Helm + neotree on spacemacs: unable to use Tab to switch to selected directory

[phoe]

Expected behavior

When using neotree in spacemacs, I used to be able to use Tab to navigate to folders inside helm. Now that functionality is broken.

Actual behavior (from emacs-helm.sh if possible, see note at the bottom)

Error: split-window: Cannot split side window or parent of side window

Steps to reproduce (recipe)

Download current spacemacs
SPC f t to open neotree
Select a directory
Hit Tab

Backtraces if any (M-x toggle-debug-on-error)

I cannot copypaste the contents of *Backtrace* buffer because I cannot select text from it while the lower window is open, and once I close that window, the contents of that window disappear. The best I can give is a screenshot of my Emacs showing the backtrace.

Describe versions of Helm, Emacs, operating system, etc.

Spacemacs 0.200 stable

Are you using emacs-helm.sh to reproduce this bug (yes/no):

no

Other things

Discussed on the spacemacs issue tracker: syl20bnr/spacemacs#11368

[thierryvolpiatto]

Please report bugs starting from emacs-helm.sh, and not spacemacs.
Thanks.

[phoe]

I have run emacs with emacs-helm.sh but neotree is now not loaded.
The package is downloaded at ~/.emacs.d/elpa/neotree-20180616.1603
What steps are required to load neotree in this case?

[phoe]

I just noticed that the Tab button works just fine unless neotree is open. After I open and then close it, tab button works normally.

[thierryvolpiatto]

Michał Herda <notifications@github.com> writes:

I have run emacs with emacs-helm.sh but neotree is now not loaded. The package is downloaded at ~/.emacs.d/elpa/neotree-20180616.1603 What steps are required to load neotree in this case?

(load-file "/path/to/neotree.el") M-x neotree

…

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-- Thierry

[thierryvolpiatto]

I guess this bug is same as #2115, this because you or spacemacs, I don't know set (setq helm-default-display-buffer-functions '(display-buffer-in-side-window)) (just a guess).
So when you do this you have just what is expected, see documentation of display-buffer-in-side-window.
IOW there is no bug on the helm side for this.

[sdwolfz]

Thanks for pointing that out @thierryvolpiatto, we do have something like that: https://github.com/syl20bnr/spacemacs/blob/c7a103a772d808101d7635ec10f292ab9202d9ee/layers/%2Bspacemacs/spacemacs-completion/funcs.el#L108.

I'll take a look at what that code does and see if I can come up with a solution.

[phoe]

@thierryvolpiatto It's weird - when I run spacemacs, helm-default-display-buffer-functions evaluates to nil in IELM. The issue nonetheless persists.

[phoe]

The error message described in #2115 is the same as this one though.

[sdwolfz]

@phoe If you comment out this line: https://github.com/syl20bnr/spacemacs/blob/c7a103a772d808101d7635ec10f292ab9202d9ee/layers/+spacemacs/spacemacs-completion/packages.el#L29 the problem goes away.

But helm will no longer open in a side window on the lower side, taking up the entire frame width, it will instead split the current window.

[sdwolfz]

@phoe @thierryvolpiatto This issue can be closed as the problem lies in Spacemacs entirely. Thank you for investigating!

[phoe]

@sdwolfz This is a decent workaround - at least the tab button works. Thanks!

[phoe]

Closing as per @sdwolfz request.