mailbox – Dovecot common virtual folder for all users

I have the dovecot:

namespace {
  prefix = virtual/
  separator = /
 location = virtual:~/mail/virtual/
  list = yes
  inbox = no
  subscriptions = yes
  hidden = no
}
  • ONE USER ~/virtual/All/dovecot-virtual with:
*
-Trash/*

I hence get all the mail listed in that virtual folder.

Now I’d like this to work for all of them, and cannot find any doc on that.

I tried directing the namespace location towards /var/mail/virtual/
BUT once several users access it, it corrupts the index.
Hence I tried to add some index specific space:

namespace {
  prefix = virtual/
  separator = /
 location = virtual:/var/mail/virtual/:INDEX=~/mail/virtual
  list = yes
  inbox = no
  subscriptions = yes
  hidden = no
}

But it does not work and even blocks the folder reading update:
<129212>: Panic: file mail-index-sync.c: line 419 (mail_index_sync_begin_to2): assertion failed: (!index->syncing)

Is there any good way to do that without replicating the dovecot-virtual for each user ?

Thanks in advance