[bug] undo removes whole content of file even if I only open existing file a nothing is modified

[t...@verotel.cz]

## Expected behavior, english is required

With clear vim (or neovim) installation without "SpaceVim":

I open file with command: vim readme.txt (or: nvim readme.txt)

If the file is opened and I press "u" (undo) ...
(I may press multiple "undo"s),
then the editor shows status message "Already at oldest change"
and file content is not modified.

I expect that same "undo" functionality will be with SpaceVim.
So that I have original file content after "all undo calls".

## The reproduce ways from Vim starting (Required!)


If I do the same with clear installation of SpaceVim (basic):

I run from shell: vim readme.txt (or: nvim readme.txt)

Then I press "u" (i.e. undo) ... I may do multiple "undo"s,
then whole content of file is removed
and after that is displayed message "Already at oldest change".


## Environment Information

- OS: linux
- vim version: 8.2.2434
- neovim version: -
- SpaceVim version: 2.1.0-dev
- SpaceVim status: 5216b5ea

```
On branch master
Your branch is up to date with 'origin/master'.

nothing to commit, working tree clean
```

## The reproduce ways from Vim starting (Required!)

## Output of the `:SPDebugInfo!`

<details><summary> SpaceVim debug information </summary>

### SpaceVim options :

```toml
auto_disable_touchpad = 1
autocomplete_method = 'asyncomplete'
autocomplete_parens = 1
buffer_index_type = 4
checkinstall = 1
code_runner_focus = 0
colorscheme = 'gruvbox'
colorscheme_bg = 'dark'
colorscheme_default = 'desert'
commandline_prompt = '>'
custom_color_palette = []
custom_plugins = []
data_dir = '/home/developer/.cache/'
debug_level = 1
default_custom_leader = '<Space>'
default_indent = 2
disabled_plugins = []
enable_bepo_layout = 0
enable_cursorcolumn = 0
enable_cursorline = 1
enable_debug = 0
enable_googlesuggest = 0
enable_guicolors = 0
enable_javacomplete2_py = 0
enable_key_frequency = 0
enable_language_specific_leader = 1
enable_neocomplcache = 0
enable_os_fileformat_icon = 0
enable_powerline_fonts = 1
enable_projects_cache = 1
enable_statusline_bfpath = 0
enable_statusline_mode = 0
enable_statusline_tag = 1
enable_tabline_filetype_icon = 0
enable_tabline_ft_icon = 0
enable_vimfiler_welcome = 1
enable_ycm = 0
error_symbol = '✖'
escape_key_binding = 'jk'
expand_tab = 1
file_searching_tools = []
filemanager = 'nerdtree'
filetree_direction = 'right'
filetype_icons = {}
force_global_config = 0
gitcommit_issue_icon = ''
gitcommit_pr_icon = ''
github_username = ''
guifont = ''
hiddenfileinfo = 1
home_files_number = 6
hosts_url =
'https://raw.githubusercontent.com/racaljk/hosts/master/hosts'
info_symbol = 'ⓘ'
keep_server_alive = 1
language = ''
leader_guide_default_group_name = ''
leader_guide_flatten = 1
leader_guide_hspace = 5
leader_guide_max_size = 0
leader_guide_position = 'botright'
leader_guide_run_map_on_popup = 1
leader_guide_sort_horizontal = 0
leader_guide_submode_mappings = {'<C-C>': 'win_close'}
leader_guide_vertical = 0
lint_engine = 'neomake'
lint_on_save = 1
lint_on_the_fly = 0
max_column = 120
plugin_bundle_dir = '/home/developer/.cache/vimfiles/'
plugin_manager = 'dein'
plugin_manager_processes = 16
plugin_name = 'vim-grepper'
project_auto_root = 1
project_non_root = ''
project_rooter_outermost = 1
project_rooter_patterns = ['.git/', '_darcs/', '.hg/', '.bzr/',
'.svn/', '.SpaceVim.d/']
projects_cache_num = 20
realtime_leader_guide = 1
relativenumber = 1
search_tools = ['rg', 'ag', 'pt', 'ack', 'grep', 'findstr', 'git']
sidebar_direction = ''
sidebar_width = 30
smartcloseignoreft = ['tagbar', 'vimfiler', 'defx', 'NvimTree',
'SpaceVimRunner', 'SpaceVimREPL', 'SpaceVimQuickFix', 'HelpDescribe',
'VebuggerShell', 'VebuggerTerminal', 'SpaceVimTabsManager']
smartcloseignorewin = ['__Tagbar__', 'vimfiler:default']
snippet_engine = 'neosnippet'
src_root = 'E:\sources\'
statusline_iseparator = 'bar'
statusline_left = ['winnr', 'filename', 'major mode', 'search count',
'syntax checking', 'minor mode lighters']
statusline_right = ['fileformat', 'cursorpos', 'percentage']
statusline_separator = 'nil'
statusline_unicode = 0
terminal_cursor_shape = 2
todo_labels = ['fixme', 'question', 'todo', 'idea']
todo_prefix = '@'
update_retry_cnt = 3
version = '2.1.0-dev'
vim_help_language = 'en'
vimcompatible = 1
warning_symbol = '⚠'
wildignore =
'*/tmp/*,*.so,*.swp,*.zip,*.class,tags,*.jpg,*.ttf,*.TTF,*.png,*/target
/*,.git,.svn,.hg,.DS_Store,*.svg'
windisk_encoding = 'cp936'
windows_index_type = 3
windows_leader = ''
windows_smartclose = ''
wrap_line = 0
```


