Disable rendering of tag based on register

lib/liquid.rb

@@ -78,8 +78,10 @@ require 'liquid/tokenizer'
 require 'liquid/parse_context'
 require 'liquid/partial_cache'
 require 'liquid/usage'
+require 'liquid/register'
 require 'liquid/static_registers'
 
 # Load all the tags of the standard library
 #
 Dir["#{__dir__}/liquid/tags/*.rb"].each { |f| require f }
+Dir["#{__dir__}/liquid/registers/*.rb"].each { |f| require f }

lib/liquid/locales/en.yml

@@ -25,3 +25,5 @@
       render: "Syntax error in tag 'render' - Template name must be a quoted string"
     argument:
       include: "Argument error in tag 'include' - Illegal template name"
+    disabled:
+      include: "'include' usage has been disabled in this context, consider using 'render'."

lib/liquid/register.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module Liquid
+  class Register
+  end
+end

lib/liquid/registers/disabled_tags.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+module Liquid
+  class DisabledTags < Register
+    def initialize
+      @disabled_tags = Hash.new { |h, k| h[k] = 0 }
+    end
+
+    def disabled?(tag)
+      @disabled_tags[tag] > 0
+    end
+
+    def disable(tag)
+      incr(tag)
+      yield
+    ensure
+      decr(tag)
+    end
+
+    private
+
+    def incr(tag)
+      @disabled_tags[tag] = @disabled_tags[tag] + 1
+    end
+
+    def decr(tag)
+      @disabled_tags[tag] = @disabled_tags[tag] - 1
+    end
+  end
+
+  Template.register_register('disabled_tags', DisabledTags.new)
+end

lib/liquid/tags/include.rb

@@ -45,6 +45,7 @@ module Liquid
     end
 
     def render_to_output_buffer(context, output)
+      return output << options[:locale].t("errors.disabled.include") if context.registers['disabled_tags']&.disabled?('include')
       template_name = context.evaluate(@template_name_expr)
       raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name
 

lib/liquid/tags/render.rb

@@ -22,6 +22,13 @@ module Liquid
     end
 
     def render_to_output_buffer(context, output)
+      context.registers['disabled_tags']&.disable('include') do
+        return render_tag(context, output)
+      end
+      render_tag(context, output)
+    end
+
+    def render_tag(context, output)
       # Though we evaluate this here we will only ever parse it as a string literal.
       template_name = context.evaluate(@template_name_expr)
       raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name

lib/liquid/template.rb

@@ -92,6 +92,14 @@ module Liquid
         @tags ||= TagRegistry.new
       end
 
+      def register_register(name, klass)
+        registers[name.to_s] = klass
+      end
+
+      def registers
+        @registers ||= {}
+      end
+
       def error_mode
         @error_mode ||= :lax
       end
@@ -203,6 +211,8 @@ module Liquid
         context.add_filters(args.pop)
       end
 
+      registers.merge!(Template.registers) if Template.registers.is_a?(Hash)
+
       # Retrying a render resets resource usage
       context.resource_limits.reset