Encapsulate b:git_dir

plugin/fugitive.vim

@@ -29,7 +29,7 @@ function! FugitiveCommonDir(...) abort
 endfunction
 
 function! FugitiveWorkTree(...) abort
-  return FugitiveTreeForGitDir(FugitiveGitDir(a:0 ? a:1 : -1))
+  return s:Tree(FugitiveGitDir(a:0 ? a:1 : -1))
 endfunction
 
 function! FugitiveReal(...) abort
@@ -110,7 +110,7 @@ endfunction
 
 let s:worktree_for_dir = {}
 let s:dir_for_worktree = {}
-function! FugitiveTreeForGitDir(path) abort
+function! s:Tree(path) abort
   let dir = a:path
   if dir =~# '/\.git$'
     return len(dir) ==# 5 ? '/' : dir[0:-6]
@@ -173,7 +173,7 @@ function! FugitiveExtractGitDir(path) abort
       return simplify(fnamemodify($GIT_DIR, ':p:s?[\/]$??'))
     endif
     if FugitiveIsGitDir($GIT_DIR)
-      call FugitiveWorkTree(simplify(fnamemodify($GIT_DIR, ':p:s?[\/]$??')))
+      call s:Tree(simplify(fnamemodify($GIT_DIR, ':p:s?[\/]$??')))
       if has_key(s:dir_for_worktree, root)
         return s:dir_for_worktree[root]
       endif
@@ -228,7 +228,7 @@ function! s:ProjectionistDetect() abort
   let dir = FugitiveExtractGitDir(file)
   let base = matchstr(file, '^fugitive://.\{-\}//\x\+')
   if empty(base)
-    let base = FugitiveTreeForGitDir(dir)
+    let base = s:Tree(dir)
   endif
   if len(base)
     if exists('+shellslash') && !&shellslash
@@ -251,21 +251,21 @@ augroup fugitive
   autocmd CmdWinEnter * call FugitiveDetect(expand('#:p'))
 
   autocmd FileType git
-        \ if exists('b:git_dir') |
+        \ if len(FugitiveGitDir()) |
         \   call fugitive#MapJumps() |
         \   call fugitive#MapCfile() |
         \ endif
   autocmd FileType gitcommit
-        \ if exists('b:git_dir') |
+        \ if len(FugitiveGitDir()) |
         \   call fugitive#MapCfile('fugitive#MessageCfile()') |
         \ endif
   autocmd FileType fugitive
-        \ if exists('b:git_dir') |
+        \ if len(FugitiveGitDir()) |
         \   call fugitive#MapCfile('fugitive#StatusCfile()') |
         \ endif
   autocmd FileType gitrebase
         \ let &l:include = '^\%(pick\|squash\|edit\|reword\|fixup\|drop\|[pserfd]\)\>' |
-        \ if exists('b:git_dir') |
+        \ if len(FugitiveGitDir()) |
         \   let &l:includeexpr = 'v:fname =~# ''^\x\{4,40\}$'' ? FugitiveFind(v:fname) : ' .
         \   (len(&l:includeexpr) ? &l:includeexpr : 'v:fname') |
         \ endif |