From 1aaf6ed0198ba18e1d714f521581a9c921c68635 Mon Sep 17 00:00:00 2001
From: Michael Go <michael.go@shopify.com>
Date: Mon, 30 Jan 2023 18:32:23 -0400
Subject: [PATCH] recursively parse brackets on variable lookup

---
 lib/liquid.rb                     |  2 +-
 test/integration/variable_test.rb | 22 ++++++++++++++++++++++
 test/test_helper.rb               | 11 +++++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/lib/liquid.rb b/lib/liquid.rb
index 5eda04e7..09b0dd80 100644
--- a/lib/liquid.rb
+++ b/lib/liquid.rb
@@ -41,7 +41,7 @@ module Liquid
   AnyStartingTag              = /#{TagStart}|#{VariableStart}/o
   PartialTemplateParser       = /#{TagStart}.*?#{TagEnd}|#{VariableStart}.*?#{VariableIncompleteEnd}/om
   TemplateParser              = /(#{PartialTemplateParser}|#{AnyStartingTag})/om
-  VariableParser              = /\[[^\]]+\]|#{VariableSegment}+\??/o
+  VariableParser              = /\[(?:[^\[\]]+|\g<0>)*\]|#{VariableSegment}+\??/o
 
   RAISE_EXCEPTION_LAMBDA = ->(_e) { raise }
 
diff --git a/test/integration/variable_test.rb b/test/integration/variable_test.rb
index c007f1f5..192a3fe9 100644
--- a/test/integration/variable_test.rb
+++ b/test/integration/variable_test.rb
@@ -135,4 +135,26 @@ class VariableTest < Minitest::Test
   def test_raw_value_variable
     assert_template_result('bar', '{{ [key] }}', { 'key' => 'foo', 'foo' => 'bar' })
   end
+
+  def test_dynamic_find_var_with_drop
+    assert_template_result(
+      'bar',
+      '{{ [list[settings.zero]] }}',
+      {
+        'list' => ['foo'],
+        'settings' => SettingsDrop.new("zero" => 0),
+        'foo' => 'bar',
+      }
+    )
+
+    assert_template_result(
+      'foo',
+      '{{ [list[settings.zero]["foo"]] }}',
+      {
+        'list' => [{ 'foo' => 'bar' }],
+        'settings' => SettingsDrop.new("zero" => 0),
+        'bar' => 'foo',
+      }
+    )
+  end
 end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 49b1cc76..c1514bb3 100755
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -125,6 +125,17 @@ class ThingWithToLiquid
   end
 end
 
+class SettingsDrop < Liquid::Drop
+  def initialize(settings)
+    super()
+    @settings = settings
+  end
+
+  def liquid_method_missing(key)
+    @settings[key]
+  end
+end
+
 class IntegerDrop < Liquid::Drop
   def initialize(value)
     super()