Fix #27

autoload/coiledsnake.vim

@@ -170,13 +170,10 @@ function! coiledsnake#LoadSettings() abort "{{{1
 endfunction
 
 function! coiledsnake#EnableFoldText() abort "{{{1
-    let w:coiled_snake_saved_foldtext = &foldtext
     let &foldtext = 'coiledsnake#FoldText()'
 endfunction
 
 function! coiledsnake#EnableFoldExpr() abort "{{{1
-    let w:coiled_snake_saved_foldexpr = &foldexpr
-    let w:coiled_snake_saved_foldmethod = &foldmethod
     let &foldexpr = 'coiledsnake#FoldExpr(v:lnum)'
     let &foldmethod = 'expr'
     augroup CoiledSnake
@@ -185,12 +182,12 @@ function! coiledsnake#EnableFoldExpr() abort "{{{1
 endfunction
 
 function! coiledsnake#ResetFoldText() abort "{{{1
-    let &foldtext = get(w:, 'coiled_snake_saved_foldtext', &foldtext)
+    let &foldtext = &g:foldtext
 endfunction
 
 function! coiledsnake#ResetFoldExpr() abort "{{{1
-    let &foldexpr = get(w:, 'coiled_snake_saved_foldexpr', &foldexpr)
-    let &foldmethod = get(w:, 'coiled_snake_saved_foldmethod', &foldmethod)
+    let &foldexpr = &g:foldexpr
+    let &foldmethod = &g:foldmethod
     augroup CoiledSnake
         autocmd! TextChanged,InsertLeave <buffer>
     augroup END

ftplugin/python/coiledsnake.vim

@@ -0,0 +1,6 @@
+if exists('b:coiled_snake_should_fold')
+    finish
+endif
+let b:coiled_snake_should_fold = 1
+
+" vim: ts=4 sts=4 sw=4 fdm=marker et sr

plugin/coiledsnake.vim

@@ -1,9 +1,12 @@
-function! s:OnFileType() " {{{1
-    if ! get(b:, 'coiled_snake_bufenter', 0)
-        " Don't do anything before the buffer has been loaded.
+function! s:OnBufEnter() " {{{1
+    if ! (exists('b:coiled_snake_should_fold') && b:coiled_snake_should_fold)
+        " not python
         return
-    elseif &filetype != 'python' || &diff
-        " Don't do anything if this isn't a python file.
+    endif
+    if ! (&foldmethod ==# &g:foldmethod
+                \&& &foldexpr ==# &g:foldexpr
+                \&& &foldmethod ==# &g:foldmethod)
+        " something is not at default value. not safe to fold.
         return
     endif
 
@@ -17,20 +20,17 @@ function! s:OnFileType() " {{{1
     endif
 endfunction
 
-function! s:OnBufEnter() " {{{1
-    let b:coiled_snake_bufenter = 1
-    call s:OnFileType()
-endfunction
-
 function! s:OnBufLeave() " {{{1
     call coiledsnake#ResetFoldText()
     call coiledsnake#ResetFoldExpr()
 endfunction
 
 augroup CoiledSnake " {{{1
+    autocmd!
     autocmd FileType * call s:OnFileType()
     autocmd BufEnter * call s:OnBufEnter()
     autocmd BufLeave * call s:OnBufLeave()
 augroup END
+" }}}1
 
 " vim: ts=4 sts=4 sw=4 fdm=marker et sr