Use b:term_title for terminal buffer display names.

[charlesg3]

Problem

When multiple terminal buffers are open, BufExplorer displays each one as !PID:shell (e.g. !22290:zsh). With several terminals running it is difficult to tell them apart — the PID is meaningless at a glance.

Solution

Neovim stores the OSC 0/2 title emitted by the terminal program in the buffer-local variable b:term_title. When a shell has preexec/precmd hooks that set the title to the running command or current directory, this variable contains something much more useful than the PID.

This change checks b:term_title after the existing !PID:shell name is constructed, and substitutes it when a meaningful title is present:

let term_title = getbufvar(buf.bufNbr, 'term_title', '')
if !empty(term_title) && term_title !~# '^term://'
    let name = '!' . term_title
endif

The ^term:// guard is necessary because Neovim initialises b:term_title to the raw terminal URI (e.g. term://~//22290:/bin/zsh) before any OSC sequence has arrived. Without it, that default value would be used verbatim.

Result

With a shell configured to emit OSC titles (e.g. zsh preexec/precmd hooks), terminals appear in the buffer list as:

 3  a   !nvim init.vim
 4  a   !~/src/myproject
 5  a   !sleep 100

instead of:

 3  a   !22290:zsh
 4  a   !22291:zsh
 5  a   !22292:zsh

Falls back gracefully to the existing !PID:shell format when b:term_title has not been set by the terminal.

[drmikehenry]

This looks like a useful extension. I don't use the :terminal feature myself, but I tried out this change. On my system, b:term_title has the form username@hostname CUR_DIR regardless of what's running in the terminal. I'm sure I could adjust things to make b:term_title more useful, and I would expect to do so if/when I start using :terminal more. But without such adjustment, terminals now end up looking much the same in BufExplorer, at least if the current working directory is the same. For example, after cd / and nvim, if I launch :terminal window and create a pair of :terminal windows, BufExplorer shows:

  2 %aR   !mike@f16: / / line 1
  1 #aR   !mike@f16: / / line 1

There's not much (other than the buffer number) to distinguish these terminals on my system.

If I then cd /usr/local/lib in one, BufExplorer now shows:

  2 %aR   !mike@f16: lib /usr/local/lib line 2
  1 #aR   !mike@f16: /   /              line 1

It's a bit redundant having the directory name duplicated by the path column.

The PID distinguisher is lost here; but a user would likely rather remember the the (probably shorter) buffer number instead of the PID anyway, if the s:term_title doesn't have better information in it. But if the PID seems desirable to display, it could be retained by moving the new logic above the if pid < 0 line and setting shellName instead of name, e.g.:

        let term_title = getbufvar(buf.bufNbr, 'term_title', '')
        if !empty(term_title) && term_title !~# '^term://'
            let shellName = term_title
        endif

        if pid < 0

With BufExplorer showing:

  2 %aR   !321637:mike@f16: / / line 1
  1 #aR   !321625:mike@f16: / / line 1

However, this comes at the expense of quite a few columns in the display, and probably isn't that valuable. Users wanting a better display in BufExplorer would likely want to configure things so that b:term_title itself is more useful.

I also didn't test what happens if the currently running command is very long; that might push subsequent columns off the right side of the display. Perhaps if b:term_title is longer than some threshold, only a prefix should be retained.

In any event, I think this idea has merit. As a very infrequent user of :terminal, the pull request as-is won't hurt me at all (since I have no terminal windows open in general). Heavy users of :terminal would also likely be interested in setting up their systems so that b:term_title is more valuable. It would be useful to extend the BufExplorer documentation to show how to set things up on a typical system (ideally at least Linux and Windows) to set b:term_title in a better manner. It might make sense to allow BufExplorer users to configure how terminal names are displayed if there are multiple reasonable ways different users might prefer, though I don't have any feel for what would be most beneficial.

I expect @jlanzarotta will weigh in when he gets some time; I know he's frequently fairly swamped with other things.

[jlanzarotta]

I am currently stuck on Windows development, so I am pretty sure this is not reproduceable there... I do not use NeoVim either. As long as this change does not break Windows Vim, I will merge it. Let me take a look and I hope to merge in the next day or so.

[charlesg3]

Great -- thanks so much for taking a look and merging. It's definitely a QoL improvement on my end where many of my terminal apps set nice "titles" (and I have my shell do the same) so now I can easily differentiate what's running in each of the shells and not left guessing based on PID. 🙏