为什么'indentexpr ='不断打印？

Question

["

I have made some modifications in my .vimrc (install some plugins, like for example fzf, include some extra configurations, etc).<\/i>

---

""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""      
"               
"               ██╗   ██╗██╗███╗   ███╗██████╗  ██████╗
"               ██║   ██║██║████╗ ████║██╔══██╗██╔════╝
"               ██║   ██║██║██╔████╔██║██████╔╝██║     
"               ╚██╗ ██╔╝██║██║╚██╔╝██║██╔══██╗██║     
"                ╚████╔╝ ██║██║ ╚═╝ ██║██║  ██║╚██████╗
"                 ╚═══╝  ╚═╝╚═╝     ╚═╝╚═╝  ╚═╝ ╚═════╝
"               
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

syntax on
set autoindent
set indentexpr

" Disable compatibility with vi which can cause unexpected issues.
set nocompatible
" Enable type file detection. Vim will be able to try to detect the type of file in use.
filetype on
" Enable plugins and load plugin for the detected file type.
filetype plugin on
" Load an indent file for the detected file type.
filetype indent on

set number
augroup numbertoggle
    autocmd!
    autocmd BufEnter,FocusGained,InsertLeave,WinEnter * if &nu && mode() != "i" | set rnu   | endif
    autocmd BufLeave,FocusLost,InsertEnter,WinLeave   * if &nu                  | set nornu | endif
augroup END

set tabstop=4 softtabstop=4
set shiftwidth=4
set noerrorbells

" Use space characters instead of tabs.
set expandtab
" Do not save backup files.
set nobackup
" Do not let cursor scroll below or above N number of lines when scrolling.
set scrolloff=10
" Do not wrap lines. Allow long lines to extend as far as the line goes.
"set nowrap

" While searching though a file incrementally highlight matching characters as you type.
set incsearch
" Ignore capital letters during search.
"set ignorecase
" Override the ignorecase option if searching for capital letters.
" This will allow you to search specifically for capital letters.
set smartcase
" Use highlighting when doing a search.
set hlsearch

" Show partial command you type in the last line of the screen.
set showmode
" Show matching words during a search.
"set showmatch
" Set the commands to save in history default number is 20.
"set history=1000
set nu
set nowrap
set smartcase
set noswapfile
set undodir=~/.vim/undoir
set undofile
" Enable auto completion menu after pressing TAB.
set wildmenu
" Make wildmenu behave like similar to Bash completion.
set wildmode=list:longest
" There are certain files that we would never want to edit with Vim.
" Wildmenu will ignore files with these extensions.
set wildignore=*.docx,*.jpg,*.png,*.gif,*.pdf,*.pyc,*.exe,*.flv,*.img,*.xlsx

set colorcolumn=80
highlight ColorColumn ctermbg=0 guibg=lightgrey
colorscheme PaperColor 
set background=light

let g:vim_be_good_log_file = 1
let g:vim_apm_log = 1

if executable('rg')
    let g:rg_derive_root='true'
endif

let loaded_matchparen = 1

set splitbelow
set splitright

nmenu Misc.Beautify.For :s/for\s*(\s*/for ( /<CR>:s/\s*)\s*$/ )/<CR>:s/\(\i\+\)\s*=\s*/\1 = /<CR>:s/\s*\([=<>!]=\\|[<>]\)\s*/ \1 /<CR>:s/\s*\(--\\|++\)/\1/<CR>:s/\s*;\s*/; /g<CR>
nmenu Misc.Beautify.Func :s/\s*)/ )/g<CR>:s/\s*\([(,]\)\s*/\1 /g<CR>:s/(\s\+)/()/g<CR>
nmenu Misc.Beautify.If :s/if\s*(\s*/if ( /<CR>:s/\s*)\s*$/ )/<CR>:silent s/\s*\([=<>!]=\\|[<>]\)\s*/ \1 /<CR>
nmenu Misc.Beautify.Assign :s/\s*\([-+*\/&\|]\?\)\s*=\s*/ \1= /g<CR>

" MAPPINGS --------------------------------------------------------------- {{{

" Set the backslash as the leader key.
let mapleader = '\'

" Press \\ to jump back to the last cursor position.
nnoremap <leader>\ ``
inoremap jj <Esc>

" Press the space bar to type the : character in command mode.
nnoremap <space> :

"CTRL + S to save
nmap <c-s> :w<CR>
vmap <c-s> <Esc><c-s>gv
imap <c-s> <Esc><c-s>

"CTRL + Z to undo
nnoremap <c-z> :u<CR>      " Avoid using this**
inoremap <c-z> <c-o>:u<CR>

