[BUG?] Dovecot 2.4.2 from Dovecot repo (RHEL 9) does not implement Sieve (properly/fully)

Hi all

Below is report of what I suspect is a bug arising in Dovecot 2.4.x regarding Sieve functionality after Pigeonhole functionality was folded into Dovecot/Dovecot-sieve. 

ISSUE:
======

I am building a new mail server on Rocky Linux 9.7 with Postfix 3.10 and Dovecot 2.4.2. The base installation & setup of Dovecot was OK with core functionality (Postfix interoperability and mail into virtual mail domain mailboxes no problem).

Once I had the base setup done I started with Sieve functionality:

1) Incoming mail marked as SPAM by Rspamd auto moved into /Junk
2) Mail manually moved in/out of /Junk handed to Rspamd for training as SPAM/HAM

This consistantly failed - the first issue I found was Dovecot failing to restart and `dovecot -n` reporting fatal errors related to sieve — section not found etc. etc.

>From my reading previously I knew I needed to install `dovecot-sieve` and it was installed before I started working on Sieve functionality. I also saw `dovecot-pigeonhole` but I seemed to read that (version >= 2.4) the functionality for that had been included in `dovecot-sieve` **and** there was no Pigeonhole included in the Dovecot 2.4.2 repo — also if I tried to install it I got errors of course because of the version mismatch, and it was not in the dovecot-2.4-latest repo.

```
# dnf info dovecot-pigeonhole
Last metadata expiration check: 1:21:15 ago on Fri 06 Mar 2026 08:05:08.
Available Packages
Name         : dovecot-pigeonhole
Epoch        : 1
Version      : 2.3.16
Release      : 15.el9
Architecture : x86_64
Size         : 371 k
Source       : dovecot-2.3.16-15.el9.src.rpm
Repository   : appstream
Summary      : Sieve and managesieve plug-in for dovecot
URL          : https://www.dovecot.org/
License      : MIT and LGPLv2
Description  : This package provides sieve and managesieve plug-in for dovecot LDA.
```

I also saw `dovecot-managesieved` but as I was **not** going to implement a client sieve functionality I did not install that.

Anyway I could not even get to first base with Sieve, Dovecot simply did not know about it. I went on IRC and chatted with Aki Tuomi who confirmed that "yeah, looks like there is some packaging mistake." because the directory `/usr/lib64/dovecot/settings` was empty. As a workaround he suggested "you need to install dovecot-managesieved as workaround". I did that and as a result the following files appeared:

```
-rwxr-xr-x 1 root root 15560 Jan  8 12:13 libmanagesieve_login_settings.so
-rwxr-xr-x 1 root root 15840 Jan  8 12:13 libmanagesieve_settings.so
-rwxr-xr-x 1 root root 19656 Jan  8 12:13 libpigeonhole_settings.so
```

The `dovecot -n` errors went away, it recognised the sieve directives, and I continued with the Sieve setup. All — `dovecot.conf`, sieve files source and compiled — installed OK. But the sieve functionality simply refused to work. I got advice and we found the following which essentially points to sieve (even with `dovecot-managesieved` installed) not working. After installing everything — dovecot.conf, sieve files (compiled successfully) and a pipe to a shell script to call `rspamc` nothing seemed to happen.

* `journalctl -f -u dovecot | grep -E "sieve|pipe"` -> nothing showed
* `rspamc stat` -> 'Messages scanned' & 'Messages learned' no increase

When we checked we found the following:

1) `lib90_sieve_settings.so` (which should be in `/etc/lib64/dovecot/settings`) is missing from the system.

  `find / -name "lib90_sieve_settings.so"` -> not found

I believe the file is critical for the running of (Dovecot using) Sieve?

2) The Dovecot build options missing any sieve functionality:

```
#dovecot --build-options
Build options: ioloop=epoll notify=inotify openssl io_block_size=8192
SQL driver plugins: mysql postgresql sqlite
Passdb: ldap pam passwd passwd-file sql
Userdb: ldap(plugin) passwd prefetch passwd-file sql
```

I believe (I was told) that minus the above (even though `dovecot-managesieved` was installed as well as `dovecot-sieve`) Sieve simply will not function.

Is this a bug/packaging error?

Regards

Patrick


ENVIRONMENT:
============

Software
--------
* Rocky Linux 9.7 (RHEL)
* Postfix 3.10 Built from source
* Postscreen running in Postfix
* Dovecot 2.4 installed from Dovecot repo
* Valkey 9.0.3 (Redis replacement)
* Rspamd 3.14.3

Setup
-----
* Rspamd <-> Valkey communicate via Unix socket
* Postfix & Dovecot <-> Rspamd via inet port/milter: 
    smtpd_milters = inet:localhost:11332
    non_smtpd_milters = inet:localhost:11332
* 'First line defence' = DNSBL via postscreen
* Rspamd SPF checking, DKIM signing and DMARC configured

All of the above installed, working and tested.


