Add error messages for missing variables when :strict

History.md

@@ -3,6 +3,7 @@
 ## 3.0.0 / not yet released / branch "master"
 
 * ...
+* Add error messages for missing variables when :strict, see #352 [Daniel Gaiottino]
 * Fix broken rendering of variables which are equal to false, see #345 [Florian Weingarten, fw42]
 * Remove ActionView template handler [Dylan Thacker-Smith, dylanahsmith]
 * Freeze lots of string literals for new Ruby 2.1 optimization, see #297 [Florian Weingarten, fw42]

lib/liquid/context.rb

@@ -203,6 +203,7 @@ module Liquid
         end
 
         scope     ||= @environments.last || @scopes.last
+        handle_not_found(key) unless scope.has_key?(key)
         variable  ||= lookup_and_evaluate(scope, key)
 
         variable = variable.to_liquid
@@ -252,6 +253,7 @@ module Liquid
               # No key was present with the desired value and it wasn't one of the directly supported
               # keywords either. The only thing we got left is to return nil
             else
+              handle_not_found(markup)
               return nil
             end
 
@@ -281,6 +283,10 @@ module Liquid
           end
         end
       end # squash_instance_assigns_with_environments
+
+      def handle_not_found(variable)
+        @errors << "Variable {{#{variable}}} not found" if Template.error_mode == :strict
+      end
   end # Context
 
 end # Liquid

test/unit/context_unit_test.rb

@@ -457,4 +457,22 @@ class ContextUnitTest < Test::Unit::TestCase
     assert_kind_of CategoryDrop, @context['category']
     assert_equal @context, @context['category'].context
   end
+
+  def test_strict_variables_not_found
+    with_error_mode(:strict) do
+      @context['does_not_exist']
+      assert(@context.errors.length == 1)
+      assert_equal(@context.errors[0], 'Variable {{does_not_exist}} not found')
+    end
+  end
+
+  def test_strict_nested_variables_not_found
+    with_error_mode(:strict) do
+      @context['hash'] = {'this' => 'exists'}
+      @context['hash.does_not_exist']
+      assert(@context.errors.length == 1)
+      assert_equal(@context.errors[0], 'Variable {{hash.does_not_exist}} not found')
+    end
+  end
+
 end # ContextTest