1428302 - Remove window.sidebar

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, task, P3)

Description

[David Bruant]

Rising from the ashes of bug 862147, the return of window.sidebar

> Telemetry data shows that window.sidebar is accessed by about 1.62% of page loads, that's too high to remove.

https://bugzilla.mozilla.org/show_bug.cgi?id=862147#c47

Standard discussion: https://github.com/whatwg/html/issues/3325

Comment 2

[Tom S [:evilpie]]

Telemtry still seems to show a relative high rate of access to this property: https://mzl.la/32GgRiQ. Probably some kind of browser detection. Should we try removing it Nightly?

Comment 3

[Anne (:annevk)]

Yeah, putting this behind a preference and disabling it on Nightly/early Beta sounds good.

Comment 4

[janestrapper]

It's not safe to remove window.sidebar at all. Yeah, this is used for browser detection, as always on Browserhacks, which explains its high internet usage. It is clear that if we remove that, a lot of sites will break.

Comment 5

[Emilio Cobos Álvarez (:emilio)]

(In reply to janestrapper from comment #4)

It's not safe to remove window.sidebar at all. Yeah, this is used for browser detection, as always on Browserhacks, which explains its high internet usage. It is clear that if we remove that, a lot of sites will break.

Citation needed. Browserhacks mentions a lot of hacks that are not up-to-date anymore (like appearance or moz-tree-row-based hacks). Looking at telemetry it seems like usage is ~0, and we've gotten no issues reported in 11 months. Kagami, do you think we should proceed?

Comment 6

[Emilio Cobos Álvarez (:emilio)]

Hmm, I lie, it's more like ~0.5% (link) which is non-trivial. Then again if usages are like the ones in bug 1768345 (causing compat issues rather than fixing them) maybe it's worth a try. It's been disabled for 11 months on Nightly / early-beta after all.

Comment 7

[Kagami Rosylight [:saschanaz] (they/them) (OOO until Dec 11)]

Agreed, I believe many of existing browser detection cases are now invalid. I'll write a patch to disable it.

Comment 8

[janestrapper]

See Bug 1769458.

Comment 9

[Thomas Wisniewski [:twisniewski]]

We will be monitoring for site breakage here, as there are signs that it might be bad to both keep or remove sidebar, from a webcompat perspective. But for now, we'll unset the webcompat priority flag on this bug until we have more info.

Comment 10

[Gregory Pappas [:gregp]]

Attachment: Bug 1428302 - Remove window.sidebar

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/78a88f877440
Remove window.sidebar r=webidl,saschanaz

Comment 12

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/78a88f877440

Comment 13

[Hamish Willee]

FF119 docs work for this can be tracked in https://github.com/mdn/content/issues/29306. Note that compatibility shows the removal in 102 when the feature was disabled behind a flag (that's how things are done when preferences are removed at end of feature life)