896222 - Profiling should work in private browsing via obfuscating frames from private tabs

Status: RESOLVED WONTFIX

(DevTools :: Performance Tools (Profiler/Timeline), defect, P3)

Description

[Tetsuharu OHZEKI [:tetsuharu] (UTC+9)]

[environment]
* OSX 10.8.4
* http://hg.mozilla.org/mozilla-central/rev/bf73e10f5e54

[step to reproduce]
1. Open devtools profiler on tabs which is opened in private browsing mode.
2. Click the button to start profiling.

[Result]
* This error massage is shown in browser console
--------
[Exception... "Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) [nsIProfiler.StartProfiler]"  nsresult: "0x80040111 (NS_ERROR_NOT_AVAILABLE)"  location: "JS frame :: resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/actors/profiler.js :: ProfilerActor.prototype.onStartProfiler :: line 86"  data: no]
undefined @ resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js:756
--------
* each profile lists are displayed as "idle".

Comment 1

[Anton Kovalyov (:anton)]

Confirmed on the trunk build running on OS X Mountain Lion.

Comment 2

[Nils Maier [:nmaier]]

This is a direct outcome of bug 822135, and actually desired behavior.

The "UI" sucks, though, as there is no UI and not even an error message. I had to figure this out by looking to the console and then into the code.

Therefore, there should either be proper UI notifying the user that the profile is disabled while there is a private browsing window active, or the profiler should be available and just dump the samples when "last-pb-context-exited" like other components do.
I'd opt for the later, or at least a way to pref this off, as I was specifically trying to profile a code path in one of my extensions that only runs in private windows.

Benoit, I guess the ball is in your corner now?

Comment 3

[Benoit Girard (:BenWa)]

I'm ok with adding an option to force disable this safety measure but otherwise I rather just have it disable it instead of running the profiler in a crippled privacy mode without having a good way to warn the users.

I think the right fix here is to improve the UI to explain why the profiler is locked.

Comment 7

[Panos Astithas (he/him) [:past] (please ni?)]

It seems that sometimes profiling works in PBM. From IRC today:

1:41 PM <Tew> past - private window, performance started (and completed) successfully, http://i.imgur.com/jHsMzQz.png

Comment 8

[Jordan Santell [:jsantell] [@jsantell]]

If we can identify frames via content window in bug 1152400, we might be able to obfuscate only specific tabs so the perftools can still function in private browsing

Comment 10

[Greg Tatum [:gregtatum]]

Closing this bug as this is the desired behavior, and there are currently no plans to do the work to obfuscate the data.