Package: ejabberd
Version: 24.12-3+deb13u2
Severity: normal
Dear Maintainer,
mod_matrix_gw (the experimental Matrix federation gateway) is non-functional
in the Trixie package because ejabberd 24.12 is built against Erlang/OTP 27,
whose *native* `json` module cannot encode the EEP-18 / jiffy-style
`{[{Key,Value},...]}` terms that ejabberd's `misc:json_encode_with_kv_lists/1`
passes to it. Every outbound Matrix event therefore crashes and nothing
federates.
Reproduce:
1. Enable mod_matrix_gw with an ejabberd_http listener on 8448 (/_matrix)
and an ed25519 signing key.
2. From a local XMPP account, send a chat to `user%remote.tld@matrix.<vhost>`.
3. Crash:
@mod_matrix_gw_room:handle_event/4:583 failed add_event: {error,
{unsupported_type, {[{<<"auth_events">>,[]}, {<<"content">>, ...},
... {<<"type">>,<<"m.room.message">>}]}},
[{json,do_encode,2,[{file,"json.erl"},{line,201}]},
{misc,json_encode_with_kv_lists,1,[{file,"misc.erl"},{line,143}]},
{mod_matrix_gw,content_hash,1,[{file,"mod_matrix_gw.erl"},{line,663}]},
{mod_matrix_gw_room,add_event,2,...},
{mod_matrix_gw_room,handle_event,4,...}]}
Confirmed it is the ejabberd+OTP-27 combination, not ejabberd itself:
building/running the same ejabberd config under Erlang/OTP 26 (ProcessOne's
`ejabberd/ecs` container, which bundles OTP 26) works correctly -- an
XMPP->Matrix direct message was delivered end-to-end. On OTP < 27 ejabberd
uses an external JSON library and is unaffected.
Upstream reports:
- https://github.com/processone/ejabberd/issues/4602 (this issue, with full
analysis, filed as a follow-up)
- https://github.com/processone/ejabberd/issues/4244 (closed; same root cause,
fix appears incomplete for OTP 27 -- also reproduced on 24.12 at
mod_matrix_gw:sign_json/2, mod_matrix_gw.erl:722)
Possible resolutions for the Debian package:
- Backport the upstream fix that makes `misc:json_encode_with_kv_lists/1`
OTP-27-safe (convert wrapped-proplists to maps / use a json encoder
callback), once available; or
- Document the limitation for the OTP-27 build.
Non-Matrix functionality is unaffected.
-- System Information:
Debian Release: 13 (trixie)
Architecture: amd64
Kernel: Linux 6.12.88+deb13-cloud-amd64
Locale: LANG=en_US.UTF-8
Versions of packages ejabberd depends on:
ii erlang-base 1:27.3.4.1+dfsg-1+deb13u2
