1443550 - Blank debugger when connecting to FF for Android in Firefox 59

Status: RESOLVED FIXED

(DevTools :: Debugger, defect, P1)

Description

[Julian Descottes [:jdescottes]]

STRs:
- enable USB remote debugging on android phone
- open webide
- connect to phone
- select any tab 
- select debugger

Debugger is blank. When open the browser toolbox, the following exception is found:

"onPacket threw an exception: Error: Server did not specify an actor, dropping packet: {"error":"unknownError","message":"error occurred while processing 'listWorkers: TypeError: Ci.nsIWorkerDebugger is undefined\nStack: onListWorkers@resource://devtools/shared/base-loader.js -> resource://devtools/server/actors/tab.js:48:87\nonPacket@resource://devtools/server/main.js:141:212\nreceiveMessage@resource://devtools/shared/transport/transport.js:43:183\nLine: 48, column: 87"}
Stack: onPacket@resource://devtools/shared/base-loader.js -> resource://devtools/shared/client/debugger-client.js:857:9
_onJSONObjectReady/<@resource://devtools/shared/base-loader.js -> resource://devtools/shared/transport/transport.js:483:11
exports.makeInfallible/<@resource://devtools/shared/ThreadSafeDevToolsUtils.js:109:14
exports.makeInfallible/<@resource://devtools/shared/ThreadSafeDevToolsUtils.js:109:14
Line: 857, column: 9"

Comment 1

[Julian Descottes [:jdescottes]]

I assumed this was a backward compatibility issue, but debugging FF for android is broken in FF59.

The new-debugger debugger always tries to fetch workers (https://github.com/devtools-html/debugger.html/blob/76006381eb63063a8a334097bfbd5c9bf2175224/src/actions/navigation.js#L59) calling listWorkers on the tab actor, which crashes at https://searchfox.org/mozilla-central/rev/c217fbde244344fedfd07b57a740c694a456dbca/devtools/server/actors/tab.js#635

Comment 2

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

I believe the core platform issue is just that XPCOM interfaces for workers aren't packaged on Fennec, which is likely just an oversight.

The Fennec package-manifest.in[1] does not have entry for `dom_workers.xpt`, while the Firefox one[2] does.

Of course, there are still separate issues about how to workaround it in the meantime while existing Fennec versions, as well as the general DevTools errors handling we also discussed today.

[1]: https://searchfox.org/mozilla-central/source/mobile/android/installer/package-manifest.in
[2]: https://searchfox.org/mozilla-central/rev/c217fbde244344fedfd07b57a740c694a456dbca/browser/installer/package-manifest.in#223

Comment 3

[Julian Descottes [:jdescottes]]

Attachment: Bug 1443550 - package dom_workers.xpt on Fennec to enable worker debugging;

dom_workers.xpt was originally added to Firefox's package-manifest.in
in Bug 757133 (https://hg.mozilla.org/mozilla-central/rev/d5fcb5f05f03).

Adding it to Fennec will allow us to list and debug workers on this platform.

Review commit: https://reviewboard.mozilla.org/r/230448/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/230448/

Comment 4

[Julian Descottes [:jdescottes]]

Attachment: Bug 1443550 - include actorId in unknown error packet from DevTools server

Review commit: https://reviewboard.mozilla.org/r/230450/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/230450/

Comment 5

[Julian Descottes [:jdescottes]]

As mentioned by :jryans, the root fix is to package the worker debugging library with Fennec. When it comes to client workarounds, I have opened two debugger.html PRs to discuss the best approach:
- https://github.com/devtools-html/debugger.html/pull/5763
- https://github.com/devtools-html/debugger.html/pull/5761

I attached a second changeset here to improve catching errors from actors, but this should move to its own bug.

Comment 6

[Julian Descottes [:jdescottes]]

Comment on attachment 8961587 [details]
Bug 1443550 - package dom_workers.xpt on Fennec to enable worker debugging;

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/230448/diff/1-2/

Comment 7

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Comment on attachment 8961587 [details]
Bug 1443550 - package dom_workers.xpt on Fennec to enable worker debugging;

https://reviewboard.mozilla.org/r/230448/#review235952

Thanks, this looks correct to me. :)

I also checked for related interfaces like service workers and push.  It seems they are in `dom_base`, which is already packaged for Fennec.

Comment 8

[Julian Descottes [:jdescottes]]

Thanks for the careful check! Try looks relatively happy https://treeherder.mozilla.org/#/jobs?repo=try&revision=b05f06a136b495f93d7dadee14922eb7b700ee82

As discussed on https://github.com/devtools-html/debugger.html/pull/5761, I will focus on uplifting the debugger workaround rather than the android change for now.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/86ecbe9ad857
package dom_workers.xpt on Fennec to enable worker debugging;r=jryans

Comment 10

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/86ecbe9ad857