Tmux split window does NOT use current directory after installation of fish release 3

[CermakM]

Tmux split window does NOT use current directory after installation of fish release 3.

I tried setting the following from fish to bash, but the issue is the same. I don't know anything about the underlying connection of fish and tmux. However, this issue occured right after the installation of fish release 3.

set -g default-command /usr/bin/fish
set -g default-shell /usr/bin/fish

The relevant tmux config lines:

# Splitting to current directory instead of home dir
bind-key -r \ split-window -h -c "#{pane_current_path}"
bind-key -r - split-window -v -c "#{pane_current_path}"

Fish version

> fish --version
fish, version 3.0.2

Thanks for the help!

[faho]

There's no need to set both default-command and default-shell.

Doing so will end up running fish -c /usr/bin/fish, which is just wasteful.

Also it turns out that not doing it does not trigger the issue.

I'm not quite sure what's actually happening here, but that's a great workaround because it's what you should be doing in the first place.

[CermakM]

Right, gotcha.. Thank. This doesn't appear to have any impact on my site, however.
I did notice one thing, though. If I split the panes while having a running process in the terminal (i.e. vim), it actually splits into current directory.

[faho]

Okay, so, the way tmux reads the pwd for this is os-dependent and actually kind of weird.

On linux it boils down to readlink /proc/$pgroup/cwd. Where $pgroup is the pgroup in control of the terminal.

Which in case you're doing fish -c fish is the pid of the parent fish, because fish 3 stopped putting itself into a new pgroup in all cases.

If you use bash as default-shell, then that boils down to bash -c fish, only bash does an automatic exec in that case, so it appears to work.

If you run a command, that also works as fish puts it in its own pgroup in control of the terminal.

I'm unsure why in fish -c fish the outer fish doesn't do that to the inner one. I'm assuming it's to do with us basically not doing job control in non-interactive shells.

@mqudsi: Any ideas?

[CermakM]

Oh I see, you nailed it.. setting default-shell to bash and default-command to fish does the job. This is really fishy 😄

EDIT: I had to put both of these into .tmux.conf and source it in order for the changes to take place.

[faho]

setting default-shell to bash and default-command to fish does the job

@CermakM: Please try setting just default-shell to fish and leaving default-command undefined. That works for me, and seems like what you should do, normally.

[CermakM]

@faho, works now, after I've sourced the default-shell command .. now I can leave it out and the tmux still works as expected. Maybe uses some sort of cache / artifact mechanism? No idea.

[CermakM]

I did a clean reinstall to Fedora 30 and ran into the same issue once again. I managed to solve it by setting the default shell to be fish system-wise by running chsh -s /usr/bin/fish and completely removing the set -g default-shell /usr/bin/fish line from ~/.tmux.conf. Now it seems to work correctly.

[mrm1st3r]

I have the same issue after upgrading to Ubuntu 19.04, which upgraded fish to 3.0.2.
I use byobu as a tmux wrapper with it's default configuration.

I don't get the problem, if I'm running any application when splitting the window.

[mqudsi]

I'm unsure why in fish -c fish the outer fish doesn't do that to the inner one. I'm assuming it's to do with us basically not doing job control in non-interactive shells.

Yup. Which I tried changing in a local branch before the 3.0 release but that broke a few subtle things we don't have tests for (because our current test system doesn't make that easy). I don't know if there's a very small subset of actions we currently do in job control mode that we can safely do always, regardless of how fish is being invoked.

[fent]

I'm having the same issue. changing default-shell or default-command doesn't fix it :(

[evantravers]

I just started seeing something like this… it's really weird.

It happens even if I comment out my whole tmux.conf, but one thing I noticed is that if I'm currently running a command (like vim or less,) pane_current_path is set correctly… but if I'm in a blank fish shell, it doesn't work. Does that ring a bell for anyone?

I started to record an asciinema to demonstrate, but that weirded it out too. Here's a (too fast) screencast via gif…