Getting "file reference 'mainExecutableFile' not defined"

[stretchkennedy]

In #8 an optional flag --run-after/-r flag was added. This adds a CustomAction that is always added, even if runAfter isn't set:

      el('CustomAction', {
	    Id: "LaunchInstalledExe",
	    FileKey: "mainExecutableFile", // what goes here?
	    ExeCommand: "",                // and here?
	    Execute: "immediate",
	    Impersonate: "yes",
	    Return: "asyncNoWait"
      }),

The line FileKey: "mainExecutableFile" causes the following error for me (on Win 10):

<redacted>/node_modules/msi-packager/cli.js:80
  if (err) throw err
           ^

Error: Command failed: wixl /tmp/msi-packager202137-26063-1f0w89q.iyx7 -o <redacted>/release/setup.msi

(wixl:26074): GLib-GObject-WARNING **: 20:09:22.947: g_object_set_is_valid_property: object class 'WixlWixProperty' has no property named 'Secure'

(wixl:26074): wixl-ERROR **: 20:09:22.947: builder.vala:1076: file reference 'mainExecutableFile' not defined

    at ChildProcess.exithandler (child_process.js:308:12)
    at ChildProcess.emit (events.js:314:20)
    at maybeClose (internal/child_process.js:1022:16)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:287:5) {
  killed: false,
  code: null,
  signal: 'SIGTRAP',
  cmd: 'wixl /tmp/msi-packager202137-26063-1f0w89q.iyx7 -o <redacted>/setup.msi'
}

I believe this is happening because that block of code adds a FileReference to mainExecutableFile, which causes wixl to throw an error if that file doesn't exist.

I'm not really sure what the proper fix is here - I'm unable to get --run-after to run the installed executable, so I can't test. In a few minutes I'll put up a PR which doesn't defined LaunchInstalledExe unless runAfter is set, which should be a safe way to isolate these problems to --run-after. However, I'd appreciate some help debugging --run-after and checking whether the entire CustomAction can be removed, since there's another CustomAction defined above that seems to do the actual running of the executable and since the LaunchInstalledExe ID isn't used anywhere else.