centaur-tabs-build-helm-source "fix"

M-x centaur-tabs-build-helm-source shows the following error message:

centaur-tabs-build-helm-source: Invalid function: helm-build-sync-source

System info

Centaur-tabs:

• ;; Version: 5
• centaur-tabs-20200821.335/

GNU Emacs 27.1 (build 1, x86_64-w64-mingw32) of 2020-08-21 Windows 10 2004

Setup

It was tested with the centaur-tabs and helm packages installed, and these lines added to the init.el

(require 'centaur-tabs)
(centaur-tabs-mode t)
(global-set-key (kbd "C-<prior>")  'centaur-tabs-backward)
(global-set-key (kbd "C-<next>") 'centaur-tabs-forward)

(require 'helm)

A possible solution

I searched for the invalid function name in Spacemacs and found that it's used in the julia layer: https://github.com/syl20bnr/spacemacs/blob/3d5d4b2f280259daa737e8e3558eb6b61ae4ad54/layers/%2Blang/julia/funcs.el#L54

like this:

(helm :sources (helm-build-sync-source "test"
                     :candidates (spacemacs//julia-hash-to-alist julia-latexsubs)
                     :fuzzy-match t
                     :action (lambda (candidate) (insert candidate)))
          :buffer "*helm julia latex insert*")

When (helm :sources is added to the centaur-tabs-build-helm-source function.

Before:

https://github.com/ema2159/centaur-tabs/blob/5453317b6b9f68bfbd934eee3b883207bfa331e0/centaur-tabs-interactive.el#L302-L310

After:

  (defun centaur-tabs-build-helm-source ()
    "Display a list of current buffer groups in Helm."
    (interactive)
    (setq helm-source-centaur-tabs-group
          (when (featurep 'helm)
            (require 'helm)
            (helm :sources (helm-build-sync-source "Centaur-Tabs Group"
                             :candidates #'centaur-tabs-get-groups
                             :action '(("Switch to group" . centaur-tabs-switch-group)))))))

Then it seems to work as expected.

Issue:

The group choice(s) are not shown when there are two windows:

It's a refresh issue, when the helm buffer doesn't open correctly.

The list of candidates appear when:

• The cursor is moved: C-n or C-p
• A character is typed.

@duianto Did you solve this issue for yourself? Is this something in centaur tabs that needs to be solved?

This issue occurs in centaur-tabs.

After installing centaur-tabs and helm from melpa.

Before

Calling: M-x centaur-tabs-build-helm-source shows:

centaur-tabs-build-helm-source: Invalid function: helm-build-sync-source

A possible solution

The fix seems to be to wrap (helm :sources ... ) around the expression: (helm-build-sync-source "Centaur-Tabs Group" ... in the function: https://github.com/ema2159/centaur-tabs/blob/cde3469d77f83b0877f2a7c727ca101cfeb86401/centaur-tabs-interactive.el#L303-L311

The emacs-helm wiki has some usage examples here: https://github.com/emacs-helm/helm/wiki/Developing#creating-a-source

With (helm :sources ... ) added.

After

M-x centaur-tabs-build-helm-source opens the expected *helm* buffer:

System info

centaur-tabs-20220112.1239 helm-20220211.1707 GNU Emacs 27.2 (build 1, x86_64-w64-mingw32) of 2021-03-26 Windows 21H2