YCM causes some error while loading nerdtree

Question

I'm using vim to do my code job and I installed Nerdtree and YCM.

With this merge, YCM has two functions, which allows us to get the error and warning counts.

Here is my .vimrc:

autocmd VimEnter * NERDTree
autocmd CursorHold,CursorHoldI * update
set statusline+=%#warningmsg#
set statusline+=%{youcompleteme#GetErrorCount()}
set statusline+=%*

However, when I execute vim, I will get some errors as below:

Error detected while processing function 191[2]..192[20]..195[8]..159[25]..157[23]..nerdtree#echo[1]..youcompleteme#GetEr
rorCount:
line    1:
Traceback (most recent call last):
Press ENTER or type command to continue
Error detected while processing function 191[2]..192[20]..195[8]..159[25]..157[23]..nerdtree#echo[1]..youcompleteme#GetEr
rorCount:
line    1:
  File "<string>", line 1, in <module>
Press ENTER or type command to continue
Error detected while processing function 191[2]..192[20]..195[8]..159[25]..157[23]..nerdtree#echo[1]..youcompleteme#GetEr
rorCount:
line    1:
NameError: name 'ycm_state' is not defined
Press ENTER or type command to continue
Error detected while processing function 191[2]..192[20]..195[8]..159[25]..157[23]..nerdtree#echo[1]..youcompleteme#GetEr
rorCount:
line    1:
E858: Eval did not return a valid python object

Then, I type enter, everything works fine, I can see the error counts at the status line.

I don't quite know why but it seems that when I execute vim, it first loads the plugin Nerdtree, and the function youcompleteme#GetErrorCount() cause some error. After typing enter, it loads some files into buffer, then youcompleteme#GetErrorCount() can work well.

Can we solve this issue?

Answer 1

Well, I can't figure out exactly what the problem is but the reason probably is YCM is not ready while loading Nerdtree. So I add a if condition to check if YCM is ready.

set statusline+=%#warningmsg#
function! YCMStatusLine() abort
    if exists(':YcmDiag')
        let l:errCounts = youcompleteme#GetErrorCount()
        let l:wrnCounts = youcompleteme#GetWarningCount()

        return printf(
        \   '%dW %dE',
        \   wrnCounts,
        \   errCounts,
        \)
    endif
    return ''
endfunction
set statusline+=%{YCMStatusLine()}
set statusline+=%*

If :YcmDiag exists, it means that YCM has been loaded, if not, return an empty string.