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Maniphest T285204

Can't remove lines with syntax highlight on Android
Closed, ResolvedPublic2 Estimated Story PointsBUG REPORT
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Description

How to reproduce:

  • From a mobile device go to a template page, i.e. en:Template:Template sandbox
  • Change to desktop view if necessary.
  • Edit it
  • Activate syntax highlight with the pencil button, if necessary.
  • Insert new lines anywhere.
  • Try to remove them with backspace key.

Actual results:

  • Cursor moves out of edit box and it does nothing.

Reported with:

  • Chrome 91 on Android 10
  • Chrome 90 on Android 11
  • Chrome 91 on Android Oreo

Initial reporter suspects it happens since the introduction of line numbering feature.

Related Objects

Event Timeline

Vriullop created this task.Jun 21 2021, 7:53 AM
Restricted Application added a subscriber: Aklapper. · View Herald TranscriptJun 21 2021, 7:53 AM
Mainframe98 added a project: Wikipedia-Android-App-Backlog.Jun 21 2021, 9:10 AM
Aklapper removed a project: Wikipedia-Android-App-Backlog.Jun 21 2021, 11:54 AM

Hi, which editor software is being used? See https://www.mediawiki.org/wiki/Editor

This looks unrelated to mobile apps but seems to be about web browsers.

Vriullop added a comment.Jun 21 2021, 5:28 PM

The WikiEditor. With 2017 wikitext editor it does not work either, but it has a different behavior due to T212680 or related problems. I think syntax highlight by extension CodeMirror is only used with these editors.

Aklapper added projects: SyntaxHighlight, Browser-Support-Android-Google-Chrome.Jun 22 2021, 7:29 AM
thiemowmde added subscribers: thiemowmde, WMDE-Fisch.Jun 22 2021, 10:10 AM

FYI, I can not reproduce this in Chrome 91 on Android 10.

@Vriullop, where was the "initial report" posted? On a wiki? Can you please provide a link?

Vriullop added a comment.Jun 22 2021, 11:40 AM

Initial report in Catalan at https://ca.wikipedia.org/wiki/Tema:W9w073tmxykojcq4

thiemowmde added projects: MediaWiki-extensions-CodeMirror, WMDE-TechWish, WMDE-TechWish-Sprint-2021-06-23.Jun 23 2021, 8:28 AM
thiemowmde set the point value for this task to 2.
Restricted Application added a project: Community-Tech. · View Herald TranscriptJun 23 2021, 8:28 AM
WMDE-Fisch claimed this task.Jun 23 2021, 10:41 AM
WMDE-Fisch moved this task from Sprint Backlog to Doing on the WMDE-TechWish-Sprint-2021-06-23 board.

First revelation to this from my side:

  • Some mobile browser will always return a 229 keycode on keydown and keyup events. So if you try do use one of these in your code you can not rely on the keycode. That's at least whats happening on my mobile device. Instead you should try to use keypress, that will always give the right keycode. [1]
  • There's this line in the CodeMirror codebase, where a backspace-keypress is thrown away [2]
  • And one line, where there's a backspace - keydown manually triggered for Android Chrome [3]

[1] https://social.msdn.microsoft.com/Forums/en-US/d9ac5d52-55f5-4e8f-b074-22323834a09c/keydown-event-always-returns-keycode-229?forum=vssmartdevicesvbcs
[2] https://gerrit.wikimedia.org/g/mediawiki/extensions/CodeMirror/+/daeaae012cd637ff34978d5410b9cd252373e9d4/resources/lib/codemirror/lib/codemirror.js#7252
[3] https://gerrit.wikimedia.org/g/mediawiki/extensions/CodeMirror/+/daeaae012cd637ff34978d5410b9cd252373e9d4/resources/lib/codemirror/lib/codemirror.js#8994

thiemowmde added a comment.Jun 23 2021, 11:51 AM

While this is definitely related, both changes happened in 2017.

Die Chrome's behavior change?

WMDE-Fisch moved this task from Doing to Demo on the WMDE-TechWish-Sprint-2021-06-23 board.Jun 24 2021, 10:38 AM

I played with this for a while now including trying to understand it better and fix it. The bug is obviously upstream in the library since it also appears on the demo page for CodeMirror[1]. There are also already some tickete for issues around mobile support including one umbrella ticket that lists the backspace bug[2].

It can be expected, that most of these issues will not be dealt with in version 5 of CodeMirror and will hopefully be fixed with version 6. Until then I guess we could thinking about disabling the feature for mobile browsers.

[1] e.g.: https://codemirror.net/demo/marker.html
[2] https://github.com/codemirror/CodeMirror/issues/6145

WMDE-Fisch mentioned this in T285660: CodeMirror: Disable line numbers for mobile devices.Jun 28 2021, 10:11 AM
WMDE-Fisch closed this task as Resolved.Jul 6 2021, 11:11 AM

This will be solved temporary by disabling the feature for mobile devices in T285660: CodeMirror: Disable line numbers for mobile devices.
The proper solution should be applied by doing T259059: Upgrade to CodeMirror 6.

I will close this ticket for now.

WMDE-Fisch moved this task from Demo to Done on the WMDE-TechWish-Sprint-2021-06-23 board.Jul 6 2021, 11:41 AM
WMDE-Fisch moved this task from Proposed to Done on the WMDE-TechWish board.Jul 20 2021, 9:45 AM
Izno moved this task from Backlog to Done on the MediaWiki-extensions-CodeMirror board.Aug 19 2021, 7:06 PM
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