### SpaceVim layers :

```toml
[[layers]]
name="autocomplete"
auto_completion_return_key_behavior='complete'
auto_completion_tab_key_behavior='cycle'
[[layers]]
name="checkers"
[[layers]]
name="format"
[[layers]]
name="edit"
[[layers]]
name="ui"
[[layers]]
name="core"
[[layers]]
name="core#banner"
[[layers]]
name="core#statusline"
[[layers]]
name="core#tabline"
[[layers]]
name="shell"
default_position='top'
default_height=30
```


### SpaceVim Health checking :

SpaceVim clipboard support check report:
Checking +clipboard:
Failed : to support +clipboard, you need recompile your vim with
+clipboard support.
SpaceVim environment check report:
Current progpath: vi(/usr/bin/vim.basic)
version: 802
OS: linux
[shell, shellcmdflag, shellslash]: ['/bin/bash', '-c', 0]
SpaceVim lua support check report:
Checking +lua:
Failed : to support +lua, you need recompile your vim with +lua
support.
SpaceVim python support check report:
Checking +python3:
Failed : to support +python3, Please install vim-gtk, or build
from sources.
Checking +python:
Failed : to support +python, Please install vim-gtk, or build
from sources.
autocomplete layer health:

ok

checkers layer health:

ok

format layer health:

ok

edit layer health:

ok

ui layer health:

ok

core layer health:

ok

core#banner layer health:

ok

core#statusline layer health:

ok

core#tabline layer health:

ok

shell layer health:

ok


### SpaceVim runtime log :

```log
[ SpaceVim ] : logger file does not exists, only log for current
process will be shown!
[ SpaceVim ] [11:12:25] [ 0.000] [ Info ] Loading SpaceVim from:
/home/developer/.SpaceVim/
[ SpaceVim ] [11:12:25] [ 0.005] [ Info ] Startup with argv: ['vi',
'README.txt']
[ SpaceVim ] [11:12:25] [ 0.012] [ Info ] start loading global
config >>>
[ SpaceVim ] [11:12:25] [ 0.012] [ Info ] global_dir is:
/home/developer/.SpaceVim.d/
[ SpaceVim ] [11:12:25] [ 0.012] [ Info ] find global config:
/home/developer/.SpaceVim.d/init.toml
[ SpaceVim ] [11:12:25] [ 0.012] [ Info ] start to apply config
[glob]
[ SpaceVim ] [11:12:25] [ 0.013] [ Info ] current directory is
$HOME, skip local config
[ SpaceVim ] [11:12:25] [ 0.047] [ Info ] the func has been added to
mode:syntax-checking
[ SpaceVim ] [11:12:25] [ 0.077] [ Info ] the func has been added to
mode:spell-checking
[ SpaceVim ] [11:12:25] [ 0.077] [ Info ] the func has been added to
mode:paste-mode
[ SpaceVim ] [11:12:25] [ 0.120] [ Info ] finished loading SpaceVim!
[ rooter ] [11:12:25] [ 0.181] [ Info ] Load projects cache from:
/home/developer/.cache/SpaceVim/projects.json
[ rooter ] [11:12:31] [ 5.724] [ Info ] Start to find root for:
/tmp/vpqHvju/1/issue_report.md
[ SpaceVim ] [11:12:31] [ 5.765] [ Info ] the func has been added to
mode:syntax-checking
[ SpaceVim ] [11:12:31] [ 5.775] [ Info ] the func has been added to
mode:spell-checking
[ SpaceVim ] [11:12:31] [ 5.775] [ Info ] the func has been added to
mode:paste-mode
```

[Jeff zhao]

+1