DOVECOT PACKAGES INSTALLED:
===========================

```
Name         : dovecot
Version      : 2.4.2
Architecture : x86_64
Source       : dovecot-2.4.2-2.src.rpm
>From repo    : dovecot-2.4-latest

Name         : dovecot-sieve
Version      : 2.4.2
Architecture : x86_64
Source       : dovecot-sieve-2.4.2-2.src.rpm
>From repo    : dovecot-2.4-latest

Name         : dovecot-managesieved		(see note about this in the email)
Version      : 2.4.2
Architecture : x86_64
Source       : dovecot-sieve-2.4.2-2.src.rpm
>From repo    : dovecot-2.4-latest

Name         : dovecot-submissiond
Version      : 2.4.2
Architecture : x86_64
Source       : dovecot-2.4.2-2.src.rpm
>From repo    : dovecot-2.4-latest

Name         : dovecot-imapd
Version      : 2.4.2
Architecture : x86_64
Source       : dovecot-2.4.2-2.src.rpm
>From repo    : dovecot-2.4-latest

Name         : dovecot-lmtpd
Version      : 2.4.2
Architecture : x86_64
Source       : dovecot-2.4.2-2.src.rpm
>From repo    : dovecot-2.4-latest

Name         : dovecot-lua
Version      : 2.4.2
Architecture : x86_64
Source       : dovecot-2.4.2-2.src.rpm
>From repo    : dovecot-2.4-latest
```


OUTPUT OF `dovecot -n`:
=======================

```
# dovecot -n
# 2.4.2-2 (0962ed2104): /etc/dovecot/dovecot.conf
# Pigeonhole version 2.4.2-2 (767418c3)
# OS: Linux 5.14.0-611.34.1.el9_7.x86_64 x86_64 Rocky Linux release 9.7 (Blue Onyx)
# Hostname: srv01.example.com
dovecot_config_version = 2.4.2
auth_default_domain = example.com
auth_mechanisms = plain
auth_username_format = %{user | lower }
dovecot_storage_version = 2.4.2
mail_access_groups = vmail
mail_control_path = ~/control
mail_driver = maildir
mail_gid = 5000
mail_home = /var/vmail/%{user | domain }/%{user | username }
mail_index_path = ~/indexes
mail_path = %{home}/Maildir
mail_privileged_group = vmail
mail_uid = 5000
mailbox_list_utf8 = yes
protocols = imap lmtp
sieve_global_extensions {
  vnd.dovecot.pipe = yes
}
sieve_pipe_bin_dir = /etc/dovecot/sieve/bin
sieve_plugins {
  sieve_imapsieve = yes
  sieve_extprograms = yes
}
sieve_trace_dir = /var/log/dovecot/sieve-trace
sieve_trace_level = actions
ssl = required
syslog_facility = local5
protocol lmtp {
  mail_plugins {
    sieve = yes
  }
}
ssl_server {
  cert_file = /etc/ssl/server/server_example_com.crt
  key_file = /etc/ssl/server/server_example_com.key
}
passdb passwd-file {
  auth_username_format = %{user | username}
  default_password_scheme = SHA512-CRYPT
  passwd_file_path = /etc/dovecot/passwd
}
userdb passwd-file {
  auth_username_format = %{user | username}
  passwd_file_path = /etc/dovecot/passwd
  fields {
    gid:default = 5000
    uid:default = 5000
  }
}
service lmtp {
  unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postfix
    mode = 0600
    user = postfix
  }
}
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0660
    user = postfix
  }
}
service imap-login {
  inet_listener imap {
    port = 0
  }
  inet_listener imaps {
    port = 993
    ssl = yes
  }
}
service auth-worker {
  user = $SET:default_internal_user
}
service anvil {
  unix_listener anvil {
    group = $SET:default_internal_group
    mode = 0660
  }
}
service doveadm {
  unix_listener doveadm-server {
    mode = 0600
    user = $SET:default_internal_user
  }
}
sieve_script rspamd_to_junk {
  driver = file
  path = /etc/dovecot/sieve/rspamd-to-junk.sieve
  type = before
}
namespace inbox {
  mail_plugins {
    imap_sieve = yes
  }
  inbox = yes
  mailbox Junk {
    auto = create
    autoexpunge = 90d
    special_use = "\\Junk"
    sieve_script report-spam {
      cause = copy
      path = /etc/dovecot/sieve/report-spam.sieve
      type = before
    }
  }
  imapsieve_from Junk {
    sieve_script report-ham {
      cause = copy
      path = /etc/dovecot/sieve/report-ham.sieve
      type = before
    }
  }
  mailbox Drafts {
    auto = subscribe
    special_use = "\\Drafts"
  }
  mailbox Sent {
    auto = subscribe
    special_use = "\\Sent"
  }
  mailbox Trash {
    auto = subscribe
    special_use = "\\Trash"
  }
}
```
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