[Feature request]: `hide-empty` option for `niri/workspaces` module

[og900aero]

Environment

• Waybar 0.15.x
• niri compositor

Background

niri always maintains at least one extra empty workspace beyond the last used one (this is intentional niri behavior by design). As a result, the niri/workspaces module always renders at least one button with the button.empty class.

Problem

There is currently no way to hide empty workspaces in the niri/workspaces module. Attempting to hide them via CSS (opacity: 0, min-width: 0, padding: 0, etc.) does not fully work because the GTK Box container still preserves spacing between child elements, leaving a visible gap in the bar.

Requested change

Add a hide-empty boolean option (default: false) to the niri/workspaces module that completely removes empty workspace buttons from the widget tree, rather than just styling them.

Example config

"niri/workspaces": {
  "format": "{name}",
  "hide-empty": true
}

Workaround

Currently the only reliable workaround is a custom polling script that filters out empty workspaces and outputs Pango markup as a single custom/ module. This works visually but loses per-workspace click support, which is only available in the native module.
Like that:

#!/bin/bash

niri msg --json workspaces | jq -c '
  sort_by(.idx) | 
  map(select(.is_focused or (.active_window_id != null))) | 
  {
    text: (map(
      if .is_focused then 
        "<span background=\"#dc312e\" color=\"#ffffff\"> \(.name) </span>" 
      else 
        "<span color=\"#dddddd\"> \(.name) </span>" 
      end
    ) | join("")),
    class: "niri-workspaces"
  }
```'

[cebem1nt]

Done! It will be available in the next release

[og900aero]

Done! It will be available in the next release

Thank u so much!