diff --git a/Library/Homebrew/dev-cmd/dispatch-build-bottle.rb b/Library/Homebrew/dev-cmd/dispatch-build-bottle.rb
index 21d5af7617..e5b325c918 100644
--- a/Library/Homebrew/dev-cmd/dispatch-build-bottle.rb
+++ b/Library/Homebrew/dev-cmd/dispatch-build-bottle.rb
@@ -35,14 +35,14 @@ module Homebrew
   def dispatch_build_bottle
     args = dispatch_build_bottle_args.parse
 
-    odie "Must specify --macos option" unless args.macos
-
-    macos = begin
-      MacOS::Version.from_symbol(args.macos.to_sym)
+    macos = args.macos&.yield_self do |s|
+      MacOS::Version.from_symbol(s.to_sym)
     rescue MacOSVersionError
-      MacOS::Version.new(args.macos)
+      MacOS::Version.new(s)
     end
 
+    raise UsageError, "Must specify --macos option" unless macos
+
     tap = Tap.fetch(args.tap || CoreTap.instance.name)
     user, repo = tap.full_name.split("/")