From c6e0c1e4903f72bb8ae7f0c274634939d76863a7 Mon Sep 17 00:00:00 2001
From: Florian Weingarten <flo@shopify.com>
Date: Wed, 8 Jan 2014 13:00:53 -0500
Subject: [PATCH 1/2] Fix resource counting bug with respond_to?(:length)

---
 lib/liquid/block.rb          |  2 +-
 lib/liquid/context.rb        |  8 ++++++++
 lib/liquid/tags/assign.rb    |  2 +-
 lib/liquid/tags/capture.rb   |  2 +-
 test/liquid/template_test.rb | 14 ++++++++++++++
 5 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/lib/liquid/block.rb b/lib/liquid/block.rb
index 0281b91..d1356eb 100644
--- a/lib/liquid/block.rb
+++ b/lib/liquid/block.rb
@@ -135,7 +135,7 @@ module Liquid
           end
 
           token_output = (token.respond_to?(:render) ? token.render(context) : token)
-          context.resource_limits[:render_length_current] += (token_output.respond_to?(:length) ? token_output.length : 1)
+          context.increment_used_resources(:render_length_current, token_output)
           if context.resource_limits_reached?
             context.resource_limits[:reached] = true
             raise MemoryError.new("Memory limits exceeded")
diff --git a/lib/liquid/context.rb b/lib/liquid/context.rb
index 2687dab..ade5c6d 100644
--- a/lib/liquid/context.rb
+++ b/lib/liquid/context.rb
@@ -28,6 +28,14 @@ module Liquid
       @filters = []
     end
 
+    def increment_used_resources(key, obj)
+      @resource_limits[key] += if obj.class.ancestors & [ String, Array, Hash ] != []
+        obj.length
+      else
+        1
+      end
+    end
+
     def resource_limits_reached?
       (@resource_limits[:render_length_limit] && @resource_limits[:render_length_current] > @resource_limits[:render_length_limit]) ||
       (@resource_limits[:render_score_limit]  && @resource_limits[:render_score_current]  > @resource_limits[:render_score_limit] ) ||
diff --git a/lib/liquid/tags/assign.rb b/lib/liquid/tags/assign.rb
index 0af0976..4699a6a 100644
--- a/lib/liquid/tags/assign.rb
+++ b/lib/liquid/tags/assign.rb
@@ -25,7 +25,7 @@ module Liquid
     def render(context)
       val = @from.render(context)
       context.scopes.last[@to] = val
-      context.resource_limits[:assign_score_current] += (val.respond_to?(:length) ? val.length : 1)
+      context.increment_used_resources(:assign_score_current, val)
       ''
     end
 
diff --git a/lib/liquid/tags/capture.rb b/lib/liquid/tags/capture.rb
index 92b9950..34036be 100644
--- a/lib/liquid/tags/capture.rb
+++ b/lib/liquid/tags/capture.rb
@@ -27,7 +27,7 @@ module Liquid
     def render(context)
       output = super
       context.scopes.last[@to] = output
-      context.resource_limits[:assign_score_current] += (output.respond_to?(:length) ? output.length : 1)
+      context.increment_used_resources(:assign_score_current, output)
       ''
     end
 
diff --git a/test/liquid/template_test.rb b/test/liquid/template_test.rb
index 5fd4d1e..f9afac1 100644
--- a/test/liquid/template_test.rb
+++ b/test/liquid/template_test.rb
@@ -14,6 +14,14 @@ class TemplateContextDrop < Liquid::Drop
   end
 end
 
+class SomethingWithLength
+  def length
+    nil
+  end
+
+  liquid_methods :length
+end
+
 class TemplateTest < Test::Unit::TestCase
   include Liquid
 
@@ -86,6 +94,12 @@ class TemplateTest < Test::Unit::TestCase
     @global = nil
   end
 
+  def test_resource_limits_works_with_custom_length_method
+    t = Template.parse("{% assign foo = bar %}")
+    t.resource_limits = { :render_length_limit => 42 }
+    assert_equal "", t.render("bar" => SomethingWithLength.new)
+  end
+
   def test_resource_limits_render_length
     t = Template.parse("0123456789")
     t.resource_limits = { :render_length_limit => 5 }

From 62a86a25aec745466c8bb372680ab19082245827 Mon Sep 17 00:00:00 2001
From: Florian Weingarten <flo@shopify.com>
Date: Wed, 8 Jan 2014 13:37:24 -0500
Subject: [PATCH 2/2] update history

---
 History.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/History.md b/History.md
index 4b114c1..8b77e2a 100644
--- a/History.md
+++ b/History.md
@@ -3,6 +3,7 @@
 ## 3.0.0 / not yet released / branch "master"
 
 * ...
+* Fix resource counting bug with respond_to?(:length), see #263 [Florian Weingarten, fw42]
 * Allow specifying custom patterns for template filenames, see #284 [Andrei Gladkyi, agladkyi]
 * Allow drops to optimize loading a slice of elements, see #282 [Tom Burns, boourns]
 * Support for passing variables to snippets in subdirs, see #271 [Joost Hietbrink, joost]