[Pkg-matrix-maintainers] Bug#1087239: matrix-synapse: Does not work with current python3-twisted (24.10)

[Adam Lackorzynski]

Package: matrix-synapse
Version: 1.116.0-3+b1
Severity: grave
Justification: renders package unusable

Hi,

with the update of python3-twisted in unstable to 24.10.0-1,
matrix-synapse refuses to start:

$ /usr/bin/python3 -m synapse.app.homeserver --config-path=/etc/matrix-synapse/homeserver.yaml --config-path=/etc/matrix-
Traceback (most recent call last):
  File "<frozen runpy>", line 189, in _run_module_as_main
  File "<frozen runpy>", line 112, in _get_module_details
  File "/usr/lib/python3/dist-packages/synapse/app/__init__.py", line 30, in <module>
    check_dependencies.check_requirements()
  File "/usr/lib/python3/dist-packages/synapse/util/check_dependencies.py", line 210, in check_requirements
    m = import_module(n)
        ^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/ldap_auth_provider.py", line 25, in <module>
    from synapse.module_api import ModuleApi
  File "/usr/lib/python3/dist-packages/synapse/module_api/__init__.py", line 58, in <module>
    from synapse.handlers.account_data import ON_ACCOUNT_DATA_UPDATED_CALLBACK
  File "/usr/lib/python3/dist-packages/synapse/handlers/account_data.py", line 27, in <module>
    from synapse.replication.http.account_data import (
  File "/usr/lib/python3/dist-packages/synapse/replication/http/__init__.py", line 24, in <module>
    from synapse.replication.http import (
  File "/usr/lib/python3/dist-packages/synapse/replication/http/account_data.py", line 28, in <module>
    from synapse.replication.http._base import ReplicationEndpoint
  File "/usr/lib/python3/dist-packages/synapse/replication/http/_base.py", line 38, in <module>
    from synapse.http.site import SynapseRequest
  File "/usr/lib/python3/dist-packages/synapse/http/site.py", line 39, in <module>
    from synapse.http.proxy import ProxySite
  File "/usr/lib/python3/dist-packages/synapse/http/proxy.py", line 72, in <module>
    _canonicalHeaderName = Headers()._encodeName
                           ^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'Headers' object has no attribute '_encodeName'

Downgrading python3-twisted to the previous version 24.7.0-3 makes it work again.

matrix-synapse upstream has modified synapse/http/proxy.py, changing
those lines, however, this just happened last week. So eventually this
should be gone with the next update of matrix-synapse.


-- System Information:
Debian Release: trixie/sid
  APT prefers unstable
Architecture: amd64 (x86_64)

ii  python3-twisted            24.10.0-1