Using the :match attribute for custom matching for a Helm source

Question

I'm trying to create a Helm source which matches the basename of files. I created a source which splits the basename of files in recentf list and puts the path behind it in parens (it uses the (DISPLAY . REAL) candidate format, so the real item is still available for opening the file.

I then added a :match attribute function which should match only the basename of the file when searching, but for some reason it still matches the path part.

Can someone tell me why?

(helm
 :sources
 (list
  (helm-build-sync-source
      "Recent Files Basenames"
    :candidates
    (lambda ()
      (mapcar (lambda (f)
                (cons (format
                       "%s (%s)"
                       (file-name-nondirectory f) f) f))
              recentf-list))

    :match (lambda (candidate)
             (string-match
              helm-pattern
              (substring candidate 0
                         (string-match "(" candidate))))

    :action '(("Find File" . find-file)))))

Answer 1

You're missing :multimatch nil. You can also replace the match slot with:

:match-strict (lambda (candidate)
                (string-match helm-pattern
                              (helm-basename candidate)))

or

:match-part (lambda (candidate)
              (helm-basename candidate))