1876924 - Treat "incognito":"split" as a warning instead of a hard error

Status: RESOLVED FIXED

(WebExtensions :: General, enhancement, P3)

Description

[Rob Wu [:robwu]]

When an extension has "incognito":"split" in manifest.json, Firefox refuses to load it, because it is not part of the enum at: https://searchfox.org/mozilla-central/rev/4cef3cd672243f7ae6d46103ca0ea7b253a74484/toolkit/components/extensions/schemas/manifest.json#122-127

In Chrome, "incognito":"split" is required if an extension wants to open extension tabs in incognito mode. In Firefox "incognito":"split" is not supported (bug 1380812), and tabs can be opened in private browsing mode (provided that the extension has access to it).

To avoid porting difficulties, we should accept "incognito":"split" value, and log a non-fatal warning instead of preventing the extension from loading.

To resolve this bug, it suffices to turn the enum type in a list of enum where the "split" value is annotated with "deprecated", similar to what was done in https://hg.mozilla.org/mozilla-central/rev/e676737b9689#l2.2 as part of bug 1370077. When we recognize "split" but do not support it, we just treat it as "incognito":"spanning".

Comment 1

[Rob Wu [:robwu]]

Attachment: Bug 1876924 - Accept manifest with "incognito":"split"

Comment 2

[Rob Wu [:robwu]]

(In reply to Rob Wu [:robwu] from comment #0)

To resolve this bug, it suffices to turn the enum type in a list of enum where the "split" value is annotated with "deprecated", similar to what was done in https://hg.mozilla.org/mozilla-central/rev/e676737b9689#l2.2 as part of bug 1370077. When we recognize "split" but do not support it, we just treat it as "incognito":"spanning".

I ultimately ended up using a different implementation, using "onError":"warn". The advantage of this to "deprecated" is that the fallback value ("spanning") is automatically selected instead of using the invalid value. This might also be a good strategy to use to resolve bug 1831417.

Comment 3

[Rob Wu [:robwu]]

After discussing with the team, there were concerns with silently treating "incognito":"split" as "incognito":"spanning". So the safest option to minimize risk while still supporting extensions, is to accept "incognito":"split" extensions, in non-private browsing mode only. So effectively "incognito": "not_allowed", optionally with a flag/pref to opt in to running the extension in private browsing mode.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1b4eeef2a14a
Accept manifest with "incognito":"split" r=rpl

Comment 5

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/1b4eeef2a14a

Comment 6

[Rob Wu [:robwu]]

Why was this classified as a task? It is an enhancement: previously extensions with incognito:split could not load at all in Firefox, now they can.

Despite this improvement, extension developers are encouraged to drop incognito:split from their manifest because otherwise the extension cannot be used in Firefox's private browsing mode.

Comment 7

[Pascal Chevrel:pascalc]

If dev-doc is needed for the release, as you just added to the bug, that indeed fits our enhancement definition.

Comment 8

[rbloor]

MDN content changes are ready for review:

• BCD "incognito": "split" support #23124
• Docs Document support for "incognito": "split" #33661