起因
因为在维护 SpaceVim 这一项目，虽然我自己目前日常使用 neovim-0.9.5，但是还有不少用户会使用 neovim-nightly 版本。 因此，升级至每日构建版本测试 SpaceVim。
升级 Neovim
Windows 下升级也比较简单，使用 scoop 命令即可：
scoop uninstall neovim
scoop install neovim-nightly
不兼容的改动
安装后，启动一堆错误，也做了一部分修复，commits 如下：
* 2ad0da42 - perf(treesitter): add default setup function (Eric Wong 49 minutes ago)
* f8b280e0 - fix(flygrep): remove `t_ve` option (Eric Wong 68 minutes ago)
* c46968d5 - fix(colorscheme): link WinSeparator to VertSplit (Eric Wong 79 minutes ago)
* 9ee8606e - fix(telescope): fix deoplete autocmd (Eric Wong 82 minutes ago)
* 74c93c6c - chore(treesitter): update nvim-treesitter to 0.9.1 for Nvim-0.8.x (Eric Wong 2 hours ago)
vim.o.v_te 报错
原先，在我的代码里有很多通过设置 &v_te 选项来实现修改光标的造型。但是升级到新版本后，就报如下错误：
Error detected while processing function SpaceVim#plugins#flygrep#open:
line 1:
E5108: Error executing lua C:\Users\wsdjeg\.SpaceVim\/lua/spacevim/plugin/flygrep.lua:780: Unknown option 't_ve'
stack traceback:
[C]: in function '__index'
C:\Users\wsdjeg\.SpaceVim\/lua/spacevim/plugin/flygrep.lua:780: in function 'open'
[string ":lua"]:1: in main chunk
检查了下源码，原来是因为执行了 vim.o.v_te，尝试做了一些测试，增加exists()判断，可恨的是 exists('&t_ve') 居然返回 1。
那么就无法判断了，只能是删除这些设置。
窗口分割高亮 VertSplit 失效
更新后，分割窗口的竖线没有高亮了。查了下 :hi VertSplit，输出结果显示高亮设置正常。看了 :h hl-VertSplit 才知道，原来分割窗口的高亮组名称修改了。
修改成了 WinSeparator。因此在 ColorScheme 的 autocmd 内增加了：
hi link WinSeparator VertSplit
treesitter 高亮报错
这是我遇到最无语的错误。每当打开 lua 文件、help 文件 就会弹出报错 treesitter parser 不存在。起初我以为是 nvim-treesitter 的问题，更新并增加配置禁用所有的高亮都不行。
报错如下：
Error detected while processing function startify#open_buffers[13]..<SNR>276_open_buffer[12]..BufReadPost Autocommands for "*":
Error executing lua callback: ...s\neovim-nightly\current\share\nvim\runtime\filetype.lua:30: Error executing lua: ...s\neovim-nightly\current\share\nvim\runtime\filetype.lua:31: function startify#open_buffers[13]..<SNR>276_open_buffer[12]..BufReadPost Autocommands for "*"..FileType Autocommands for "*"..function <SNR>1_LoadFTPlugin[20]..script D:\Scoop\apps\neovim-nightly\current\share\nvim\runtime\ftplugin\lua.lua: Vim(runtime):E5113: Error while calling lua chunk: ...rrent\share\nvim\runtime/lua/vim/treesitter/language.lua:104: no parser for 'lua' language, see :help treesitter-parsers
stack traceback:
[C]: in function 'error'
...rrent\share\nvim\runtime/lua/vim/treesitter/language.lua:104: in function 'add'
...t\share\nvim\runtime/lua/vim/treesitter/languagetree.lua:112: in function 'new'
...ightly\current\share\nvim\runtime/lua/vim/treesitter.lua:41: in function '_create_parser'
...ightly\current\share\nvim\runtime/lua/vim/treesitter.lua:108: in function 'get_parser'
...ightly\current\share\nvim\runtime/lua/vim/treesitter.lua:416: in function 'start'
...ovim-nightly\current\share\nvim\runtime\ftplugin\lua.lua:2: in main chunk
执行 :help treesitter-parsers 同样报错，理解为打开 help 文件也报错，同只执行 :h。
Error detected while processing modelines[274]..FileType Autocommands for "*"..function <SNR>1_LoadFTPlugin[20]..script D:\Scoop\apps\neovim-nightly\current\share\nvim\runtime\ftplugin\help.lua:
E5113: Error while calling lua chunk: ...rrent\share\nvim\runtime/lua/vim/treesitter/language.lua:104: no parser for 'vimdoc' language, see :help treesitter-parsers
stack traceback:
[C]: in function 'error'
...rrent\share\nvim\runtime/lua/vim/treesitter/language.lua:104: in function 'add'
...t\share\nvim\runtime/lua/vim/treesitter/languagetree.lua:112: in function 'new'
...ightly\current\share\nvim\runtime/lua/vim/treesitter.lua:41: in function '_create_parser'
...ightly\current\share\nvim\runtime/lua/vim/treesitter.lua:108: in function 'get_parser'
...ightly\current\share\nvim\runtime/lua/vim/treesitter.lua:416: in function 'start'
...vim-nightly\current\share\nvim\runtime\ftplugin\help.lua:2: in main chunk
于是，禁用 SpaceVim 的 treesitter 模块，任然报错。查看了 neovim-nightly 的源码，发现，原来在这几个文件里面默认增加了：vim.treesitter.start()
D:\Scoop\apps\neovim-nightly\current\share\nvim\runtime\ftplugin\help.luaD:/Scoop/apps/neovim-nightly/0.10.0-2559/share/nvim/runtime/ftplugin/lua.lua- 等等，懒得去一个个搜了。
执行 cat D:/Scoop/apps/neovim-nightly/0.10.0-2559/share/nvim/runtime/ftplugin/lua.lua， 发现就两行代码，也没有任何条件判断跟 error handle。
-- use treesitter over syntax
vim.treesitter.start()
切回稳定版
说实话，没空去这样试错。
scoop uninstall neovim-nightly
scoop install neovim
nvim --version
NVIM v0.9.5
Build type: RelWithDebInfo
LuaJIT 2.1.1703942320
Compilation: C:/Program Files (x86)/Microsoft Visual Studio/2019/Enterprise/VC/Tools/MSVC/14.29.30133/bin/Hostx64/x64/cl.exe /MD /Zi /O2 /Ob1 -W3 -wd4311 -wd4146 -DUNIT_TESTING -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_DEPRECATE -D_WIN32_WINNT=0x0602 -DMSWIN -DINCLUDE_GENERATED_DECLARATIONS -ID:/a/neovim/neovim/.deps/usr/include/luajit-2.1 -ID:/a/neovim/neovim/.deps/usr/include -ID:/a/neovim/neovim/.deps/usr/include -ID:/a/neovim/neovim/build/src/nvim/auto -ID:/a/neovim/neovim/build/include -ID:/a/neovim/neovim/build/cmake.config -ID:/a/neovim/neovim/src -ID:/a/neovim/neovim/.deps/usr/include -ID:/a/neovim/neovim/.deps/usr/include -ID:/a/neovim/neovim/.deps/usr/include -ID:/a/neovim/neovim/.deps/usr/include -ID:/a/neovim/neovim/.deps/usr/include -ID:/a/neovim/neovim/.deps/usr/include -ID:/a/neovim/neovim/.deps/usr/include
system vimrc file: "$VIM\sysinit.vim"
fall-back for $VIM: "C:/Program Files (x86)/nvim/share/nvim"
Run :checkhealth for more info