embark-target-guess-file-at-point does not play nicely with thing-at-point-provider-alist

[9viz]

Hi,

In transmission-files-mode (from transmission.el), I register a filename provider like below:

(defun vz/transmission-files-register-tap-provider ()
  (setq-local thing-at-point-provider-alist
	  (cons `(filename . ,#'transmission-files-file-at-point)
		thing-at-point-provider-alist)))

(add-hook 'transmission-files-mode-hook #'vz/transmission-files-register-tap-provider)

where if I have the point anywhere on a line such as

100% normal    yes    1.8GiB All.My.Friends.Hate.Me.2021.1080p.WEBRip.x264-RARBG.mp4

then embark-act does not pick the filename provided by thing-at-point-provider-alist. This can be confirmed by manually evaulating

(thing-at-point 'filename)

or

(thing-at-point 'existing-filename)

This seems to be because embark-target-guess-file-at-point calls bounds-of-thing-at-point which fails because there is no way to provide a bound here (bounds-of-thing-at-point-provider-alist is a thing from Emacs 30.1). Moreover, even if there was a bounds function, it would surely fail because of the consequent ffap-file-at-point which would return nil.

Is there a way to account for this deficiency other than writing a new target finding function?