Special case Hash#last in variable lookup

Ruby's defines Hash#first via Enumerable but not Hash#last.
This is a confusing behaviour, and it bubbles up to Liquid.

Solution: add a special case for command-lookups of Hash#last to return
hash.values.last.

lib/liquid/tags/inline_comment.rb

@@ -1,6 +1,19 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name inline_comment
+  # @liquid_summary
+  #   Prevents an expression from being rendered or output.
+  # @liquid_description
+  #   Any text inside an `inline_comment` tag won't be rendered or output.
+  #
+  #   You can create multi-line inline comments. However, each line must begin with a `#`.
+  # @liquid_syntax
+  #   {% # content %}
+  # @liquid_syntax_keyword content The content of the comment.
   class InlineComment < Tag
     def initialize(tag_name, markup, options)
       super

lib/liquid/tokenizer.rb

@@ -8,15 +8,11 @@ module Liquid
       @source         = source.to_s.to_str
       @line_number    = line_number || (line_numbers ? 1 : nil)
       @for_liquid_tag = for_liquid_tag
-      @offset         = 0
       @tokens         = tokenize
     end
 
     def shift
-      token = @tokens[@offset]
-      return nil unless token
-
-      @offset += 1
+      (token = @tokens.shift) || return
 
       if @line_number
         @line_number += @for_liquid_tag ? 1 : token.count("\n")
@@ -35,9 +31,7 @@ module Liquid
       tokens = @source.split(TemplateParser)
 
       # removes the rogue empty element at the beginning of the array
-      if tokens[0]&.empty?
-        @offset += 1
-      end
+      tokens.shift if tokens[0]&.empty?
 
       tokens
     end

lib/liquid/variable_lookup.rb

@@ -61,11 +61,15 @@ module Liquid
           # as commands and call them on the current object
         elsif lookup_command?(i) && object.respond_to?(key)
           object = object.send(key).to_liquid
+        elsif lookup_command?(i) && object.is_a?(Hash) && key == 'last'
+          # Ruby defines Hash#first via Enumerable but not Hash#last.
+          # This is unexpected, so we explicitly handle that case here.
+          object = object.values.last.to_liquid
+        else
 
           # No key was present with the desired value and it wasn't one of the directly supported
           # keywords either. The only thing we got left is to return nil or
           # raise an exception if `strict_variables` option is set to true
-        else
           return nil unless context.strict_variables
           raise Liquid::UndefinedVariable, "undefined variable #{key}"
         end

test/integration/tags/increment_tag_test.rb

@@ -6,21 +6,20 @@ class IncrementTagTest < Minitest::Test
   include Liquid
 
   def test_inc
-    assert_template_result('0 1', '{%increment port %} {{ port }}')
-    assert_template_result(' 0 1 2', '{{port}} {%increment port %} {%increment port%} {{port}}')
+    assert_template_result('0', '{%increment port %}', {})
+    assert_template_result('0 1', '{%increment port %} {%increment port%}', {})
     assert_template_result('0 0 1 2 1',
       '{%increment port %} {%increment starboard%} ' \
       '{%increment port %} {%increment port%} ' \
-      '{%increment starboard %}')
+      '{%increment starboard %}', {})
   end
 
   def test_dec
-    assert_template_result('-1 -1', '{%decrement port %} {{ port }}', { 'port' => 10 })
-    assert_template_result(' -1 -2 -2', '{{port}} {%decrement port %} {%decrement port%} {{port}}')
-    assert_template_result('0 1 2 0 3 1 1 3',
-      '{%increment starboard %} {%increment starboard%} {%increment starboard%} ' \
+    assert_template_result('9', '{%decrement port %}', { 'port' => 10 })
+    assert_template_result('-1 -2', '{%decrement port %} {%decrement port%}', {})
+    assert_template_result('1 5 2 2 5',
       '{%increment port %} {%increment starboard%} ' \
       '{%increment port %} {%decrement port%} ' \
-      '{%decrement starboard %}')
+      '{%decrement starboard %}', { 'port' => 1, 'starboard' => 5 })
   end
 end

test/integration/variable_test.rb

@@ -130,4 +130,8 @@ class VariableTest < Minitest::Test
   def test_raw_value_variable
     assert_template_result('bar', '{{ [key] }}', { 'key' => 'foo', 'foo' => 'bar' })
   end
+
+  def test_hash_last
+    assert_template_result('last', '{{ hash.last }}', { 'hash' => { 'first' => 'first', 'last' => 'last' } })
+  end
 end

test/test_helper.rb

@@ -44,7 +44,7 @@ module Minitest
       template = Liquid::Template.parse(template, line_numbers: true, error_mode: error_mode&.to_sym)
       file_system = StubFileSystem.new(partials || {})
       registers = Liquid::Registers.new(file_system: file_system)
-      context = Liquid::Context.build(static_environments: assigns, rethrow_errors: !render_errors, registers: registers)
+      context = Liquid::Context.build(environments: assigns, rethrow_errors: !render_errors, registers: registers)
       output = template.render(context)
       assert_equal(expected, output, message)
     end