/invite API does not fill displayname field

[t3chguy]

Background information

• Dendrite version or git SHA: dendrite-demo-pinecone:main
• SQLite3 or Postgres?: sqlite3
• Running in Docker?: yes
• go version: dendrite-demo-pinecone:main
• Client used (if applicable): element-web

Description

• What is the problem: DM rooms with pending invites show up with a userId instead of display name
• Who is affected: Most people seemingly
• How is this bug manifesting: /sync returns less helpful data
• When did this first appear: Unclear

Steps to reproduce

• Invite an existing user with a display name
• Observe your invite event has no displayname field

The spec does not explicitly say to do this, maybe it ought to. Synapse does this. Without this invites are significantly more confusing to the end user given that they may have invited via the User Directory graphically, so never saw the MXID, now only see the MXID until the user joins.

SynapseTrace.zip
DendriteTrace.zip