A lot of open-source projects already migrated to gitlab: all
FreeDesktop projects, all Gnome projects; and KDE are likely to migrate
soon too². Gnome reports: "After switching to GitLab, I noticed almost
immediately an increase in contributions from people I hadn’t met
before. I think GitLab really lowered the threshold for people getting
started"³.
I agree. I contribute often on github/gitlab, and the process is very simple. In comparison, Emacs has hurdles that requires much more motivation and persistance in order to contribute.
I think it boils down to this: on github/gitlab, almost everything is handled by git itself: you propose/test changes by creating/pulling branches on the repository/fork... so you basically only need to use git and click a few buttons in the browser (or use magithub/emacs-gitlab etc). With the Emacs model, you need to go back & forth between emails and git, copying patches, applying them, keeping track of where each changes is, etc. The extra step does not look like much but it is a lot, especially for simple changes.
4. Impossible to lose "merge request". I've seen in Emacs docs an
advice to send patch series to a bugtracker, because on emacs-devel
they can easily be forgotten. That can't happen so easily with gitlab,
where you have a tab with open merge requests.
Yeah, the maintainer job is easier, no need to remember which topics are the active ones. Searching for existing or past similar issues also feels simpler, but I guess that is just habit.
5. Discussion on patch series is easier to read. On mailing lists can
quickly appear a dozen of no longer relevant review mails, that refer
to something that was addressed. In Gitlab the addressed comments can
be marked as such, and get collapsed.
It's also easier to view the current states of the commits, you don't need to search for the latest patch in the list of emails.
Now, the Emacs model is similar to the linux kernel dev & the git dev workflow, so obviously "it works fine" and has advantages too, but personally I think those are outweighted by the the disadvantages (or rather than the contribution experience is much nicer with gitlab).
Kind regards,
Philippe