feat(checkhealth): use "help" syntax, avoid tabpage #20879

- If Nvim was just started, don't create a new tab.
- Name the buffer "health://".
- Use "help" syntax instead of "markdown". It fits better, and
  eliminates various workarounds.
- Simplfy formatting, avoid visual noise.
- Don't print a "INFO" status, it is noisy.
- Drop the ":" after statuses, they are already UPPERCASE and highlighted.

4 files changed, 31 insertions, 36 deletions

diff --git a/runtime/autoload/health.vim b/runtime/autoload/health.vim
index a693868381..5fd4627b11 100644
--- a/runtime/autoload/health.vim
+++ b/runtime/autoload/health.vim
@@ -5,8 +5,13 @@ function! health#check(plugin_names) abort
         \ ? s:discover_healthchecks()
         \ : s:get_healthcheck(a:plugin_names)
 
-  " create scratch-buffer
-  execute 'tab sbuffer' nvim_create_buf(v:true, v:true)
+  " Create buffer and open in a tab, unless this is the default buffer when Nvim starts.
+  let emptybuf = (bufnr('$') == 1 && empty(getline(1)) && 1 == line('$'))
+  execute (emptybuf ? 'buffer' : 'tab sbuffer') nvim_create_buf(v:true, v:true)
+  if bufexists('health://')
+    bwipe health://
+  endif
+  file health://
   setfiletype checkhealth
 
   if empty(healthchecks)
@@ -38,7 +43,7 @@ function! health#check(plugin_names) abort
                 \ name, v:throwpoint, v:exception))
         endif
       endtry
-      let header = [name. ': ' . func, repeat('=', 72)]
+      let header = [repeat('=', 78), name .. ': ' .. func, '']
       " remove empty line after header from report_start
       let s:output = s:output[0] == '' ? s:output[1:] : s:output
       let s:output = header + s:output + ['']
@@ -47,8 +52,7 @@ function! health#check(plugin_names) abort
     endfor
   endif
 
-  " needed for plasticboy/vim-markdown, because it uses fdm=expr
-  normal! zR
+  " Clear the 'Running healthchecks...' message.
   redraw|echo ''
 endfunction
 
@@ -58,7 +62,7 @@ endfunction
 
 " Starts a new report.
 function! health#report_start(name) abort
-  call s:collect_output("\n## " . a:name)
+  call s:collect_output(printf("\n%s ~", a:name))
 endfunction
 
 " Indents lines *except* line 1 of a string if it contains newlines.
@@ -81,7 +85,7 @@ endfunction
 " Format a message for a specific report item.
 " a:1: Optional advice (string or list)
 function! s:format_report_message(status, msg, ...) abort " {{{
-  let output = '  - ' . a:status . ': ' . s:indent_after_line1(a:msg, 4)
+  let output = '- ' .. a:status .. (empty(a:status) ? '' : ' ') .. s:indent_after_line1(a:msg, 2)
 
   " Optional parameters
   if a:0 > 0
@@ -92,9 +96,9 @@ function! s:format_report_message(status, msg, ...) abort " {{{
 
     " Report each suggestion
     if !empty(advice)
-      let output .= "\n    - ADVICE:"
+      let output .= "\n  - ADVICE:"
       for suggestion in advice
-        let output .= "\n      - " . s:indent_after_line1(suggestion, 10)
+        let output .= "\n    - " . s:indent_after_line1(suggestion, 6)
       endfor
     endif
   endif
@@ -102,9 +106,9 @@ function! s:format_report_message(status, msg, ...) abort " {{{
   return s:help_to_link(output)
 endfunction " }}}
 
-" Use {msg} to report information in the current section
+" Reports a message as a listitem in the current section.
 function! health#report_info(msg) abort " {{{
-  call s:collect_output(s:format_report_message('INFO', a:msg))
+  call s:collect_output(s:format_report_message('', a:msg))
 endfunction " }}}
 
