nixos/yabar: fix module & test (#46954)

The `pkgs.yabar` package is relatively old (2016-04) and contains
several issues fixed on master. `yabar-unstable` containsa recent master
build with several fixes and a lot of new features (I use
`yabar-unstable` for some time now and had no issues with it).

In the upstream bugtracker some bugs could be fixed on ArchLinux by
simply installing `yabar-git` (an AUR package which builds a recent
master).

To stabilize the module, the option `programs.yabar.package` now
defaults to `pkgs.yabar-unstable` and yields a warning with several
linked issues that are known on `pkgs.yabar`.

The test has been refactored as well to ensure that `yabar` actually
starts (and avoid non-deterministic random success) and takes a
screenshot of a very minimalistic configuration on IceWM.

Fixes #46899

1 files changed, 15 insertions, 2 deletions

diff --git a/nixos/modules/programs/yabar.nix b/nixos/modules/programs/yabar.nix
index a01083c3ace..db085211366 100644
--- a/nixos/modules/programs/yabar.nix
+++ b/nixos/modules/programs/yabar.nix
@@ -44,10 +44,23 @@ in
       enable = mkEnableOption "yabar";
 
       package = mkOption {
-        default = pkgs.yabar;
-        example = literalExample "pkgs.yabar-unstable";
+        default = pkgs.yabar-unstable;
+        example = literalExample "pkgs.yabar";
         type = types.package;
 
+        # `yabar-stable` segfaults under certain conditions.
+        apply = x: if x == pkgs.yabar-unstable then x else flip warn x ''
+          It's not recommended to use `yabar' with `programs.yabar', the (old) stable release
+          tends to segfault under certain circumstances:
+
+          * https://github.com/geommer/yabar/issues/86
+          * https://github.com/geommer/yabar/issues/68
+          * https://github.com/geommer/yabar/issues/143
+
+          Most of them don't occur on master anymore, until a new release is published, it's recommended
+          to use `yabar-unstable'.
+        '';
+
         description = ''
           The package which contains the `yabar` binary.