From 6bdf88a32c8d732c6f5a1f2b0dd0576c172591bc Mon Sep 17 00:00:00 2001
From: Matt Rose <rose.matt@gmail.com>
Date: Thu, 29 Sep 2022 00:32:43 -0400
Subject: [PATCH] Add ability to pass tags to parse_context

---
 History.md                   |  3 +++
 lib/liquid/block_body.rb     |  9 +++++----
 lib/liquid/parse_context.rb  |  3 ++-
 test/integration/tag_test.rb | 31 +++++++++++++++++++++++++++++++
 4 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/History.md b/History.md
index 65e29243..536eed02 100644
--- a/History.md
+++ b/History.md
@@ -1,5 +1,8 @@
 # Liquid Change Log
 
+### Features
+* Add ability to pass `tags` to parse context to take precedence over `Liquid::Template.tags`
+
 ## 5.4.0 2022-07-29
 
 ### Breaking Changes
diff --git a/lib/liquid/block_body.rb b/lib/liquid/block_body.rb
index a0d35a79..6022324c 100644
--- a/lib/liquid/block_body.rb
+++ b/lib/liquid/block_body.rb
@@ -45,7 +45,7 @@ module Liquid
           end
           tag_name = Regexp.last_match(1)
           markup   = Regexp.last_match(2)
-          unless (tag = registered_tags[tag_name])
+          unless (tag = registered_tag(tag_name, parse_context))
             # end parsing if we reach an unknown tag and let the caller decide
             # determine how to proceed
             return yield tag_name, markup
@@ -132,7 +132,7 @@ module Liquid
             next
           end
 
-          unless (tag = registered_tags[tag_name])
+          unless (tag = registered_tag(tag_name, parse_context))
             # end parsing if we reach an unknown tag and let the caller decide
             # determine how to proceed
             return yield tag_name, markup
@@ -248,8 +248,9 @@ module Liquid
       BlockBody.raise_missing_variable_terminator(token, parse_context)
     end
 
-    def registered_tags
-      Template.tags
+    def registered_tag(tag_name, parse_context)
+      context_tag = parse_context.tags[tag_name] if parse_context.tags.respond_to?(:[])
+      context_tag || Template.tags[tag_name]
     end
   end
 end
diff --git a/lib/liquid/parse_context.rb b/lib/liquid/parse_context.rb
index 87570ad5..afd4ea53 100644
--- a/lib/liquid/parse_context.rb
+++ b/lib/liquid/parse_context.rb
@@ -2,7 +2,7 @@
 
 module Liquid
   class ParseContext
-    attr_accessor :locale, :line_number, :trim_whitespace, :depth
+    attr_accessor :locale, :line_number, :trim_whitespace, :depth, :tags
     attr_reader :partial, :warnings, :error_mode
 
     def initialize(options = {})
@@ -10,6 +10,7 @@ module Liquid
 
       @locale   = @template_options[:locale] ||= I18n.new
       @warnings = []
+      @tags = @template_options[:tags]
 
       self.depth   = 0
       self.partial = false
diff --git a/test/integration/tag_test.rb b/test/integration/tag_test.rb
index 6e28eb52..71d851f2 100644
--- a/test/integration/tag_test.rb
+++ b/test/integration/tag_test.rb
@@ -42,4 +42,35 @@ class TagTest < Minitest::Test
       assert_equal(buf.object_id, output.object_id)
     end
   end
+
+  def test_tags_can_be_overwritten_using_parse_context
+    tag_name = 'testtag'
+
+    original_tag = Class.new(Block) do
+      def render(*)
+        'original_tag'
+      end
+    end
+
+    new_tag = Class.new(Block) do
+      def render(*)
+        'new_tag'
+      end
+    end
+
+    tags_overwrite = Liquid::Template::TagRegistry.new
+    tags_overwrite[tag_name] = new_tag
+
+    with_custom_tag(tag_name, original_tag) do
+      liquid = "{% #{tag_name} %} {% end#{tag_name} %}"
+
+      template = Liquid::Template.parse(liquid)
+      assert_equal('original_tag', template.render)
+
+      unless ENV['LIQUID_C'] == '1'
+        template_with_overwrite = Liquid::Template.parse(liquid, tags: tags_overwrite)
+        assert_equal('new_tag', template_with_overwrite.render)
+      end
+    end
+  end
 end