1261457 - Rich text editor fails because requests to about:blank are blocked

Status: VERIFIED FIXED

(Firefox for iOS :: General, defect)

Description

[Aaron Train [:aaronmt]]

Visit (you'll need to create or connect an account)  

http://forums.macrumors.com/forums/ios-9.183/create-thread

Attempt to invoke focus to the thread body field. Nothing happens.

This was reported from Maria. This is not reproducible in Safari (made a mistake yesterday when testing this).

Noticed that in Safari/Desktop there's a formatting toolbar visible that's perhaps erring out in Firefox on iOS. 

Can this be web inspected remotely to check for errors?

Comment 1

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

I did a little bit of research: when I open the above URL in a minimal app that just has a WKWebView embedded without any of the infrastructure that Firefox adds, things work as expected.

So we need to narrow down what in Firefox causes this. My guess is that this is most likely related to some UserScript that we inject.

Comment 2

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

The problem persists after disabling all user content scripts. Not sure what is going on here yet.

Comment 3

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Also, not much useful in the web console.

Comment 4

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Attachment: PR: https://github.com/mozilla/firefox-ios/pull/1703

This patch adds a special case for `about:blank` to the 'should we load this url' decision handler.

It looks like `about:blank` is used to reset an iframe. We used to load these, but after https://github.com/mozilla/firefox-ios/pull/1576 (Bug 1251507 - Safari parity for url and scheme handling) we started to ignore them. That was a mistake :-/

This patch simply special cases `about:blank` and lets the `WKWebView` load them.

Comment 5

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

I have marked this with losing-users because we know of at least two cases where people have said 'i cannot use this because i cannot use some website anymore'.

Comment 6

[Brian Nicholson (:bnicholson)]

Comment on attachment 8740236 [details] [review]
PR: https://github.com/mozilla/firefox-ios/pull/1703

LGTM!

Comment 8

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Also, for reference, when you create a frame without a src, it defaults to about:blank. If we block that then page load events are never fired. Which breaks things that depend on this behaviour.

Comment 9

[Aaron Train [:aaronmt]]

Are we taking this patch on 4.0?

Comment 10

[Catalin Suciu [:csuciu]]

Verifying this as fixed on build 4.0.0b5