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/block_body.rb

@@ -109,14 +109,22 @@ module Liquid
       end
     end
 
-    private def parse_for_document(tokenizer, parse_context)
+    private def handle_invalid_tag_token(token, parse_context)
+      if token.end_with?('%}')
+        yield token, token
+      else
+        BlockBody.raise_missing_tag_terminator(token, parse_context)
+      end
+    end
+
+    private def parse_for_document(tokenizer, parse_context, &block)
       while (token = tokenizer.shift)
         next if token.empty?
         case
         when token.start_with?(TAGSTART)
           whitespace_handler(token, parse_context)
           unless token =~ FullToken
-            BlockBody.raise_missing_tag_terminator(token, parse_context)
+            return handle_invalid_tag_token(token, parse_context, &block)
           end
           tag_name = Regexp.last_match(2)
           markup   = Regexp.last_match(4)

lib/liquid/forloop_drop.rb

@@ -5,7 +5,7 @@ module Liquid
   # @liquid_type object
   # @liquid_name forloop
   # @liquid_summary
-  #   Information about a parent [`for` loop](/api/liquid/tags#for).
+  #   Information about a parent [`for` loop](/api/liquid/tags/for).
   class ForloopDrop < Drop
     def initialize(name, length, parentloop)
       @name       = name
@@ -30,10 +30,7 @@ module Liquid
     # @liquid_return [forloop]
     attr_reader :parentloop
 
-    def name
-      Usage.increment('forloop_drop_name')
-      @name
-    end
+    attr_reader :name
 
     # @liquid_public_docs
     # @liquid_summary

lib/liquid/standardfilters.rb

@@ -6,7 +6,14 @@ require 'bigdecimal'
 
 module Liquid
   module StandardFilters
-    MAX_INT = (1 << 31) - 1
+    MAX_I32 = (1 << 31) - 1
+    private_constant :MAX_I32
+
+    MIN_I64 = -(1 << 63)
+    MAX_I64 = (1 << 63) - 1
+    I64_RANGE = MIN_I64..MAX_I64
+    private_constant :MIN_I64, :MAX_I64, :I64_RANGE
+
     HTML_ESCAPE = {
       '&' => '&amp;',
       '>' => '&gt;',
@@ -186,10 +193,19 @@ module Liquid
       offset = Utils.to_integer(offset)
       length = length ? Utils.to_integer(length) : 1
 
-      if input.is_a?(Array)
-        input.slice(offset, length) || []
-      else
-        input.to_s.slice(offset, length) || ''
+      begin
+        if input.is_a?(Array)
+          input.slice(offset, length) || []
+        else
+          input.to_s.slice(offset, length) || ''
+        end
+      rescue RangeError
+        if I64_RANGE.cover?(length) && I64_RANGE.cover?(offset)
+          raise # unexpected error
+        end
+        offset = offset.clamp(I64_RANGE)
+        length = length.clamp(I64_RANGE)
+        retry
       end
     end
 
@@ -239,9 +255,9 @@ module Liquid
       wordlist = begin
         input.split(" ", words + 1)
       rescue RangeError
-        raise if words + 1 < MAX_INT
-        # e.g. integer #{words} too big to convert to `int'
-        raise Liquid::ArgumentError, "integer #{words} too big for truncatewords"
+        # integer too big for String#split, but we can semantically assume no truncation is needed
+        return input if words + 1 > MAX_I32
+        raise # unexpected error
       end
       return input if wordlist.length <= words
 
@@ -599,7 +615,7 @@ module Liquid
     # @liquid_description
     #   > Note:
     #   > The `concat` filter won't filter out duplicates. If you want to remove duplicates, then you need to use the
-    #   > [`uniq` filter](/api/liquid/filters#uniq).
+    #   > [`uniq` filter](/api/liquid/filters/uniq).
     # @liquid_syntax array | concat: array
     # @liquid_return [array[untyped]]
     def concat(input, array)

lib/liquid/tablerowloop_drop.rb

@@ -5,7 +5,7 @@ module Liquid
   # @liquid_type object
   # @liquid_name tablerowloop
   # @liquid_summary
-  #   Information about a parent [`tablerow` loop](/api/liquid/tags#tablerow).
+  #   Information about a parent [`tablerow` loop](/api/liquid/tags/tablerow).
   class TablerowloopDrop < Drop
     def initialize(length, cols)
       @length = length

lib/liquid/tag.rb

@@ -14,12 +14,18 @@ module Liquid
       end
 
       def disable_tags(*tag_names)
-        @disabled_tags ||= []
-        @disabled_tags.concat(tag_names)
+        tag_names += disabled_tags
+        define_singleton_method(:disabled_tags) { tag_names }
         prepend(Disabler)
       end
 