" Move in tabs
nnoremap <C-Left> :tabprevious<CR>                                                                            
nnoremap <C-Right> :tabnext<CR>
nnoremap <C-j> :tabprevious<CR>                                                                            
nnoremap <C-k> :tabnext<CR>

" CTRL-Tab is next tab
noremap <C-Tab> :<C-U>tabnext<CR>
inoremap <C-Tab> <C-\><C-N>:tabnext<CR>
cnoremap <C-Tab> <C-C>:tabnext<CR>
" CTRL-SHIFT-Tab is previous tab
noremap <C-S-Tab> :<C-U>tabprevious<CR>
inoremap <C-S-Tab> <C-\><C-N>:tabprevious<CR>
cnoremap <C-S-Tab> <C-C>:tabprevious<CR>

" Split navigation
nnoremap <C-J> <C-W><C-J>
nnoremap <C-K> <C-W><C-K>
nnoremap <C-L> <C-W><C-L>
nnoremap <C-H> <C-W><C-H>

" }}}

" PLUGINS ---------------------------------------------------------------- {{{

call plug#begin('~/.vim/plugged')

Plug 'tpope/vim-fugitive'
Plug 'preservim/nerdtree'
Plug 'neoclide/coc.nvim', {'branch': 'release'}
Plug 'vim-airline/vim-airline'
Plug 'vim-airline/vim-airline-themes'
Plug 'junegunn/fzf.vim'
Plug 'othree/yajs.vim', { 'for': 'javascript' }
Plug 'mxw/vim-jsx'
Plug 'elzr/vim-json'
Plug 'vim-syntastic/syntastic'
Plug 'ctrlpvim/ctrlp.vim'

call plug#end()

" }}}

" PLUG-CtrlP ---------------------------------------------------------------- {{{

set wildignore+=*/tmp/*,*.so,*.swp,*.zip   
set runtimepath^=~/.vim/bundle/ctrlp.vim
let g:ctrlp_map = '<c-p>'
let g:ctrlp_cmd = 'CtrlP'
let g:ctrlp_working_path_mode = 'ra'
let g:ctrlp_user_command = 'find %s -type f'
let g:ctrlp_map = '<c-p>'
let g:ctrlp_cmd = 'CtrlP'

" use current git repo/file director with ctrl p
let g:ctrlp_working_path_mode = 'ra'

" }}}

" PLUG-Airline ---------------------------------------------------------------- {{{

let g:airline#extensions#tagbar#enabled = 1
let g:airline#extensions#tagbar#flags = ''

let g:airline_theme='luna'

let g:airline_section_z = "%p%% : \ue0a1:%l/%L: Col:%c"

" Configure the Tabline
let g:airline#extensions#tmuxline#enabled = 0
let g:airline#extensions#tabline#formatter = 'default'
let g:airline_section_x=''
let g:airline_skip_empty_sections = 1

" }}}

" PLUG-COC ---------------------------------------------------------------- {{{

" Set internal encoding of vim, not needed on neovim, since coc.nvim using some
" unicode characters in the file autoload/float.vim
set encoding=utf-8

" TextEdit might fail if hidden is not set.
set hidden

" Some servers have issues with backup files, see #649.
set nobackup
set nowritebackup

" Give more space for displaying messages.
set cmdheight=2

" Having longer updatetime (default is 4000 ms = 4 s) leads to noticeable
" delays and poor user experience.
set updatetime=300

" Don't pass messages to |ins-completion-menu|.
set shortmess+=c

" Always show the signcolumn, otherwise it would shift the text each time
" diagnostics appear/become resolved.
if has("nvim-0.5.0") || has("patch-8.1.1564")
    " Recently vim can merge signcolumn and number column into one
    set signcolumn=number
else
    set signcolumn=yes
endif

" Use tab for trigger completion with characters ahead and navigate.
" NOTE: Use command ':verbose imap <tab>' to make sure tab is not mapped by
" other plugin before putting this into your config.
inoremap <silent><expr> <TAB>
            \ pumvisible() ? "\<C-n>" :
            \ <SID>check_back_space() ? "\<TAB>" :
            \ coc#refresh()
inoremap <expr><S-TAB> pumvisible() ? "\<C-p>" : "\<C-h>"

function! s:check_back_space() abort
    let col = col('.') - 1
    return !col || getline('.')[col - 1]  =~# '\s'
endfunction

" Use <c-space> to trigger completion.
if has('nvim')
    inoremap <silent><expr> <c-space> coc#refresh()
else
    inoremap <silent><expr> <c-@> coc#refresh()
endif

