home/tmux/default.nix

@@ -11,19 +11,6 @@ in
     enable = my.mkDisableOption "tmux terminal multiplexer";
 
     enablePassthrough = mkEnableOption "tmux DCS passthrough sequence";
-
-    trueColorTerminals = mkOption {
-      type = with types; listOf str;
-      default = lib.my.nullableToList config.my.home.terminal.program;
-      defaultText = ''
-        `[ config.my.home.terminal.program ]` if it is non-null, otherwise an
-        empty list.
-      '';
-      example = [ "xterm-256color" ];
-      description = ''
-        $TERM values which should be considered to always support 24-bit color.
-      '';
-    };
   };
 
   config.programs.tmux = lib.mkIf cfg.enable {
@@ -88,14 +75,6 @@ in
           set -g allow-passthrough on
         ''
       }
-
-      # Force 24-bit color for each relevant $TERM
-      ${
-        let
-          mkTcFlag = term: ''set -as terminal-features ",${term}:RGB"'';
-        in
-        lib.concatMapStringsSep "\n" mkTcFlag cfg.trueColorTerminals
-      }
     '';
   };
 }

hosts/homes/ambroisie@mousqueton/default.nix

@@ -20,6 +20,8 @@
   # I use scripts that use the passthrough sequence often on this host
   my.home.tmux.enablePassthrough = true;
 
-  # HTerm uses `xterm-256color` as its `$TERM`, so use that here
-  my.home.tmux.trueColorTerminals = [ "xterm-256color" ];
+  programs.tmux.extraConfig = ''
+    # Setup 24-bit color explicitly, as the default terminfo entry does not
+    set-option -sa terminal-overrides ",xterm-256color:Tc"
+  '';
 }

lib/lists.nix

@@ -24,10 +24,4 @@ in
   #   (any -> value)
   #   [ any ]
   mapFilter = pred: f: attrs: filter pred (map f attrs);
-
-  # Transform a nullable value into a list of zero/one element.
-  #
-  # nullableToList ::
-  #   (nullable a) -> [ a ]
-  nullableToList = x: if x != null then [ x ] else [ ];
 }