Store filter names as symbols internally

lib/liquid/strainer_template.rb

@@ -24,11 +24,11 @@ module Liquid
 
         include(filter)
 
-        filter_methods.merge(filter.public_instance_methods.map(&:to_s))
+        filter_methods.merge(filter.public_instance_methods)
       end
 
       def invokable?(method)
-        filter_methods.include?(method.to_s)
+        filter_methods.include?(method.to_sym)
       end
 
       def inherited(subclass)
@@ -36,6 +36,9 @@ module Liquid
         subclass.instance_variable_set(:@filter_methods, @filter_methods.dup)
       end
 
+      # Assuming the filter name is a string is deprecated, explicitly
+      # cast to_s or to_sym for compatibility with liquid 6, where it is
+      # planned to return as a symbol.
       def filter_method_names
         filter_methods.map(&:to_s).to_a
       end
@@ -48,6 +51,7 @@ module Liquid
     end
 
     def invoke(method, *args)
+      method = method.to_sym
       if self.class.invokable?(method)
         send(method, *args)
       elsif @context.strict_filters

lib/liquid/variable.rb

@@ -18,7 +18,7 @@ module Liquid
     JustTagAttributes        = /\A#{TagAttributes}\z/o
     MarkupWithQuotedFragment = /(#{QuotedFragment})(.*)/om
 
-    attr_accessor :filters, :name, :line_number
+    attr_accessor :name, :line_number
     attr_reader :parse_context
     alias_method :options, :parse_context
 
@@ -52,7 +52,7 @@ module Liquid
         filters = Regexp.last_match(1).scan(FilterParser)
         filters.each do |f|
           next unless f =~ /\w+/
-          filtername = Regexp.last_match(0)
+          filtername = Regexp.last_match(0).to_sym
           filterargs = f.scan(FilterArgsRegex).flatten
           @filters << parse_filter_expressions(filtername, filterargs)
         end
@@ -67,13 +67,21 @@ module Liquid
 
       @name = parse_context.parse_expression(p.expression)
       while p.consume?(:pipe)
-        filtername = p.consume(:id)
+        filtername = p.consume(:id).to_sym
         filterargs = p.consume?(:colon) ? parse_filterargs(p) : []
         @filters << parse_filter_expressions(filtername, filterargs)
       end
       p.consume(:end_of_string)
     end
 
+    # Assuming the filter name is a string is deprecated, explicitly
+    # cast to_s or to_sym for compatibility with liquid 6, where it is
+    # planned to return as a symbol.
+    def filters
+      # Remove to_s in liquid 6.0
+      @filters.map { |key, *args| [key.to_s, *args].freeze }.freeze
+    end
+
     def parse_filterargs(p)
       # first argument
       filterargs = [p.argument]

test/unit/strainer_template_unit_test.rb

@@ -60,7 +60,7 @@ class StrainerTemplateUnitTest < Minitest::Test
     with_global_filter do
       strainer = Context.new.strainer
       strainer.class.add_filter(PublicMethodOverrideFilter)
-      assert(strainer.class.send(:filter_methods).include?('public_filter'))
+      assert(strainer.class.filter_method_names.include?('public_filter'))
     end
   end