diff --git a/lua/flatten/core.lua b/lua/flatten/core.lua
index 5ff3b85..9f4d0a4 100644
--- a/lua/flatten/core.lua
+++ b/lua/flatten/core.lua
@@ -1,7 +1,9 @@
 local M = {}
 
 local function path_is_absolute(path)
-  path = string.gsub(path, "^%s+://", "")
+  if string.find(path, "^%a[%w.+-]*://") then
+    return true
+  end
 
   if jit.os == "Windows" then
     return string.find(path, "^%a:") ~= nil