From 8fc855986b888330a1d640d4df528f28a3b73d50 Mon Sep 17 00:00:00 2001
From: Lisa Ugray <lisa.ugray@shopify.com>
Date: Mon, 7 Jan 2019 08:13:56 -0500
Subject: [PATCH] ostruct.rb: refine arity failure message

* lib/ostruct.rb (method_missing): raise exceptions with proper arity
messages
---
 lib/ostruct.rb | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/ostruct.rb b/lib/ostruct.rb
index a758a65979..6eb794fcac 100644
--- a/lib/ostruct.rb
+++ b/lib/ostruct.rb
@@ -213,14 +213,15 @@ def method_missing(mid, *args) # :nodoc:
     len = args.length
     if mname = mid[/.*(?==\z)/m]
       if len != 1
-        raise ArgumentError, "wrong number of arguments (#{len} for 1)", caller(1)
+        raise ArgumentError, "wrong number of arguments (given #{len}, expected 1)", caller(1)
       end
       modifiable?[new_ostruct_member!(mname)] = args[0]
-    elsif len == 0 # and /\A[a-z_]\w*\z/ =~ mid #
-      if @table.key?(mid)
-        new_ostruct_member!(mid) unless frozen?
-        @table[mid]
+    elsif @table.key?(mid)
+      if len != 0
+        raise ArgumentError, "wrong number of arguments (given #{len}, expected 0)"
       end
+      new_ostruct_member!(mid) unless frozen?
+      @table[mid]
     else
       begin
         super
-- 
2.20.1