Removing of threepid is not supported

[JOJ0]

From what I understand of the docs and my tests, this option does not allow to remove/override the existing 3pids, only to add more:

-t, --threepid <threepid>

Add a third-party identifier. [...]

Originally posted by @n-peugnet in #100 (comment)

[JOJ0]

Actually there are several issues with user modify --threepid

• It does not add threepid, it replaces ALL existing threepids with those passed as --threepid options
• It seems to only be possible to pass exactly one email address and one msisdn entry via synadm. I couldn't get multiple email addresses to work....not sure if the API does not accept that....further investigation required. The API docs are unclear about that https://matrix-org.github.io/synapse/latest/admin_api/user_admin_api.html#create-or-modify-account
• The documentation/--help is wrong, it states "add threepids", but scould be "replace threepids"
• It is not possible to pass something that says "clear all threepids"

As a workaround @n-peugnet, you could remove ALL threepids by issuing a plain request to the API using the raw command: https://synadm.readthedocs.io/en/latest/synadm.cli.raw.html

synadm -vv raw v2/users/@testuser1:yourdomain.org -m put --data '{"threepids":""}'

[JOJ0]

Some testing reveals that the second bulletpoint in the list above is indeed a bug within synadm. Adding several email adresses via a plain API call works! Both are added:

$ synadm -vv raw v2/users/@testuser1:peek-a-boo.at -m put --data '{"displayname":"New long testuser1 name","threepids":[{"medium":"email","address":"abc@123.com"},{"medium":"email","address":"def@456.com"}]}'
...
...
...
DEBUG {"displayname":"New long testuser1 name","threepids":[{"medium":"email","address":"abc@123.com"},{"medium":"email","address":"def@456.com"}]}
INFO  Querying put on https://peek-a-boo.at/_synapse/admin/v2/users/@testuser1:peek-a-boo.at
admin: false
appservice_id: null
avatar_url: null
consent_server_notice_sent: null
consent_ts: null
consent_version: null
creation_ts: 1573653091
deactivated: false
displayname: New long testuser1 name
erased: false
external_ids: []
is_guest: 0
last_seen_ts: null
locked: true
name: '@testuser1:peek-a-boo.at'
shadow_banned: false
threepids:
- added_at: 1699885788372
  address: def@456.com
  medium: email
  validated_at: 1699885788372
- added_at: 1699885821397
  address: abc@123.com
  medium: email
  validated_at: 1699885821397
user_type: support