diff --git a/autoload/classpath.vim b/autoload/classpath.vim
index e60e67b..fa3f9a9 100644
--- a/autoload/classpath.vim
+++ b/autoload/classpath.vim
@@ -54,7 +54,7 @@ function! classpath#detect(...) abort
     let root = simplify(fnamemodify(bufname(buffer), ':p:s?[\/]$??'))
   endif
 
-  if root =~# '^zipfile:'
+  if !isdirectory(fnamemodify(root, ':h'))
     return default
   endif
 
diff --git a/plugin/foreplay.vim b/plugin/foreplay.vim
index afcf0dc..7e1cc89 100644
--- a/plugin/foreplay.vim
+++ b/plugin/foreplay.vim
@@ -848,9 +848,12 @@ augroup END
 
 function! s:hunt(start, anchor) abort
   let root = simplify(fnamemodify(a:start, ':p:s?[\/]$??'))
+  if !isdirectory(fnamemodify(root, ':p'))
+    return ''
+  endif
   let previous = ""
   while root !=# previous
-    if filereadable(root . '/' .a:anchor) && isdirectory(root . '/src')
+    if filereadable(root . '/' . a:anchor) && isdirectory(root . '/src')
       return root
     endif
     let previous = root