Trailing whitespace for usernames not removed

[sbg97]

Steps to reproduce

1. I made an account. Ex Username: "test" Password: "test"
2. Sign into the account with Username: "test " Password: "test"

Notice the trailing whitespace. This can be added automatically without the user noticing if you use autocorrect to complete your name.

Outcome

What did you expect?

I would expect the trailing whitespace to be automatically removed before processing since I'm pretty sure usernames can't have trailing whitespace.

What happened instead?

I get a popup saying "Invalid username or password"

Your phone model

moto g power

Operating system version

Android 11

Application version and app store

1.4.34 installed from F-Droid

Homeserver

Synapse

Will you send logs?

No

Are you willing to provide a PR?

No

[mnaturel]

Thanks for raising the issue. I guess we should add a verification on the username field like we do on the signup screen to warn about invalid characters.

[ByeongsuPark]

Hi, I'd like to take this issue.
Before that, I have a question about this issue's solution.
How about adding trim to the username input?
Considering that autocomplete is for the user's convenience, Adding a verification on the username's field as we do on the signup screen to warn about invalid characters leads to the user's inconvenience because it requires the user to do further action like deleting whitespace which is not needed if we just trim the user's input

[mnaturel]

Hi, I'd like to take this issue. Before that, I have a question about this issue's solution. How about adding trim to the username input? Considering that autocomplete is for the user's convenience, Adding a verification on the username's field as we do on the signup screen to warn about invalid characters leads to the user's inconvenience because it requires the user to do further action like deleting whitespace which is not needed if we just trim the user's input

Hi @ByeongsuPark, adding a trim to remove any trailing whitespace is okay as solution. I think it should be done when pressing the signin button on app side. I guess we should also add it on SDK side so that every client benefits from this.

I have done some checks and it seems this trim was done in the previous version of the signin screen. Plus, I have also checked the Matrix specs about userId and whitespace is not allowed on any server so it should not block anyone from signin.