       private :new
+
+      protected
+
+      def disabled_tags
+        []
+      end
     end
 
     def initialize(tag_name, markup, parse_context)

lib/liquid/tag/disabler.rb

@@ -3,14 +3,6 @@
 module Liquid
   class Tag
     module Disabler
-      module ClassMethods
-        attr_reader :disabled_tags
-      end
-
-      def self.prepended(base)
-        base.extend(ClassMethods)
-      end
-
       def render_to_output_buffer(context, output)
         context.with_disabled_tags(self.class.disabled_tags) do
           super

lib/liquid/tags/break.rb

@@ -15,7 +15,7 @@ module Liquid
   # @liquid_category iteration
   # @liquid_name break
   # @liquid_summary
-  #   Stops a [`for` loop](/api/liquid/tags#for) from iterating.
+  #   Stops a [`for` loop](/api/liquid/tags/for) from iterating.
   # @liquid_syntax
   #   {% break %}
   class Break < Tag

lib/liquid/tags/comment.rb

@@ -8,7 +8,7 @@ module Liquid
   # @liquid_summary
   #   Prevents an expression from being rendered or output.
   # @liquid_description
-  #   Any text inside `comment` tags won't be output, and any Liquid code won't be rendered.
+  #   Any text inside `comment` tags won't be output, and any Liquid code will be parsed, but not executed.
   # @liquid_syntax
   #   {% comment %}
   #     content

lib/liquid/tags/continue.rb

@@ -6,7 +6,7 @@ module Liquid
   # @liquid_category iteration
   # @liquid_name continue
   # @liquid_summary
-  #   Causes a [`for` loop](/api/liquid/tags#for) to skip to the next iteration.
+  #   Causes a [`for` loop](/api/liquid/tags/for) to skip to the next iteration.
   # @liquid_syntax
   #   {% continue %}
   class Continue < Tag

lib/liquid/tags/cycle.rb

@@ -6,7 +6,7 @@ module Liquid
   # @liquid_category iteration
   # @liquid_name cycle
   # @liquid_summary
-  #   Loops through a group of strings and outputs them one at a time for each iteration of a [`for` loop](/api/liquid/tags#for).
+  #   Loops through a group of strings and outputs them one at a time for each iteration of a [`for` loop](/api/liquid/tags/for).
   # @liquid_description
   #   The `cycle` tag must be used inside a `for` loop.
   #

lib/liquid/tags/decrement.rb

@@ -12,8 +12,8 @@ module Liquid
   #   or [section](/themes/architecture/sections) file that they're created in. However, the variable is shared across
   #   [snippets](/themes/architecture#snippets) included in the file.
   #
-  #   Similarly, variables that are created with `decrement` are independent from those created with [`assign`](/api/liquid/tags#assign)
-  #   and [`capture`](/api/liquid/tags#capture). However, `decrement` and [`increment`](/api/liquid/tags#increment) share
+  #   Similarly, variables that are created with `decrement` are independent from those created with [`assign`](/api/liquid/tags/assign)
+  #   and [`capture`](/api/liquid/tags/capture). However, `decrement` and [`increment`](/api/liquid/tags/increment) share
   #   variables.
   # @liquid_syntax
   #   {% decrement variable_name %}

lib/liquid/tags/echo.rb

@@ -9,7 +9,7 @@ module Liquid
   #   Outputs an expression.
   # @liquid_description
   #   Using the `echo` tag is the same as wrapping an expression in curly brackets (`{{` and `}}`). However, unlike the curly
-  #   bracket method, you can use the `echo` tag inside [`liquid` tags](/api/liquid/tags#liquid).
+  #   bracket method, you can use the `echo` tag inside [`liquid` tags](/api/liquid/tags/liquid).
   #
   #   > Tip:
   #   > You can use [filters](/api/liquid/filters) on expressions inside `echo` tags.

