render error message with actual template path

lib/liquid/tags/include.rb

@@ -70,9 +70,15 @@ module Liquid
 
       old_template_name = context.template_name
       old_partial       = context.partial
+
       begin
-        context.template_name = template_name
-        context.partial       = true
+        context.template_name = if Template.file_system.respond_to?(:actual_template_name)
+          Template.file_system.actual_template_name(template_name).delete_suffix('.liquid')
+        else
+          template_name
+        end
+
+        context.partial = true
         context.stack do
           @attributes.each do |key, value|
             context[key] = context.evaluate(value)

lib/liquid/tags/render.rb

@@ -76,7 +76,13 @@ module Liquid
 
       render_partial_func = ->(var, forloop) {
         inner_context               = context.new_isolated_subcontext
-        inner_context.template_name = template_name
+
+        inner_context.template_name = if Template.file_system.respond_to?(:actual_template_name)
+          Template.file_system.actual_template_name(template_name).delete_suffix('.liquid')
+        else
+          template_name
+        end
+
         inner_context.partial       = true
         inner_context['forloop']    = forloop if forloop
 

test/integration/tags/include_tag_test.rb

@@ -356,4 +356,17 @@ class IncludeTagTest < Minitest::Test
       partials: { 'break' => "{% break %}" },
     )
   end
+
+  def test_include_tag_renders_actual_template_name_for_error
+    original_file_system = Liquid::Template.file_system
+
+    Liquid::Template.file_system = MemoryFileSystem.new(
+      '/some/path/snippets/foo.liquid' => "{{ foo.standard_error }}",
+    )
+
+    template = Liquid::Template.parse("{% include 'foo' with errors %}", line_numbers: true)
+    assert_equal('Liquid error (/some/path/snippets/foo line 1): standard error', template.render('errors' => ErrorDrop.new))
+  ensure
+    Liquid::Template.file_system = original_file_system
+  end
 end # IncludeTagTest

test/integration/tags/render_tag_test.rb

@@ -264,4 +264,17 @@ class RenderTagTest < Minitest::Test
       },
     )
   end
+
+  def test_render_tag_renders_actual_template_name_for_error
+    original_file_system = Liquid::Template.file_system
+
+    Liquid::Template.file_system = MemoryFileSystem.new(
+      '/some/path/snippets/foo.liquid' => "{{ foo.standard_error }}",
+    )
+
+    template = Liquid::Template.parse("{% render 'foo' with errors %}", line_numbers: true)
+    assert_equal('Liquid error (/some/path/snippets/foo line 1): standard error', template.render('errors' => ErrorDrop.new))
+  ensure
+    Liquid::Template.file_system = original_file_system
+  end
 end

test/test_helper.rb

@@ -214,3 +214,25 @@ class StubTemplateFactory
     Liquid::Template.new
   end
 end
+
+class MemoryFileSystem
+  def initialize(values)
+    # values is a hash of template_path => template_source
+    @snippets = {}
+    values.each do |file_path, source|
+      key = file_path.split('/').last.delete_suffix(".liquid")
+      @snippets[key] = {
+        source: source,
+        actual_template_name: file_path,
+      }
+    end
+  end
+
+  def read_template_file(template_name)
+    @snippets[template_name][:source]
+  end
+
+  def actual_template_name(template_name)
+    @snippets[template_name][:actual_template_name]
+  end
+end