" Make <CR> auto-select the first completion item and notify coc.nvim to
" format on enter, <cr> could be remapped by other vim plugin
inoremap <silent><expr> <cr> pumvisible() ? coc#_select_confirm()
            \: "\<C-g>u\<CR>\<c-r>=coc#on_enter()\<CR>"

" Use `[g` and `]g` to navigate diagnostics
" Use `:CocDiagnostics` to get all diagnostics of current buffer in location list.
nmap <silent> [g <Plug>(coc-diagnostic-prev)
nmap <silent> ]g <Plug>(coc-diagnostic-next)

" GoTo code navigation.
nmap <silent> gd <Plug>(coc-definition)
nmap <silent> gy <Plug>(coc-type-definition)
nmap <silent> gi <Plug>(coc-implementation)
nmap <silent> gr <Plug>(coc-references)

" Use K to show documentation in preview window.
nnoremap <silent> K :call <SID>show_documentation()<CR>

function! s:show_documentation()
    if (index(['vim','help'], &filetype) >= 0)
        execute 'h '.expand('<cword>')
    elseif (coc#rpc#ready())
        call CocActionAsync('doHover')
    else
        execute '!' . &keywordprg . " " . expand('<cword>')
    endif
endfunction

" Highlight the symbol and its references when holding the cursor.
autocmd CursorHold * silent call CocActionAsync('highlight')

" Symbol renaming.
nmap <leader>rn <Plug>(coc-rename)

" Formatting selected code.
xmap <leader>f  <Plug>(coc-format-selected)
nmap <leader>f  <Plug>(coc-format-selected)

augroup mygroup
    autocmd!
    " Setup formatexpr specified filetype(s).
    autocmd FileType typescript,json setl formatexpr=CocAction('formatSelected')
    " Update signature help on jump placeholder.
    autocmd User CocJumpPlaceholder call CocActionAsync('showSignatureHelp')
augroup end

" Applying codeAction to the selected region.
" Example: `<leader>aap` for current paragraph
xmap <leader>a  <Plug>(coc-codeaction-selected)
nmap <leader>a  <Plug>(coc-codeaction-selected)

" Remap keys for applying codeAction to the current buffer.
nmap <leader>ac  <Plug>(coc-codeaction)
" Apply AutoFix to problem on the current line.
nmap <leader>qf  <Plug>(coc-fix-current)

" Run the Code Lens action on the current line.
nmap <leader>cl  <Plug>(coc-codelens-action)

" Map function and class text objects
" NOTE: Requires 'textDocument.documentSymbol' support from the language server.
xmap if <Plug>(coc-funcobj-i)
omap if <Plug>(coc-funcobj-i)
xmap af <Plug>(coc-funcobj-a)
omap af <Plug>(coc-funcobj-a)
xmap ic <Plug>(coc-classobj-i)
omap ic <Plug>(coc-classobj-i)
xmap ac <Plug>(coc-classobj-a)
omap ac <Plug>(coc-classobj-a)

" Remap <C-f> and <C-b> for scroll float windows/popups.
if has('nvim-0.4.0') || has('patch-8.2.0750')
    nnoremap <silent><nowait><expr> <C-f> coc#float#has_scroll() ? coc#float#scroll(1) : "\<C-f>"
    nnoremap <silent><nowait><expr> <C-b> coc#float#has_scroll() ? coc#float#scroll(0) : "\<C-b>"
    inoremap <silent><nowait><expr> <C-f> coc#float#has_scroll() ? "\<c-r>=coc#float#scroll(1)\<cr>" : "\<Right>"
    inoremap <silent><nowait><expr> <C-b> coc#float#has_scroll() ? "\<c-r>=coc#float#scroll(0)\<cr>" : "\<Left>"
    vnoremap <silent><nowait><expr> <C-f> coc#float#has_scroll() ? coc#float#scroll(1) : "\<C-f>"
    vnoremap <silent><nowait><expr> <C-b> coc#float#has_scroll() ? coc#float#scroll(0) : "\<C-b>"
endif

" Use CTRL-S for selections ranges.
" Requires 'textDocument/selectionRange' support of language server.
"nmap <silent> <C-s> <Plug>(coc-range-select)
"xmap <silent> <C-s> <Plug>(coc-range-select)

" Add `:Format` command to format current buffer.
command! -nargs=0 Format :call CocActionAsync('format')

" Add `:Fold` command to fold current buffer.
command! -nargs=? Fold :call     CocAction('fold', <f-args>)