lib/liquid/tags/for.rb

@@ -9,10 +9,10 @@ module Liquid
   #   Renders an expression for every item in an array.
   # @liquid_description
   #   You can do a maximum of 50 iterations with a `for` loop. If you need to iterate over more than 50 items, then use the
-  #   [`paginate` tag](/api/liquid/tags#paginate) to split the items over multiple pages.
+  #   [`paginate` tag](/api/liquid/tags/paginate) to split the items over multiple pages.
   #
   #   > Tip:
-  #   > Every `for` loop has an associated [`forloop` object](/api/liquid/objects#forloop) with information about the loop.
+  #   > Every `for` loop has an associated [`forloop` object](/api/liquid/objects/forloop) with information about the loop.
   # @liquid_syntax
   #   {% for variable in array %}
   #     expression
@@ -177,7 +177,6 @@ module Liquid
       case key
       when 'offset'
         @from = if expr == 'continue'
-          Usage.increment('for_offset_continue')
           :continue
         else
           parse_expression(expr)

lib/liquid/tags/include.rb

@@ -8,7 +8,7 @@ module Liquid
   # @liquid_summary
   #   Renders a [snippet](/themes/architecture#snippets).
   # @liquid_description
-  #   Inside the snippet, you can access and alter variables that are [created](/api/liquid/tags#variable-tags) outside of the
+  #   Inside the snippet, you can access and alter variables that are [created](/api/liquid/tags/variable-tags) outside of the
   #   snippet.
   # @liquid_syntax
   #   {% include 'filename' %}
@@ -16,7 +16,7 @@ module Liquid
   # @liquid_deprecated
   #   Deprecated because the way that variables are handled reduces performance and makes code harder to both read and maintain.
   #
-  #   The `include` tag has been replaced by [`render`](/api/liquid/tags#render).
+  #   The `include` tag has been replaced by [`render`](/api/liquid/tags/render).
   class Include < Tag
     prepend Tag::Disableable
 
@@ -52,7 +52,7 @@ module Liquid
 
     def render_to_output_buffer(context, output)
       template_name = context.evaluate(@template_name_expr)
-      raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name
+      raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name.is_a?(String)
 
       partial = PartialCache.load(
         template_name,

lib/liquid/tags/increment.rb

@@ -12,8 +12,8 @@ module Liquid
   #   or [section](/themes/architecture/sections) file that they're created in. However, the variable is shared across
   #   [snippets](/themes/architecture#snippets) included in the file.
   #
-  #   Similarly, variables that are created with `increment` are independent from those created with [`assign`](/api/liquid/tags#assign)
-  #   and [`capture`](/api/liquid/tags#capture). However, `increment` and [`decrement`](/api/liquid/tags#decrement) share
+  #   Similarly, variables that are created with `increment` are independent from those created with [`assign`](/api/liquid/tags/assign)
+  #   and [`capture`](/api/liquid/tags/capture). However, `increment` and [`decrement`](/api/liquid/tags/decrement) share
   #   variables.
   # @liquid_syntax
   #   {% increment variable_name %}

lib/liquid/tags/render.rb

@@ -8,19 +8,19 @@ module Liquid
   # @liquid_summary
   #   Renders a [snippet](/themes/architecture#snippets) or [app block](/themes/architecture/sections/section-schema#render-app-blocks).
   # @liquid_description
-  #   Inside snippets and app blocks, you can't directly access variables that are [created](/api/liquid/tags#variable-tags) outside
-  #   of the snippet or app block. However, you can [specify variables as parameters](/api/liquid/tags#render-passing-variables-to-snippets)
+  #   Inside snippets and app blocks, you can't directly access variables that are [created](/api/liquid/tags/variable-tags) outside
+  #   of the snippet or app block. However, you can [specify variables as parameters](/api/liquid/tags/render#render-passing-variables-to-a-snippet)
   #   to pass outside variables to snippets.
   #
   #   While you can't directly access created variables, you can access global objects, as well as any objects that are
   #   directly accessible outside the snippet or app block. For example, a snippet or app block inside the [product template](/themes/architecture/templates/product)
-  #   can access the [`product` object](/api/liquid/objects#product), and a snippet or app block inside a [section](/themes/architecture/sections)
-  #   can access the [`section` object](/api/liquid/objects#section).
+  #   can access the [`product` object](/api/liquid/objects/product), and a snippet or app block inside a [section](/themes/architecture/sections)
+  #   can access the [`section` object](/api/liquid/objects/section).
   #
   #   Outside a snippet or app block, you can't access variables created inside the snippet or app block.
   #
   #   > Note:
-  #   > When you render a snippet using the `render` tag, you can't use the [`include` tag](/api/liquid/tags#include)
+  #   > When you render a snippet using the `render` tag, you can't use the [`include` tag](/api/liquid/tags/include)
   #   > inside the snippet.
   # @liquid_syntax
   #   {% render 'filename' %}

lib/liquid/tags/table_row.rb

@@ -11,7 +11,7 @@ module Liquid
   #   The `tablerow` tag must be wrapped in HTML `<table>` and `</table>` tags.
   #
   #   > Tip:
-  #   > Every `tablerow` loop has an associated [`tablerowloop` object](/api/liquid/objects#tablerowloop) with information about the loop.
+  #   > Every `tablerow` loop has an associated [`tablerowloop` object](/api/liquid/objects/tablerowloop) with information about the loop.
   # @liquid_syntax
   #   {% tablerow variable in array %}
   #     expression
@@ -51,7 +51,7 @@ module Liquid
       collection = Utils.slice_collection(collection, from, to)
       length     = collection.length
 
