App stopped working completely, unhandled promise rejection 'browserName'

[Siilwyn]

Description

I've been using Riot for a long time but it suddenly stopped working. I tried clearing my browser data and opening Riot in private mode to no avail.

Steps to reproduce

1. Open the web app
2. Get stuck on a blank loading page

This is what's seen in the console:

Version information

• Platform: web (in-browser)
• Browser: Firefox 53.0.3
• OS: Ubuntu
• URL: https://riot.im/app/

[MTRNord]

[sprintf] errors are related to i18n. Sounds like a broken language

[Siilwyn]

@MTRNord can I test that theory somehow? I'm using "English (US)".

[MTRNord]

@Siilwyn currently no Idea but normaly it says that a %(browserName)s is missing somewhere

[MTRNord]

@Siilwyn do you have any type of AdBlocker running? On my side Firefox and Chrome are working fine.

[Siilwyn]

Yes uBlock, just tried with all extensions disabled but that didn't work either.

[MTRNord]

@Siilwyn can you take a look at your Networking Tab in the Console if it is downloading a en_EN.json ? And if possible give a pastebin with the content.

[Siilwyn]

Yes, it's there. 200 OK.

[Siilwyn]

Just noticed I have the same problem in Chromium... I tried stepping through with the debugger but can't pinpoint where it goes wrong. After Counterpart.prototype.translate returns entry containing "%(appName)s via %(browserName)s on %(osName)s" it jumps to the tryCatch function inside runtime.js.

[MTRNord]

@Siilwyn I know where it fails but cannot reproduce it :/ I check some things to find a trace. Both Chrome and Firefox are working fine on my side

[MTRNord]

It could be that https://github.com/vector-im/riot-web/blob/24a5297fc8b38dce7790f98a3b25a29372e612db/src/vector/platform/WebPlatform.js#L163 Does not return a string which could cause it to fail.

[Siilwyn]

Yes that line returns undefined, it shouldn't throw an error right? I would assume it should fall back to an empty string or a default?

[kegsay]

I would hope that passing an undefined value to _t wouldn't cause the entire thing to fail, given how the equivalent ES6 template strings work regardless.

> s = {}
{}
> console.log(`hello ${s.foo}`)
hello undefined

[MTRNord]

@kegsay I guess that is a bug that should also be addressed to counterpart or sprintf-js

[kegsay]

matrix-org/matrix-react-sdk#1035 will fix this in all cases, then will close this issue.