 " Reports a successful healthcheck.
diff --git a/runtime/ftplugin/checkhealth.vim b/runtime/ftplugin/checkhealth.vim
index 3d8e9ace1a..62a1970b4a 100644
--- a/runtime/ftplugin/checkhealth.vim
+++ b/runtime/ftplugin/checkhealth.vim
@@ -1,20 +1,18 @@
 " Vim filetype plugin
-" Language:     Neovim checkhealth buffer
-" Last Change:  2021 Dec 15
+" Language:     Nvim :checkhealth buffer
+" Last Change:  2022 Nov 10
 
 if exists("b:did_ftplugin")
   finish
 endif
 
-runtime! ftplugin/markdown.vim ftplugin/markdown_*.vim ftplugin/markdown/*.vim
+runtime! ftplugin/help.vim
 
 setlocal wrap breakindent linebreak
-setlocal conceallevel=2 concealcursor=nc
-setlocal keywordprg=:help
 let &l:iskeyword='!-~,^*,^|,^",192-255'
 
 if exists("b:undo_ftplugin")
-  let b:undo_ftplugin .= "|setl wrap< bri< lbr< cole< cocu< kp< isk<"
+  let b:undo_ftplugin .= "|setl wrap< bri< lbr< kp< isk<"
 else
-  let b:undo_ftplugin = "setl wrap< bri< lbr< cole< cocu< kp< isk<"
+  let b:undo_ftplugin = "setl wrap< bri< lbr< kp< isk<"
 endif
diff --git a/runtime/lua/nvim/health.lua b/runtime/lua/nvim/health.lua
index 413eae0bf9..0dd32ddc0b 100644
--- a/runtime/lua/nvim/health.lua
+++ b/runtime/lua/nvim/health.lua
@@ -359,14 +359,12 @@ local function check_terminal()
           \                   ..'\%(conemu\|vtpcon\|win32con\)')))
       call health#report_error('command failed: '.cmd."\n".out)
     else
-      call health#report_info('key_backspace (kbs) terminfo entry: '
-            \ .(empty(kbs_entry) ? '? (not found)' : kbs_entry))
-      call health#report_info('key_dc (kdch1) terminfo entry: '
-            \ .(empty(kbs_entry) ? '? (not found)' : kdch1_entry))
+      call health#report_info(printf('key_backspace (kbs) terminfo entry: `%s`', (empty(kbs_entry) ? '? (not found)' : kbs_entry)))
+      call health#report_info(printf('key_dc (kdch1) terminfo entry: `%s`', (empty(kbs_entry) ? '? (not found)' : kdch1_entry)))
     endif
     for env_var in ['XTERM_VERSION', 'VTE_VERSION', 'TERM_PROGRAM', 'COLORTERM', 'SSH_TTY']
       if exists('$'.env_var)
-        call health#report_info(printf("$%s='%s'", env_var, eval('$'.env_var)))
+        call health#report_info(printf('$%s="%s"', env_var, eval('$'.env_var)))
       endif
     endfor
   endf
diff --git a/runtime/syntax/checkhealth.vim b/runtime/syntax/checkhealth.vim
index 37f1822740..4b0ce75a54 100644
--- a/runtime/syntax/checkhealth.vim
+++ b/runtime/syntax/checkhealth.vim
@@ -1,26 +1,21 @@
 " Vim syntax file
-" Language:     Neovim checkhealth buffer
-" Last Change:  2021 Dec 15
+" Language:     Nvim :checkhealth buffer
+" Last Change:  2022 Nov 10
 
 if exists("b:current_syntax")
   finish
 endif
 
-runtime! syntax/markdown.vim
+runtime! syntax/help.vim
 unlet! b:current_syntax
 
 syn case match
 
-" We do not care about markdown syntax errors
-if hlexists('markdownError')
-  syn clear markdownError
-endif
-
-syn keyword healthError ERROR[:] containedin=markdownCodeBlock,mkdListItemLine
-syn keyword healthWarning WARNING[:] containedin=markdownCodeBlock,mkdListItemLine
-syn keyword healthSuccess OK[:] containedin=markdownCodeBlock,mkdListItemLine
-syn match healthHelp "|.\{-}|" containedin=markdownCodeBlock,mkdListItemLine contains=healthBar
-syn match healthBar  "|" contained conceal
+syn keyword healthError ERROR[:]
+syn keyword healthWarning WARNING[:]
+syn keyword healthSuccess OK[:]
+syn match helpSectionDelim "^======*\n.*$"
+syn match healthHeadingChar "=" conceal cchar=─ contained containedin=helpSectionDelim
 
 hi def link healthError Error
 hi def link healthWarning WarningMsg