execute() should clear cmdline

[wsdjeg]

• nvim --version: master
• Vim (version: ) behaves differently? yes, in vim, it works well
• Operating system/version: arch
• Terminal name/version: termite
• $TERM: xterm-termite

Actual behaviour

execute() do not clear cmdline

Expected behaviour

execute() should clear cmdline

Steps to reproduce using nvim -u NORC

test.vim

let g:testvim_test = 'hello neovim'
let g:testoldversion = 0

fu! Test()
    let list = []
    if has('patch-7.4.2010') && !g:testoldversion
        for var in getcompletion('g:testvim_','var')
            call add(list, var . ' = ' . string(get(g:, var[2:] , '')))
        endfor
    else
        redraw
        for var in filter(map(s:execute('let g:'), "matchstr(v:val, '\\S\\+')"), "v:val =~# '^testvim_'")
            call add(list,'g:' . var . ' = ' . string(get(g:, var , '')))
        endfor
    endif
    return list
endf

function! s:execute(cmd) abort
  if exists('*execute')
    return split(execute(a:cmd), "\n")
  endif

  redir => output
  execute a:cmd
  redir END
  return split(output, "\n")
endfunction

reproduce step:

1. nvim -u test.vim
2. :echo Test()[0] get g:testvim_test = 'hello neovim'
3. :let g:testoldversion = 1
4. :echo Test()[0] get :echo Test()[0] g:testvim_test = 'hello neovim'

[wsdjeg]

this issue is found in SpaceVim/SpaceVim#186

[jamessan]

Can you test #5975?

[wsdjeg]

@jamessan I am not sure if it is some issue with my config, but it still does not work well for me.

[justinmk]

Why is this a problem? Avoiding redraws is a good thing. Can you call :redraw?

[wsdjeg]

@justinmk This is different in vim, and redraw does not work, the output still has echo Test() at the begin.

[justinmk]

Sorry, I misunderstood the report.

[justinmk]

I see the problem, this only happens if you :echo Test()[0] as a user from the cmdline. If you add this to the end of the script, then source the script:

:echo Test()[0]

There's no problem. Nor if you store the result in a variable and then echo the variable.

let g:a= Test()[0]

[wsdjeg]

yes, I have trid use let g:a= Test()[0] in my plugin, and it works, but I think this maybe a bug.

[justinmk]

It is a bug. It can be worked around by adding :redraw to the beginning of Test() (or anywhere before the call to execute()).

[wsdjeg]

I have trid to add redraw at the beginning of Test(), but it does not work, BTW, I am using neovim 0.1.7, and has('patch-7.4.2010') return 0。

[justinmk]

Hmm, confirmed. I would guess keep_msg is not being updated for some reason. Even with :redraw!, the column still isn't updated so it looks like this:

                        g:testvim_test = 'hello neovim'

[wsdjeg]

Thanks, and a easy way to reproduce is :
:echo type(execute('au'))

you will see
:echo type(execute('au')) 1
instead of
1

[liushapku]

Today I dug into the source code of both vim and neovim and identified the cause of difference: vim calls msg_col = 0 at the end of function f_execute() while neovim does not do that. Adding a msg_col = 0 to the end of f_execute() simply solves the problem.

---

Using @wsdjeg's test case I cannot see the problem, perhaps because I ran using nvim -u NONE and no autocmd is installed. I created the following test case which should be saved in a file and then in Ex mode, type :so {the_file}.

call execute('echo 12345678')
echo 'see where I am'

If the "see where I am" starts from col 1, then it is correct and compliant to vim's behavior. nvim will display the string from col 9.

[liushapku]

Acutally, simply set it to 0 will make the following echon behave differently. (vim also behaves incorrectly here)

I created a PR to fully address this issue.

A test script is saved at here. I don't know how to add test to the repo. Each call Testxa() should generate exactly the same result as call Testxb() where x=1,2,3,4.

[janlazo]

I tried patching vim-patch:8.1.0569 and vim-patch:8.1.0571 for this issue but the tests fail because assertion with value from screenchar. Anyone who wants to port them should consider lua tests instead if the screenchar tests in src/nvim/testdir/ are required for compatibility.