Message Editor pills only showing trailing `:`

[rekkisomo]

Description

When mentioning a room or user, the pill in the Message Editor does not show, and only shows the trailing :. Started happening out of nowhere.

Steps to reproduce

N/A

Describe how what happens differs from what you expected.

Instead of showing a user pill in the editor, it only shows a :. It also does not show pills in chat, an instead a blue link showing the username. Checked console, nothing shows up (even verbose) about the message editor or pills.

If it helps, backspacing the trailing space as well as the : reveals that the pill is technically there, as the placeholder for the message editor doesn't show until another backspace happens. When inspecting element, this shows:

<p data-key="55">
    <span data-key="56">
        <span data-offset-key="56:0">
            <span data-slate-zero-width="z">&#65279;</span>
        </span>
    </span>
    <span data-slate-void="true" data-key="60" contenteditable="false">
        <span data-slate-spacer="true" style="height: 0px; color: transparent; outline: none; position: absolute;">
            <span data-key="62">
                <span data-offset-key="62:0">
                    <span data-slate-zero-width="z">&#65279;</span>
                </span>
            </span>
        </span>
        <span contenteditable="false">
            <a href="https://[riot self-host url]/#/@danteotter:[...]" data-key="60"></a>
        </span>
    </span>
    <span data-key="61">
        <span data-offset-key="61:0">: </span>
    </span>
</p>

When mentioning a user

When message sends (if this error is important, hard to tell as it doesn't happen all the time.)

When sending a message containing @room (which does embed a pill to the Message Editor), vs mentioning a channel (which doesn't show anything, only a space)

Logs being sent: no

Version information

• Platform: web (in-browser) or desktop? Web

For the web app:

• Browser: Chrome (75.0.3770.100)
• OS: Windows
• URL: Private, Version 1.3.0.

[bwindels]

@rekkisomo How do you try to mention a user? By typing @name or Name in the composer? Or clicking on a name in the timeline? Or clicking on Mention in the user panel?

Removed the new-composer label as it doesn't seem related to that. It might be related to some refactoring wrt to pills to make them usable in the Edit history dialog though.

[rekkisomo]

It happens on any method of mentioning a user (@name in editor, clicking username in chat, etc.)