Allow Hash with default value or default proc to be used

lib/liquid/context.rb

@@ -159,16 +159,12 @@ module Liquid
     # fetches an object starting at the local scope and then moving up
     # the hierachy
     def find_variable(key)
-      @scopes.each do |scope|
-        if scope.has_key?(key)
-          variable = scope[key]
-          variable = scope[key] = variable.call(self) if variable.is_a?(Proc)
-          variable = variable.to_liquid
-          variable.context = self if variable.respond_to?(:context=)
-          return variable
-        end
-      end
-      nil
+      scope = @scopes[0..-2].find { |s| s.has_key?(key) } || @scopes.last
+      variable = scope[key]
+      variable = scope[key] = variable.call(self) if variable.is_a?(Proc)
+      variable = variable.to_liquid
+      variable.context = self if variable.respond_to?(:context=)
+      return variable
     end
 
     # resolves namespaced queries gracefully.

test/variable_test.rb

@@ -157,4 +157,16 @@ class VariableResolutionTest < Test::Unit::TestCase
     assert_equal 'bazbar', template.render
   end
 
+  def test_hash_with_default_proc
+    template = Template.parse(%|Hello {{ test }}|)
+    assigns = Hash.new { |h,k| raise "Unknown variable '#{k}'" }
+    assigns['test'] = 'Tobi'
+    assert_equal 'Hello Tobi', template.render!(assigns)
+    assigns.delete('test')
+    e = assert_raises(RuntimeError) {
+      template.render!(assigns)
+    }
+    assert_equal "Unknown variable 'test'", e.message
+  end
+
 end