topic: fix some API to make it more robust
The new code can deal with changes in upstream mercurial.
--HG-- branch : stable
This instance will be upgraded to Heptapod 1.3.3 (GitLab 16.9.6) on 2023-04-25 at 18:00 UTC+2
The new code can deal with changes in upstream mercurial.
--HG-- branch : stable