cnoremap <CR> <CR> breaks search fold opening

Question

In order to switch between relative and absolute line numbering upon entering command-line, I noremap <expr> <CR> to "someStuff".

Unfortunately this breaks the foldopen-ing feature for forward searches.

It already happens with the following line

cnoremap <CR> <CR>

MWE

entire .vimrc

set foldmethod=marker
"default foldopen
set foldopen=block,hor,mark,percent,quickfix,search,tag,undo
cnoremap <CR> <CR>

text file

{{{
lkj
}}}

maneuver : normal-mode-type /lkj<CR>

and the fold does not open

comment the cnoremap reload and do the same, the fold does open

Attempts

I somewhat managed to walk around the issue with a silly hack such as :

cnoremap <CR> <CR>i<C-c>

unfortunately this breaks the repeat (.) history.

The following works :

cnoremap <CR> <CR>mf.u`f

except at the opening of a vim session, when the . repeat does nothing.

Is there some way to achieve the cnoremapping <CR> <CR> in a fully transparent way ?

Answer 1

As :h 'foldopen' states:

NOTE: When the command is part of a mapping this option is not used. Add the |zv| command to the mapping to get the same effect. (rationale: the mapping may want to control opening folds itself)

So you should add the zv to your mapping, e.g. cnoremap <cr> <cr>zv