TmuxPaneCurrentCommand -> TmuxNavigatorProcessList

Previously we used the `{pane_current_command}` tmux variable and
matched against that, but a while back we switched to using the process
list to better handle some edge cases.

Overall that change has been a win, but the documentation has lagged a
bit around the debugging command `:TmuxPaneCurrentCommand` which is no
longer relevant.

This change replaces `:TmuxPaneCurrentCommand` with a new
`:TmuxNavigatorProcessList` which should allow us to debug the actual
issue related to the `ps` command.

Author: christoomey

README.md

@@ -116,7 +116,10 @@ Left would be created with `nnoremap <silent> <c-h> :TmuxNavigateLeft<cr>`.
 
 ##### Autosave on leave
 
-You can configure the plugin to write the current buffer, or all buffers, when navigating from Vim to tmux. This functionality is exposed via the `g:tmux_navigator_save_on_switch` variable, which can have either of the following values:
+You can configure the plugin to write the current buffer, or all buffers, when
+navigating from Vim to tmux. This functionality is exposed via the
+`g:tmux_navigator_save_on_switch` variable, which can have either of the
+following values:
 
 Value  | Behavior
 ------ | ------
@@ -211,10 +214,17 @@ altered to avoid conflicting with the mappings from the plugin.
 
 Another option is that the pattern matching included in the `.tmux.conf` is
 not recognizing that Vim is active. To check that tmux is properly recognizing
-Vim, use the provided Vim command `:TmuxPaneCurrentCommand`. The output of
-that command should be a string like 'vim', 'Vim', 'vimdiff', etc. If you
-encounter a different output please [open an issue][] with as much info about
-your OS, Vim version, and tmux version as possible.
+Vim, use the provided Vim command `:TmuxNavigatorProcessList`. The output of
+that command should be a list like:
+
+```
+Ss   -zsh
+S+   vim
+S+   tmux
+```
+
+If you encounter a different output please [open an issue][] with as much info
+about your OS, Vim version, and tmux version as possible.
 
 [open an issue]: https://github.com/christoomey/vim-tmux-navigator/issues/new
 

plugin/tmux_navigator.vim

@@ -64,10 +64,10 @@ function! s:TmuxCommand(args)
   return system(cmd)
 endfunction
 
-function! s:TmuxPaneCurrentCommand()
-  echo s:TmuxCommand("display-message -p '#{pane_current_command}'")
+function! s:TmuxNavigatorProcessList()
+  echo s:TmuxCommand("run-shell 'ps -o state= -o comm= -t ''''#{pane_tty}'''''")
 endfunction
-command! TmuxPaneCurrentCommand call s:TmuxPaneCurrentCommand()
+command! TmuxNavigatorProcessList call s:TmuxNavigatorProcessList()
 
 let s:tmux_is_last_pane = 0
 augroup tmux_navigator