From ad3748af21a7f697d8db3b76f83a391c7069b166 Mon Sep 17 00:00:00 2001
From: Dylan Thacker-Smith <Dylan.Smith@shopify.com>
Date: Thu, 21 May 2015 16:49:18 -0400
Subject: [PATCH] Include template name with line numbers in render errors.

---
 lib/liquid/context.rb                   |  3 ++-
 lib/liquid/errors.rb                    |  5 +++-
 lib/liquid/tags/include.rb              | 33 ++++++++++++++-----------
 test/integration/error_handling_test.rb | 20 +++++++++++++++
 4 files changed, 45 insertions(+), 16 deletions(-)

diff --git a/lib/liquid/context.rb b/lib/liquid/context.rb
index c761d089..bb52558e 100644
--- a/lib/liquid/context.rb
+++ b/lib/liquid/context.rb
@@ -13,7 +13,7 @@ module Liquid
   #   context['bob']  #=> nil  class Context
   class Context
     attr_reader :scopes, :errors, :registers, :environments, :resource_limits
-    attr_accessor :exception_handler
+    attr_accessor :exception_handler, :template_name
 
     def initialize(environments = {}, outer_scope = {}, registers = {}, rethrow_errors = false, resource_limits = nil)
       @environments     = [environments].flatten
@@ -64,6 +64,7 @@ module Liquid
 
     def handle_error(e, token = nil)
       if e.is_a?(Liquid::Error)
+        e.template_name = template_name
         e.set_line_number_from_token(token)
       end
 
diff --git a/lib/liquid/errors.rb b/lib/liquid/errors.rb
index e1defc5f..f1d4a2d4 100644
--- a/lib/liquid/errors.rb
+++ b/lib/liquid/errors.rb
@@ -1,6 +1,7 @@
 module Liquid
   class Error < ::StandardError
     attr_accessor :line_number
+    attr_accessor :template_name
     attr_accessor :markup_context
 
     def to_s(with_prefix = true)
@@ -41,7 +42,9 @@ module Liquid
       end
 
       if line_number
-        str << " (line #{line_number})"
+        str << " ("
+        str << template_name << " " if template_name
+        str << "line " << line_number.to_s << ")"
       end
 
       str << ": "
diff --git a/lib/liquid/tags/include.rb b/lib/liquid/tags/include.rb
index 80b46d93..3b1fc23d 100644
--- a/lib/liquid/tags/include.rb
+++ b/lib/liquid/tags/include.rb
@@ -41,9 +41,9 @@ module Liquid
     end
 
     def render(context)
-      partial = load_cached_partial(context)
-
       template_name = context.evaluate(@template_name_expr)
+      partial = load_cached_partial(template_name, context)
+
       context_variable_name = template_name.split('/'.freeze).last
 
       variable = if @variable_name_expr
@@ -52,28 +52,33 @@ module Liquid
         context.find_variable(template_name)
       end
 
-      context.stack do
-        @attributes.each do |key, value|
-          context[key] = context.evaluate(value)
-        end
+      old_template_name = context.template_name
+      begin
+        context.template_name = template_name
+        context.stack do
+          @attributes.each do |key, value|
+            context[key] = context.evaluate(value)
+          end
 
-        if variable.is_a?(Array)
-          variable.collect do |var|
-            context[context_variable_name] = var
+          if variable.is_a?(Array)
+            variable.collect do |var|
+              context[context_variable_name] = var
+              partial.render(context)
+            end
+          else
+            context[context_variable_name] = variable
             partial.render(context)
           end
-        else
-          context[context_variable_name] = variable
-          partial.render(context)
         end
+      ensure
+        context.template_name = old_template_name
       end
     end
 
     private
 
-    def load_cached_partial(context)
+    def load_cached_partial(template_name, context)
       cached_partials = context.registers[:cached_partials] || {}
-      template_name = context.evaluate(@template_name_expr)
 
       if cached = cached_partials[template_name]
         return cached
diff --git a/test/integration/error_handling_test.rb b/test/integration/error_handling_test.rb
index 61091804..6e2623f2 100644
--- a/test/integration/error_handling_test.rb
+++ b/test/integration/error_handling_test.rb
@@ -203,4 +203,24 @@ class ErrorHandlingTest < Minitest::Test
     assert_equal 'This is a runtime error: Liquid error (line 1): internal', output
     assert_equal [InternalError], template.errors.map(&:class)
   end
+
+  class TestFileSystem
+    def read_template_file(template_path)
+      "{{ errors.argument_error }}"
+    end
+  end
+
+  def test_included_template_name_with_line_numbers
+    old_file_system = Liquid::Template.file_system
+
+    begin
+      Liquid::Template.file_system = TestFileSystem.new
+      template = Liquid::Template.parse("Argument error:\n{% include 'product' %}", line_numbers: true)
+      page = template.render('errors' => ErrorDrop.new)
+    ensure
+      Liquid::Template.file_system = old_file_system
+    end
+    assert_equal "Argument error:\nLiquid error (product line 1): argument error", page
+    assert_equal "product", template.errors.first.template_name
+  end
 end