-      cols = context.evaluate(@attributes['cols']).to_i
+      cols = @attributes.key?('cols') ? context.evaluate(@attributes['cols']).to_i : length
 
       output << "<tr class=\"row1\">\n"
       context.stack do

lib/liquid/tags/unless.rb

@@ -11,7 +11,7 @@ module Liquid
   #   Renders an expression unless a specific condition is `true`.
   # @liquid_description
   #   > Tip:
-  #   > Similar to the [`if` tag](/api/liquid/tags#if), you can use `elsif` to add more conditions to an `unless` tag.
+  #   > Similar to the [`if` tag](/api/liquid/tags/if), you can use `elsif` to add more conditions to an `unless` tag.
   # @liquid_syntax
   #   {% unless condition %}
   #     expression

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/standard_filter_test.rb

@@ -109,6 +109,10 @@ class StandardFiltersTest < Minitest::Test
     assert_raises(Liquid::ArgumentError) do
       @filters.slice('foobar', 0, "")
     end
+    assert_equal("", @filters.slice("foobar", 0, -(1 << 64)))
+    assert_equal("foobar", @filters.slice("foobar", 0, 1 << 63))
+    assert_equal("", @filters.slice("foobar", 1 << 63, 6))
+    assert_equal("", @filters.slice("foobar", -(1 << 63), 6))
   end
 
   def test_slice_on_arrays
@@ -123,6 +127,10 @@ class StandardFiltersTest < Minitest::Test
     assert_equal(%w(r), @filters.slice(input, -1))
     assert_equal(%w(), @filters.slice(input, 100, 10))
     assert_equal(%w(), @filters.slice(input, -100, 10))
+    assert_equal([], @filters.slice(input, 0, -(1 << 64)))
+    assert_equal(input, @filters.slice(input, 0, 1 << 63))
+    assert_equal([], @filters.slice(input, 1 << 63, 6))
+    assert_equal([], @filters.slice(input, -(1 << 63), 6))
   end
 
   def test_truncate
@@ -132,6 +140,8 @@ class StandardFiltersTest < Minitest::Test
     assert_equal('1234567890', @filters.truncate('1234567890'))
     assert_equal("测试...", @filters.truncate("测试测试测试测试", 5))
     assert_equal('12341', @filters.truncate("1234567890", 5, 1))
+    assert_equal("foobar", @filters.truncate("foobar", 1 << 63))
+    assert_equal("...", @filters.truncate("foobar", -(1 << 63)))
   end
 
   def test_split
@@ -227,10 +237,8 @@ class StandardFiltersTest < Minitest::Test
     assert_equal('one two three...', @filters.truncatewords("one  two\tthree\nfour", 3))
     assert_equal('one two...', @filters.truncatewords("one two three four", 2))
     assert_equal('one...', @filters.truncatewords("one two three four", 0))
-    exception = assert_raises(Liquid::ArgumentError) do
-      @filters.truncatewords("one two three four", 1 << 31)
-    end
-    assert_equal("Liquid error: integer #{1 << 31} too big for truncatewords", exception.message)
+    assert_equal('one two three four', @filters.truncatewords("one two three four", 1 << 31))
+    assert_equal('one...', @filters.truncatewords("one two three four", -(1 << 32)))
   end
 
   def test_strip_html

test/integration/tags/for_tag_test.rb

@@ -450,30 +450,4 @@ HERE
 
     assert(context.registers[:for_stack].empty?)
   end
-
-  def test_instrument_for_offset_continue
-    assert_usage_increment('for_offset_continue') do
-      Template.parse('{% for item in items offset:continue %}{{item}}{% endfor %}')
-    end
-
-    assert_usage_increment('for_offset_continue', times: 0) do
-      Template.parse('{% for item in items offset:2 %}{{item}}{% endfor %}')
-    end
-  end
-
-  def test_instrument_forloop_drop_name
-    assigns = { 'items' => [1, 2, 3, 4, 5] }
-
-    assert_usage_increment('forloop_drop_name', times: 5) do
-      Template.parse('{% for item in items %}{{forloop.name}}{% endfor %}').render!(assigns)
-    end
-
-    assert_usage_increment('forloop_drop_name', times: 0) do
-      Template.parse('{% for item in items %}{{forloop.index}}{% endfor %}').render!(assigns)
-    end
-
-    assert_usage_increment('forloop_drop_name', times: 0) do
-      Template.parse('{% for item in items %}{{item}}{% endfor %}').render!(assigns)
-    end
-  end
 end

test/integration/tags/include_tag_test.rb

@@ -249,6 +249,11 @@ class IncludeTagTest < Minitest::Test
       "{% include nil %}", render_errors: true)
   end
 
