845245 - Remove support for -moz-border-image

Status: NEW

(Core :: CSS Parsing and Computation, task)

Comment 1

[Kohei Yoshino [:kohei]]

Posted the site compatibility doc: https://www.fxsitecompat.com/en-US/docs/2015/moz-border-image-will-be-removed/

Comment 2

[Thomas Wisniewski]

Is now a good time to finally remove the -moz prefix for border-image, or are there known reasons to keep it around for a bit longer?

Comment 3

[:Ms2ger (he/him; ⌚ UTC+1/+2)]

None that I personally know of.

Comment 4

[Thomas Wisniewski]

Is it worth doing a telemetry run to be sure? I don't know if there's a way for telemetry to check if both the unprefixed and prefixed versions are part of the same rule (whichever one is used in the end), so I'd fear the results would be inaccurate...

Comment 5

[:Ms2ger (he/him; ⌚ UTC+1/+2)]

The telemetry would probably need custom code in nsCSSParser.cpp; I don't know enough to be of help with that. bsmedberg could probably help with the telemetry side.

Comment 6

[Thomas Wisniewski]

Benjamin, is there any light you can shed on how I would do telemetry to determine how many sites are using only -moz-border-image, rather than both it and its unprefixed version, border-image?)

Comment 7

[Benjamin Smedberg]

It would be possible to measure this per-pageload or documnet using bug 1297457, once that's done. Note that this doesn't measure per *site* though.

The question of whether this is a useful question to answer is one for you and the webcompat team to decide. I do think you should decide your criteria up front: what will you decide if 0.2% of our global population shows some unmatched -moz-border-image usage? Or 0.02% of pageloads, or whatever you decide to measure.