xmonad-testing VS xmonad-dbus

All is well and works properly. Now, however, I would like to switch to the git version of Xmonad by using xmonad-testing. For that I cloned the repo, switched both xmonad & xmonad-contrib branches to master and compiled executable. First of all, if I run the executable with `--version`, I get '0.15', that seems to me not correct. Shouldn't it be 0.16, even though it is not released yet? Second, I am not sure whether I need to somehow install the Git versions as libraries to be able to use new features and to get Vim with haskell-language-server recognize the new features. My configuration is in `~/.xmonad`. I think if I copy the config to the directory where the cloned repos are, it (using the new features) will work...

If don't build via the first method and you want to use a project-like structure as in xmonad-testing then yes, you need a cabal file. There is an example file available in the repo.

Depending on whether you want to use stack or cabal, there is xmonad-testing, which is a repository that solely exists to show users how to do this! Under build-scripts you can find examples for both stack and cabal (be sure to read the readme for how to use these). If you want to use cabal 3.4 then mind geekosaur's pr for things to work smoothly with the new- style commands which are now the default.

There are some example build scripts that I use that make it super easy.

I followed the instructions on this post, which sets ~/.xmonad as a stack project. I set xmonad-log (also tried with haskell-dbus) in the stack.yml as an extra-dep However, it is not working for me.

As an aside, you should use the bar you're most comfortable with. Sure most people use xmobar, but the point of xmonad is that you can create your favourite computing environment :) If you prefer polybar then it's not terribly hard to get it to work with xmonad. You can either send what you want down a pipe and let polybar read from that pipe or you can use something like xmonad-dbus to let them talk via dbus.