writeTextFile: revert workaround for executable = null

nixos/doc/manual/release-notes/rl-2311.section.md

@@ -14,6 +14,8 @@
 
 ## Backward Incompatibilities {#sec-release-23.11-incompatibilities}
 
+- `writeTextFile` now requires `executable` to be boolean, values like `null` or `""` will now fail to evaluate.
+
 - The latest version of `clonehero` now stores custom content in `~/.clonehero`. See the [migration instructions](https://clonehero.net/2022/11/29/v23-to-v1-migration-instructions.html). Typically, these content files would exist along side the binary, but the previous build used a wrapper script that would store them in `~/.config/unity3d/srylain Inc_/Clone Hero`.
 
 - `etcd` has been updated to 3.5, you will want to read the [3.3 to 3.4](https://etcd.io/docs/v3.5/upgrades/upgrade_3_4/) and [3.4 to 3.5](https://etcd.io/docs/v3.5/upgrades/upgrade_3_5/) upgrade guides

pkgs/build-support/trivial-builders/default.nix

@@ -141,7 +141,7 @@ rec {
     runCommand name
       { inherit text executable checkPhase allowSubstitutes preferLocalBuild;
         passAsFile = [ "text" ];
-        meta = lib.optionalAttrs (toString executable != "" && matches != null) {
+        meta = lib.optionalAttrs (executable && matches != null) {
           mainProgram = lib.head matches;
         } // meta;
       }