timer with highlight breaks IncSearch

[dylnmc]

Hello,

With the handy assistance of a kind soul, who goes by the name m_ben, on freenode/#vim, we have deduced that a timer that repeatedly calls highlight makes IncSearch disappear when the timer's callback is called. For example, if you have a timer that repeatedly calls this every 200 ms or so, then you try to search for something with /set (for example), then IncSearch disappears when the timer is called. At first I thought it was the timer's fault, but it appears to happen only when highlight is issued. Therefore, it seems to be his fault.

What follows is a simple script that will cause the issue. In order to run it, copy the code below; open a new vim buffer; run :setf vim to change the filetype to vim; then save it with, for example, :w /tmp/foo.vim; run :source %; and finally, try to search for something (for example /state) and notice how IncSearch disappears when the statusline changes color. Here is the script:

let s:state = 0

function! BlinkStatus(timer) abort
    if s:state ==  0
        highlight StatusLine ctermbg=22 ctermfg=244 guibg=#005f00 guifg=#808080
        let s:state = 1
    else
        highlight StatusLine ctermfg=22 ctermbg=244 guifg=#005f00 guibg=#808080
        let s:state = 0
    endif
endfunction

let timer = timer_start(500, 'BlinkStatus', {'repeat': -1})

In order to test before I knew exactly what the issue is, I also made a small repository on gitlab that illustrates the problem: gitlab repo. In order to run that, just:

1. BE SURE TO SAVE YOUR OWN ~/.vimrc AND ~/.vim
2. git clone https://gitlab.com/dylnmc/vim-timer-test ~/.vim
3. vim and :PlugDownload
4. :XMas
5. Search for something ... notice how it breaks whenever you type any character in the search line

---

It doesn't matter unless you're version is pre 8.0, but my version is 8.1 with patches 1-591

Cheers,
dylnmc

[brammool]

With the handy assistance of a kind soul, who goes by the name `m_ben`, on freenode/#vim, we have deduced that a timer that repeatedly calls `highlight` makes `IncSearch` disappear when the timer's callback is called. For example, if you have a timer that repeatedly calls this every 200 ms or so, then you try to search for something with `/set` (for example), then `IncSearch` disappears when the timer is called. At first I thought it was the timer's fault, but it appears to happen only when `highlight` is issued. Therefore, it seems to be `hi`s fault. What follows is a simple script that will cause the issue. In order to run it, copy the code below, open a new vim buffer, run `:setf vim` to change the filetype to *vim*, then save it with, for example, `:w /tmp/foo.vim', and finally run `:source %`. Here is the script: ```vim let s:state = 0 function! BlinkStatus(timer) abort if s:state == 0 highlight StatusLine ctermbg=22 ctermfg=244 guibg=#005f00 guifg=#808080 let s:state = 1 else highlight StatusLine ctermfg=22 ctermbg=244 guifg=#005f00 guibg=#808080 let s:state = 0 endif endfunction let timer = timer_start(500, 'BlinkStatus', {'repeat': -1}) ``` In order to test before I knew exactly what the issue is, I also made a small repository on gitlab that illustrates the problem: [gitlab repo](https://gitlab.com/dylnmc/vim-timer-test). In order to run **that**, just: 1. **BE SURE TO SAVE YOUR OWN ~/.vimrc AND ~/.vim** 2. `git clone https://gitlab.com/dylnmc/vim-timer-test ~/.vim` 3. `vim` and `:PlugDownload` 4. `:XMas` 5. Search for something ... notice how it breaks whenever you type any character in the search line --- It doesn't matter unless you're version is pre 8.0, but my version is 8.1 with patches 1-591

Hmm, using :highlight from a timer will trigger a complete redraw, since Vim assumes something changed color. That means any temporary highlighting or text will be overwritten. This will be hard to avoid. I would suggest you don't change highlighting in a timer.

…

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[dylnmc]

I mean … sure I won't use highlight in a timer, since I don't need to. I don't know if you want me to close this issue or not. It still seems to be an issue, but it's definitely not an important issue or a time-sensitive one.

[dylnmc]

@brammool I just noticed (in 9.1 +1-956 so slightly older version) that terminals that update a lot (for example :terminal with weechat running, cause the same issue. Seems to slightly escalate the issue.

[brammool]

What do you mean with "makes IncSearch disappear"? Does the highlight group disappear?
I tried the example and a search highlight doesn't disappear, thus I don't understand the problem.

[dylnmc]

I had, for example, in a :terminal window weechat running and inside weechat there was a clock which updated every second. every time the timer changed IncSearch hl group disappeared. If the terminal doesn't update, then it appears not to break it. Also it might be a windows-only thing.

[GopherJ]

I'm wondering if this is related: https://files.gitter.im/5c7cd365d73408ce4fb98b75/K5kE/Peek-2020-07-06-11-46.gif

I have this issue in vim8.2 but not in neovim, I fixed it using:

:hi clear IncSearch