Displayed formatted_body is erroneously parsed as markdown: code review and potential fix

[cloudrac3r]

A minimum example to reproduce is an event with "formatted_body": "*test*". Desktop correctly displays this as *test* (no italics). Element Android incorrectly displays this as test (italics).
The issue has already been described effectively in issue #350 and in issue #1375.
#3580 is caused by this issue. Sending a message with the content \*test\* from Element Android will create an event that exhibits the problem.

I believe the source of the issue is here: HTML messages are rendered by putting them into Markwon. That's what the htmlRenderer is. However, Markwon renders both HTML and Markdown. So any Markdown present in the formatted_body will be displayed again, which is exactly the issue we're seeing. https://github.com./vector-im/element-android/blob/ebee66cfafd6e9a0b31b5e992d22011f30271309/vector/src/main/java/im/vector/app/features/home/room/detail/timeline/factory/MessageItemFactory.kt#L606

A fix would be to disable the default Markdown features of Markwon, leaving it to only handle the HTML using the HTML plugin. It might not be obvious how to do this, but luckily, Markwon has an example that shows exactly how. https://github.com./noties/Markwon/blob/72f6174db9530d2fab976b75a1451b63740390f7/app-sample/src/main/java/io/noties/markwon/app/samples/NoParsingSample.java
This line disables inline parsing (like bold and italics): .usePlugin(MarkwonInlineParserPlugin.create(MarkwonInlineParser.factoryBuilderNoDefaults()))
This line disables block parsing (like lists and quotes): builder.enabledBlockTypes(Collections.emptySet());
So you'd just have to add this to the Element Android code, in whatever your htmlRenderer is doing.

I'm not experienced enough with Element Android's code to be able to propose a fix that is integrated into the code, but I am able to run custom code on my cell phone, so I can test any full solutions if that would help.

Thank you so much! Here's hoping we can fix this so that people can send messages that contain asterisks. ☺️

[tusooa]

Can confirm.

[ouchadam]

fixed by #6357 and will be available in 1.4.26