to be why the error is thrown.

When referencing the Mozilla Source Tree Docs for the telemetry events API at the link below I found:

Throws if the combination of category, method, and object is unknown.

https://firefox-source-docs.mozilla.org/toolkit/components/telemetry/docs/telemetry/collection/events.html?highlight=recordevent#the-api

When referencing the telemetry events page at about:telemetry#events-tab add-ons typically have an acceptable object value of other.

Unfortunately, I am unsure of where the specific object value of webext-devtools-panel-ember-inspector_emberjs_com-357-0 is being generated. When temporarily adding the add-on in development, the object value is correctly other.

By chance do you have any further insights into the above details or recommended references? Is the above indicative of the load-order issue you mentioned? Thank you very much for the assistance.