element-web: SSO sign-in uses unknown vector:// URL type

Description

Signing in to an internal chat server that uses SSO does not work as some of the browser-based flow is broken.

Steps to reproduce

• Start riot desktop application
• Click Sign in
• Click Change to use our internal server, click Next
• Click Sign in with single sign-on
• Browser (firefox) window opens with our internal SSO page, where I log in
• Get a new browser page with The application at vector is requesting full access to your <censored> Matrix account. If you don't recognise this address, you should close this browser window., plus a button with I trust this address
• Pressing the address button redirects the page to a URL reading vector://vector/webapp/?homeserver=...
• Browser gives error The address wasn’t understood

Describe how what happens differs from what you expected.

The browser should probably open the riot application with the verification info in the URL, but that doesn’t work, as the vector:// type isn’t understood… This issue seems similar, but it mentions a “riot://” URL, plus I’m not using the flathub version of the application.

Is there a way to manually give back the login URL to the riot-desktop application? I check the command-line params but don’t see a relevant option.

Version information

• Platform: desktop
• OS: Arch Linux
• Version: 1.5.13 (note: the latest available version in the Arch repos is currently 1.5.12, I updated the PKGBUILD locally and built it to check if the SSO updates in 1.5.13 helped with the issue, but they don’t)