crypto-browser example not working when using Dendrite

[trancee]

Background information

• Dendrite version or git SHA: 0.9.0
• Monolith or Polylith?: Monolith
• SQLite3 or Postgres?: SQLite3 and Postgres
• Running in Docker?: Yes
• go version:
• Client used (if applicable): https://github.com/matrix-org/matrix-js-sdk/blob/develop/examples/crypto-browser/olm-device-export-import.html

Description

• What is the problem: When following the instructions of the official example for the crypto-browser, the difference to running a Synapse and Dendrite comes to light. While it works as intended with Synapse, Dendrite will instead forever-loop the last step. After restarting the browser and doing the last step again, it works but it never decrypts the message.
• Who is affected: Anyone using Dendrite instead of Synapse
• How is this bug manifesting: By going through the steps
• When did this first appear: I just tested this last week

Steps to reproduce

• follow all the steps of the crypto-browser
• the last step will forever-loop

It would be great if Dendrite works the same way as Synapse, or at least give instructions on how to make this work with Dendrite as well.

Even better would be a vanilla JS example for e2ee using Dendrite.

[kegsay]

Thanks for this, we'll consider adding this client to our CI to ensure it actually works.