This is about as precise as I'm able to formulate it.. After installing tmux-3.6 I found that it threw an "open terminal failed: not a terminal" error on servers that have active tmux jobs running, which were started from the previous version of tmux (tmux-3.5a_1). Reinstalling the previous version solved the issue. This was reproducible on a body of 100+ FreeBSD (14.3) installs. No runnning tmux jobs: tmux-3.6 worked just fine. Already running tmux jobs: tmux-3.6 throws an error and only reinstalling a previous version helped. This goes for installs within the same package build in Poudriere where everything is virtually identical -> tmux jobs already running or not was really the only determining factor.
We are probably looking at an issue with a pre-existing /tmp/tmux-0/default ?
https://github.com/tmux/tmux/issues/4699
Thanks for the update, and since I'm using the word: why isn't this marked in /usr/ports/UPDATING ?
Also, "Note that it is very important to restart tmux entirely after upgrading." After upgrading, running tmux sessions cannot be accessed or attached in any way, which is quite problematic. There is no way to restart tmux (afaik), so you have to basically kill the pid of the running tmux server (losing active tmux sessions) of of the individual sessions (same effect). Or have all sessions open while upgrading tmux in another session. But then you have to kill the pane anyway .. So is there actually any way to perform the upgrade without killing the sessions (before or after, from the outside or from within)?
A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/ports/commit/?id=458a737a70fdcd2882396967fcd19d2632400847 commit 458a737a70fdcd2882396967fcd19d2632400847 Author: Joseph Mingrone <jrm@FreeBSD.org> AuthorDate: 2025-12-01 18:55:45 +0000 Commit: Joseph Mingrone <jrm@FreeBSD.org> CommitDate: 2025-12-01 19:07:36 +0000 sysutils/tmux: Document requirement to restart tmux after upgrading PR: 291325 Reported by: freebsd@bengrimm.net Sponsored by: The FreeBSD Foundation UPDATING | 11 +++++++++++ sysutils/tmux/Makefile | 1 + sysutils/tmux/pkg-message (new) | 13 +++++++++++++ 3 files changed, 25 insertions(+)
I added pkg-message so that after every tmux package upgrade, users will be reminded to restart tmux. I also added an entry to /usr/ports/UPDATING, as it's particularly important for the 3.6 upgrade, as described in the GitHub issue Herbert shared. Someone asked a similar question to yours about restarting tmux: https://github.com/tmux/tmux/issues/4699#issuecomment-3592401112. @nicm responded, confirming that `pkill tmux` may be necessary. Please let me know if this should be reopened.
For 'posterity', `tmux kill-server` works just fine for that.