" Add `:OR` command for organize imports of the current buffer.
command! -nargs=0 OR   :call     CocActionAsync('runCommand', 'editor.action.organizeImport')

" Add (Neo)Vim's native statusline support.
" NOTE: Please see `:h coc-status` for integrations with external plugins that
" provide custom statusline: lightline.vim, vim-airline.
set statusline^=%{coc#status()}%{get(b:,'coc_current_function','')}

" Mappings for CoCList
" Show all diagnostics.
nnoremap <silent><nowait> <space>a  :<C-u>CocList diagnostics<cr>
" Manage extensions.
nnoremap <silent><nowait> <space>e  :<C-u>CocList extensions<cr>
" Show commands.
nnoremap <silent><nowait> <space>c  :<C-u>CocList commands<cr>
" Find symbol of current document.
nnoremap <silent><nowait> <space>o  :<C-u>CocList outline<cr>
" Search workspace symbols.
nnoremap <silent><nowait> <space>s  :<C-u>CocList -I symbols<cr>
" Do default action for next item.
nnoremap <silent><nowait> <space>j  :<C-u>CocNext<CR>
" Do default action for previous item.
nnoremap <silent><nowait> <space>k  :<C-u>CocPrev<CR>
" Resume latest coc list.
nnoremap <silent><nowait> <space>p  :<C-u>CocListResume<CR>"

" }}}

" PLUG-FZF ---------------------------------------------------------------- {{{

" Default fzf layout
" - Popup window (center of the screen)
let g:fzf_layout = { 'window': { 'width': 0.9, 'height': 0.6 } }

" - Popup window (center of the current window)
let g:fzf_layout = { 'window': { 'width': 0.9, 'height': 0.6, 'relative': v:true } }

" - Popup window (anchored to the bottom of the current window)
let g:fzf_layout = { 'window': { 'width': 0.9, 'height': 0.6, 'relative': v:true, 'yoffset': 1.0 } }

" - down / up / left / right
let g:fzf_layout = { 'down': '40%' }

" - Window using a Vim command
let g:fzf_layout = { 'window': 'enew' }
let g:fzf_layout = { 'window': '-tabnew' }
let g:fzf_layout = { 'window': '10new' }

" }}}

" PLUGINS-JSX ---------------------------------------------------------------- {{{

let g:jsx_ext_required = 1

" }}}

" PLUG-NERDTree ---------------------------------------------------------------- {{{

" Refresh the current folder if any changes
autocmd BufEnter NERD_tree_* | execute 'normal R'
au CursorHold * if exists("t:NerdTreeBufName") | call <SNR>15_refreshRoot() | endif

"Reload the window if directory is changed
augroup DIRCHANGE
    au!
    autocmd DirChanged global :NERDTreeCWD
augroup END

"Close nerdtree automatically if it is theonly window open
autocmd bufenter * if (winnr("$") == 1 && exists("b:NERDTree") && b:NERDTree.isTabTree()) | q | endif

" }}}

" PLUG-Syntastic ---------------------------------------------------------------- {{{

set statusline+=%#warningmsg#
set statusline+=%{SyntasticStatuslineFlag()}
set statusline+=%*
let g:syntastic_always_populate_loc_list = 1
let g:syntastic_auto_loc_list = 1
let g:syntastic_check_on_open = 1
let g:syntastic_check_on_wq = 0

" }}}

" VIMSCRIPT -------------------------------------------------------------- {{{

" Enable the marker method of folding.
augroup filetype_vim
    autocmd!
    autocmd FileType vim setlocal foldmethod=marker
augroup END

" If the current file type is HTML, set indentation to 2 spaces.
autocmd Filetype html setlocal tabstop=2 shiftwidth=2 expandtab

" If Vim version is equal to or greater than 7.3 enable undofile.
" This allows you to undo changes to a file even after saving it.
if version >= 703
    set undodir=~/.vim/backup
    set undofile
    set undoreload=10000
endif

" You can split a window into sections by typing `:split` or `:vsplit`.
" Display cursorline and cursorcolumn ONLY in active window.
augroup cursor_off
    autocmd!
    autocmd WinLeave * set nocursorline nocursorcolumn
    autocmd WinEnter * set cursorline cursorcolumn
augroup END

" }}}

Answer 1

Line 14:

set indentexpr

That command prints the value of indentexpr :

indentexpr=         " value is empty
indentexpr=Foo()    " value is Foo()

Since you have that command in your vimrc , the value is output every time your vimrc is sourced. Remove it.

As for why you get that string so often, maybe a stray autocommand?