1353897 - Stop requesting preference fronts on toolbox close

Status: RESOLVED FIXED

(DevTools :: Framework, enhancement, P1)

Description

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

A preference front getter is referenced in the toolbox close, triggering listTabs and more when the toolbox is on its way out.

We should skip all of this in the base (when no prefs are touched).

Comment 1

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

Attachment: Bug 1353897 - Only destroy preference front if used.

The toolbox can get a preference front for toggling various prefs on the server.
The toolbox destruction code path was written in such a way that it would
request a preference front during toolbox destroy, only to immediately destroy
the front right after.  This is extra painful, since we send a `listTabs`
request and other fun things as part of this.

With this chance, we cache the preference front when it is first used, and we
only attempt to destroy it if it was previously used.

Review commit: https://reviewboard.mozilla.org/r/126962/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/126962/

Comment 2

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

https://treeherder.mozilla.org/#/jobs?repo=try&revision=ae58f69f56e76f1a4d8b1557394355fa685d53fe

Comment 3

[Alexandre Poirot [:ochameau]]

Comment on attachment 8855058 [details]
Bug 1353897 - Only destroy preference front if used.

https://reviewboard.mozilla.org/r/126962/#review129842

Good catch, thanks!

It is interesting to see that this pattern is quite often necessary.
Something that needs to be lazily instanciate.
But not just lazy, optionally lazy. We enventually want to do something only if it has been instanciated.
I ended up landing various patch in the inspector for that.
We were wondering with jdescottes if we could come up with some common helper, similar to loader.lazyGetter, to help implement this pattern and ease identifying it all over the place.

::: commit-message-b0432:9
(Diff revision 1)
> +The toolbox destruction code path was written in such a way that it would
> +request a preference front during toolbox destroy, only to immediately destroy
> +the front right after.  This is extra painful, since we send a `listTabs`
> +request and other fun things as part of this.
> +
> +With this chance, we cache the preference front when it is first used, and we

s/chance/change/

Comment 4

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

Hmm, yes, a common helper sounds nice for this idiom!

Comment 5

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

Comment on attachment 8855058 [details]
Bug 1353897 - Only destroy preference front if used.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/126962/diff/1-2/

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a484b0cfa3ad
Only destroy preference front if used. r=ochameau

Comment 7

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/a484b0cfa3ad