Stop rendering after a Liquid nesting limit error

lib/liquid/block_body.rb

@@ -95,6 +95,10 @@ def self.rescue_render_node(context, output, line_number, exc, blank_tag)
       case exc
       when MemoryError
         raise
+      when StackLevelError
+        # Nesting is a resource limit; continuing can multiply work exponentially.
+        context.handle_error(exc, line_number)
+        raise
       when UndefinedVariable, UndefinedDropMethod, UndefinedFilter
         context.handle_error(exc, line_number)
       else

test/integration/error_handling_test.rb

@@ -328,7 +328,10 @@ def test_error_is_raised_during_parse_with_template_name
       },
     )
 
-    assert_equal("Liquid error (some/path/snippet line 1): Nesting too deep", template.render(context))
+    error = assert_raises(Liquid::StackLevelError) do
+      template.render(context)
+    end
+    assert_equal("Liquid error (some/path/snippet line 1): Nesting too deep", error.to_s)
   end
 
   def test_internal_error_is_raised_with_template_name

test/integration/security_test.rb

@@ -96,4 +96,29 @@ def test_more_than_max_depth_nested_blocks_raises_exception
       Template.parse(code).render!
     end
   end
+
+  def test_recursive_includes_fail_fast_on_stack_level_error
+    with_block_max_depth(4) do
+      file_system = StubFileSystem.new(
+        "recurse" => "({% include 'recurse' %})\n[{% include 'recurse' %}]",
+      )
+      template = Template.parse("{% include 'recurse' %}", error_mode: :lax)
+
+      assert_raises(Liquid::StackLevelError) do
+        template.render({}, registers: { file_system: file_system })
+      end
+    end
+  end
+
+  private
+
+  def with_block_max_depth(depth)
+    original_depth = Liquid::Block::MAX_DEPTH
+    Liquid::Block.send(:remove_const, :MAX_DEPTH)
+    Liquid::Block.const_set(:MAX_DEPTH, depth)
+    yield
+  ensure
+    Liquid::Block.send(:remove_const, :MAX_DEPTH)
+    Liquid::Block.const_set(:MAX_DEPTH, original_depth)
+  end
 end # SecurityTest