diff --git a/xmake/core/base/option.lua b/xmake/core/base/option.lua
index 9873d81953e..fee465a537b 100644
--- a/xmake/core/base/option.lua
+++ b/xmake/core/base/option.lua
@@ -726,9 +726,9 @@ end
 -- get the boolean value
 function option.boolean(value)
     if type(value) == "string" then
-        value = value:lower()
-        if value == "true" or value == "yes" or value == "y" then value = true
-        elseif value == "false" or value == "no" or value == "n" then value = false
+        local v = value:lower()
+        if v == "true" or v == "yes" or v == "y" then value = true
+        elseif v == "false" or v == "no" or v == "n" then value = false
         end
     end
     return value