From 3d5d219522cee81304ec8cb1d6b37278e2761cb8 Mon Sep 17 00:00:00 2001
From: LCD 47 <lcd047@gmail.com>
Date: Thu, 16 Oct 2014 09:56:29 +0300
Subject: [PATCH] SyntasticInfo: if the current file will not be checked,
 explain why.

---
 plugin/syntastic.vim | 38 ++++++++++++++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/plugin/syntastic.vim b/plugin/syntastic.vim
index 18727e15..e78a94d8 100644
--- a/plugin/syntastic.vim
+++ b/plugin/syntastic.vim
@@ -19,7 +19,7 @@ if has('reltime')
     lockvar! g:syntastic_start
 endif
 
-let g:syntastic_version = '3.5.0-66'
+let g:syntastic_version = '3.5.0-67'
 lockvar g:syntastic_version
 
 " Sanity checks {{{1
@@ -180,10 +180,11 @@ command! -nargs=* -complete=custom,s:CompleteCheckerName SyntasticCheck
             \ call syntastic#util#redraw(g:syntastic_full_redraws)
 command! Errors call s:ShowLocList()
 command! -nargs=? -complete=custom,s:CompleteFiletypes SyntasticInfo
-            \ call s:modemap.modeInfo(<f-args>) |
-            \ call s:registry.echoInfoFor(s:resolveFiletypes(<f-args>))
+            \ call s:modemap.modeInfo(<f-args>) <bar>
+            \ call s:registry.echoInfoFor(s:resolveFiletypes(<f-args>)) <bar>
+            \ call s:explainSkip(<f-args>)
 command! SyntasticReset
-            \ call s:ClearCache() |
+            \ call s:ClearCache() <bar>
             \ call s:notifiers.refresh(g:SyntasticLoclist.New([]))
 command! SyntasticSetLoclist call g:SyntasticLoclist.current().setloclist()
 
@@ -582,6 +583,35 @@ function! s:skipFile() " {{{2
     return skip
 endfunction " }}}2
 
+" Explain why checks will be skipped for the current file
+function! s:explainSkip(...) " {{{2
+    if !a:0 && s:skipFile()
+        let why = []
+        let fname = expand('%')
+
+        if get(b:, 'syntastic_skip_checks', 0)
+            call add(why, 'b:syntastic_skip_checks set')
+        endif
+        if &buftype != ''
+            call add(why, 'buftype = ' . string(&buftype))
+        endif
+        if !filereadable(fname)
+            call add(why, 'file not readable / not local')
+        endif
+        if getwinvar(0, '&diff')
+            call add(why, 'diff mode')
+        endif
+        if s:ignoreFile(fname)
+            call add(why, 'filename matching g:syntastic_ignore_files')
+        endif
+        if fnamemodify(fname, ':e') =~? g:syntastic_ignore_extensions
+            call add(why, 'extension matching g:syntastic_ignore_extensions')
+        endif
+
+        echomsg 'The current file will not be checked (' . join(why, ', ') . ')'
+    endif
+endfunction " }}}2
+
 " Take a list of errors and add default values to them from a:options
 function! s:addToErrors(errors, options) " {{{2
     for err in a:errors