Messages containing only digits followed by a period are invisible

[dkasak]

This only happens when the message is sent from Riot Web with Markdown input turned on, but Riot Web itself displays the message properly. The problem seems to be that it also produces a formatted_body containing an ordered list with a single empty item, which Riot Android then renders as an empty message.

This was tested on Riot Android 0.8.8.

[bmarty]

Bug confirmed

[bmarty]

(thanks for reporting)

[bmarty]

The pb is also present on iOS (element-hq/element-ios#1897)

[zeratax]

This seems related, but writing a message like:

`5. October 😊`

results in:

• mobile: •October �
• web: 1. October 😊

while desktop isn't technically a bug it's still probably not what users would expect to happen or necessarily understand why a date is being replaced by a different date.
I can create a separate issue for this for mobile and web if that's wanted.

[bmarty]

It's related to Markdown formatting, so, despite the huge inconvenient, we have to say it's a feature, not a bug...
Also note that 123456. will not be displayed correctly as well on Riot-Web

[dkasak]

I disagree, this is definitely a bug, but it's also not happening anymore on Riot Android 0.8.17 so it seems like it has been (inadvertently?) fixed! It now renders as 1., just like it should. I would argue it is still semantically incorrect, though, and that numbered lists with a single, empty item should be special-cased and not recognized as Markdown at all, but that is a Riot Web bug.

The wrong rendering of 123456. in Riot Web is a totally separate bug, judging by the result:

[zeratax]

Alright even if we don't care about markdown not being consistent and not doing what users probably would expect, I'm still very confused about the emoji getting mangled.

[bmarty]

I still have the issue with 1.. Maybe you have inadvertently disabled the markdown?

[dkasak]

I don't think so.

Riot Web:

Message source (as seen in Riot Web):

{
  "origin_server_ts": 1539892403760,
  "sender": "@dkasak:termina.org.uk",
  "event_id": "$15398924031747tJKKp:termina.org.uk",
  "unsigned": {
    "age": 71,
    "transaction_id": "m1539892405307.30"
  },
  "content": {
    "body": "1.",
    "msgtype": "m.text",
    "formatted_body": "<ol>\n<li></li>\n</ol>\n",
    "format": "org.matrix.custom.html"
  },
  "type": "m.room.message",
  "room_id": "!DCRUrRQxGhHTRwlYla:termina.org.uk"
}

Riot Android:

Message source (as seen in Riot Android):

Riot Web version: 0.16.5
Riot Android version: 0.8.17 (G-b155)

[dkasak]

So could this be reopened? It works in one client and it doesn't in another. It was also working in both clients for a bit as my screenshots show.

I also see a sensible workaround: don't consider empty lists as something the user intended and fall back on body in those cases. However, it might be more appropriate to fix it in Riot Web, such that it doesn't actually emit HTML at all when you type in ^[0-9]+\.\s*$ (or something like that) even in Markdown mode. In fact, this is what Riot Android does.

Should I open this issue on Riot Web?