+  def test_render_raise_argument_error_when_template_is_not_a_string
+    assert_template_result("Liquid error (line 1): Argument error in tag 'include' - Illegal template name",
+      "{% include 123 %}", render_errors: true)
+  end
+
   def test_including_via_variable_value
     assert_template_result("from TestFileSystem", "{% assign page = 'pick_a_source' %}{% include page %}",
       partials: { "pick_a_source" => "from TestFileSystem" })

test/integration/tags/standard_tag_test.rb

@@ -36,6 +36,8 @@ class StandardTagTest < Minitest::Test
     assert_template_result('', '{%comment%}{% endif %}{%endcomment%}')
     assert_template_result('', '{% comment %}{% endwhatever %}{% endcomment %}')
     assert_template_result('', '{% comment %}{% raw %} {{%%%%}}  }} { {% endcomment %} {% comment {% endraw %} {% endcomment %}')
+    assert_template_result('', '{% comment %}{% " %}{% endcomment %}')
+    assert_template_result('', '{% comment %}{%%}{% endcomment %}')
 
     assert_template_result('foobar', 'foo{%comment%}comment{%endcomment%}bar')
     assert_template_result('foobar', 'foo{% comment %}comment{% endcomment %}bar')

test/integration/tags/table_row_test.rb

@@ -65,4 +65,70 @@ class TableRowTest < Minitest::Test
       "{% tablerow char in characters cols:3 %}I WILL NOT BE OUTPUT{% endtablerow %}",
       { 'characters' => '' })
   end
+
+  def test_cols_nil_constant_same_as_evaluated_nil_expression
+    expect = "<tr class=\"row1\">\n" \
+      "<td class=\"col1\">false</td>" \
+      "<td class=\"col2\">false</td>" \
+      "</tr>\n"
+
+    assert_template_result(expect,
+      "{% tablerow i in (1..2) cols:nil %}{{ tablerowloop.col_last }}{% endtablerow %}")
+
+    assert_template_result(expect,
+      "{% tablerow i in (1..2) cols:var %}{{ tablerowloop.col_last }}{% endtablerow %}",
+      { "var" => nil })
+  end
+
+  def test_tablerow_loop_drop_attributes
+    template = <<~LIQUID.chomp
+      {% tablerow i in (1...2) %}
+      col: {{ tablerowloop.col }}
+      col0: {{ tablerowloop.col0 }}
+      col_first: {{ tablerowloop.col_first }}
+      col_last: {{ tablerowloop.col_last }}
+      first: {{ tablerowloop.first }}
+      index: {{ tablerowloop.index }}
+      index0: {{ tablerowloop.index0 }}
+      last: {{ tablerowloop.last }}
+      length: {{ tablerowloop.length }}
+      rindex: {{ tablerowloop.rindex }}
+      rindex0: {{ tablerowloop.rindex0 }}
+      row: {{ tablerowloop.row }}
+      {% endtablerow %}
+    LIQUID
+
+    expected_output = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">
+      col: 1
+      col0: 0
+      col_first: true
+      col_last: false
+      first: true
+      index: 1
+      index0: 0
+      last: false
+      length: 2
+      rindex: 2
+      rindex0: 1
+      row: 1
+      </td><td class="col2">
+      col: 2
+      col0: 1
+      col_first: false
+      col_last: true
+      first: false
+      index: 2
+      index0: 1
+      last: true
+      length: 2
+      rindex: 1
+      rindex0: 0
+      row: 1
+      </td></tr>
+    OUTPUT
+
+    assert_template_result(expected_output, template)
+  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

@@ -42,7 +42,7 @@ module Minitest
       message: nil, partials: nil, error_mode: nil, render_errors: false
     )
       template = Liquid::Template.parse(template, line_numbers: true, error_mode: error_mode&.to_sym)
-      file_system = StubFileSystem.new(partials) if partials
+      file_system = StubFileSystem.new(partials || {})
       registers = Liquid::Registers.new(file_system: file_system)
       context = Liquid::Context.build(environments: assigns, rethrow_errors: !render_errors, registers: registers)
       output = template.render(context)