[BUG]: Error E315 if 'splitbelow' option is set.

[VanLaser]

When using the splitbelow option, I get strange Vim internal errors (E315), for each line, when opening a help topic.

How to reproduce (minimal vimrc - I use vim-plug as plugin manager):

set nocompatible

filetype off
call plug#begin('~/.vim/plugged')
    Plug 'aserebryakov/filestyle'
call plug#end()

filetype plugin indent on
syntax on

set splitbelow

The errors look like:

:h syntax.txt
E315: ml_get: invalid lnum: 5319
E315: ml_get: invalid lnum: 5318
...
E315: ml_get: invalid lnum: 1

I suspect the wincmd w commands are to blame, but I don't know how to change them.

Thanks for the plugin!

[aserebryakov]

How critical issue is?

[aserebryakov]

The issue is confirmed (Vim 7.4 for Windows + Pathogen).

[VanLaser]

How critical issue is?

It's not critical, in that I can disable set splitbelow. It is critical, if you consider that set splitbelow is a standard Vim option that anyone should be able to use. In any case, thanks for confirming the issue.

Perhaps - just give an option not to hook/autocmd FileStyle... operations to any buffer by default, and allow/advice users how to do it selectively instead (only for their preferred filetypes)? Hooking to VimEnter etc. by default is a little intrusive. Or: avoid 'help', unlisted, or even all read-only buffers, if that's the only place where the bug appears? (just suggestions, if useful)

[aserebryakov]

I tried to reproduce the issue on Ubuntu version. It gives another error:

E434: Can't find tag pattern

[VanLaser]

I can make it happen (E315) on both Win7 x64 and ArchLinux (Vim 7.4, included patches 1-729).

[dennis-hamester]

I have the same problem and it's actually quite annoying. Similar to VanLaser, I'm also on Arch and use vim-plug. Another observation here is, that Local Additions in the help root file is empty now. Is there anything I can do to further help / debug this issue?

[aserebryakov]

In general, errors like E315 may mean bug in Vim itself, but anyway I will try to find workaround as soon as possible.

[aserebryakov]

@VanLaser, @dennishamester , can you please provide me the .vim and .vimrc to reproduce the issue in your environment?

[aserebryakov]

~~@VanLaser, @dennishamester, can you please check the following workaround:~~

~~Comment the wincmd w in the FileStyleDeactivate() function.~~

~~It looks like it fixes the issue in Windows.~~

[aserebryakov]

Commenting wincmd w in FileStyleDeactivate() totally breaks NerdTree.

[VanLaser]

After a quick test, it seems to work like this:

if !&splitbelow
    wincmd w
endif

(if I comment wincmd w unconditionally, I get the original error when option splitbelow is NOT set.

An alternative way (safer?) could be, perhaps, to save the splitbelow option value, unset it temporarily, run wincmd w, then set it back to the saved value, all those in a wrapper function, instead of the simple wincmd w command. Not tested, though, it may be too late to unset the option at that point.

[aserebryakov]

@VanLaser, as I mentioned before it can break NERDTree.