diff --git a/plugin/tagbar.vim b/plugin/tagbar.vim
index 68bd702..a7e5e7e 100644
--- a/plugin/tagbar.vim
+++ b/plugin/tagbar.vim
@@ -2480,14 +2480,14 @@ function! s:AutoUpdate(fname)
         return
     endif
 
-    " Don't do anything if the file isn't supported
-    if !s:IsValidFile(a:fname, &filetype)
-        return
-    endif
-
     " Only consider the main filetype in cases like 'python.django'
     let ftype = split(&filetype, '\.')[0]
 
+    " Don't do anything if the file isn't supported
+    if !s:IsValidFile(a:fname, ftype)
+        return
+    endif
+
     " Process the file if it's unknown or the information is outdated
     " Also test for entries that exist but are empty, which will be the case
     " if there was an error during the ctags execution