Add ParseTreeVisitor to Echo tag

This fixes theme-check#218, wherein variables used in echo tags are not
considered used by the linter. It is because our visitor doesn't see the
:variable_lookup's in the echo tag since the children array is empty.
But this array is empty because it is swallowed by the @variable.

.github/workflows/liquid.yml

@@ -6,9 +6,8 @@ jobs:
     strategy:
       matrix:
         entry:
-          - { ruby: 2.5, allowed-failure: false }
+          - { ruby: 2.5, allowed-failure: false } # minimum supported
-          - { ruby: 2.6, allowed-failure: false }
+          - { ruby: 3.0, allowed-failure: false } # latest
-          - { ruby: 2.7, allowed-failure: false }
           - { ruby: ruby-head, allowed-failure: true }
     name: test (${{ matrix.entry.ruby }})
     steps:

.rubocop.yml

@@ -1,5 +1,7 @@
+inherit_gem:
+  rubocop-shopify: rubocop.yml
+
 inherit_from:
-  - 'https://shopify.github.io/ruby-style-guide/rubocop.yml'
   - .rubocop_todo.yml
 
 require: rubocop-performance

CONTRIBUTING.md

@@ -5,6 +5,7 @@
 * Bugfixes
 * Performance improvements
 * Features that are likely to be useful to the majority of Liquid users
+* Documentation updates that are concise and likely to be useful to the majority of Liquid users
 
 ## Things we won't merge
 
@@ -14,12 +15,14 @@
 * Features that can easily be implemented on top of Liquid (for example as a custom filter or custom filesystem)
 * Code that does not include tests
 * Code that breaks existing tests
+* Documentation changes that are verbose, incorrect or not important to most people (we want to keep it simple and easy to understand)
 
 ## Workflow
 
+* [Sign the CLA](https://cla.shopify.com/) if you haven't already
 * Fork the Liquid repository
 * Create a new branch in your fork
+  * For updating [Liquid documentation](https://shopify.github.io/liquid/), create it from `gh-pages` branch. (You can skip tests.)
 * If it makes sense, add tests for your code and/or run a performance benchmark
 * Make sure all tests pass (`bundle exec rake`)
 * Create a pull request
-

Gemfile

@@ -19,6 +19,7 @@ end
 
 group :test do
   gem 'rubocop', '~> 1.4', require: false
+  gem 'rubocop-shopify', '~> 1.0.7', require: false
   gem 'rubocop-performance', require: false
 
   platform :mri, :truffleruby do

lib/liquid/standardfilters.rb

@@ -89,13 +89,15 @@ module Liquid
 
     def truncatewords(input, words = 15, truncate_string = "...")
       return if input.nil?
-      wordlist = input.to_s.split
+      input = input.to_s
-      words    = Utils.to_integer(words)
+      words = Utils.to_integer(words)
+      words = 1 if words <= 0
 
-      l = words - 1
+      wordlist = input.split(" ", words + 1)
-      l = 0 if l < 0
+      return input if wordlist.length <= words
 
-      wordlist.length > l ? wordlist[0..l].join(" ").concat(truncate_string.to_s) : input
+      wordlist.pop
+      wordlist.join(" ").concat(truncate_string.to_s)
     end
 
     # Split input string into an array of substrings separated by given pattern.
@@ -295,7 +297,7 @@ module Liquid
 
     # Add <br /> tags in front of all newlines in input string
     def newline_to_br(input)
-      input.to_s.gsub(/\n/, "<br />\n")
+      input.to_s.gsub(/\r?\n/, "<br />\n")
     end
 
     # Reformat a date using Ruby's core Time#strftime( string ) -> string

lib/liquid/tags/echo.rb

@@ -12,6 +12,8 @@ module Liquid
   #   {% echo user | link %}
   #
   class Echo < Tag
+    attr_reader :variable
+
     def initialize(tag_name, markup, parse_context)
       super
       @variable = Variable.new(markup, parse_context)
@@ -20,6 +22,12 @@ module Liquid
     def render(context)
       @variable.render_to_output_buffer(context, +'')
     end
+
+    class ParseTreeVisitor < Liquid::ParseTreeVisitor
+      def children
+        [@node.variable]
+      end
+    end
   end
 
   Template.register_tag('echo', Echo)

test/integration/context_test.rb

@@ -461,6 +461,7 @@ class ContextTest < Minitest::Test
   end
 
   def test_interrupt_avoids_object_allocations
+    @context.interrupt? # ruby 3.0.0 allocates on the first call
     assert_no_object_allocations do
       @context.interrupt?
     end

test/integration/standard_filter_test.rb

@@ -171,10 +171,13 @@ class StandardFiltersTest < Minitest::Test
     assert_equal('one two three', @filters.truncatewords('one two three'))
     assert_equal(
       'Two small (13&#8221; x 5.5&#8221; x 10&#8221; high) baskets fit inside one large basket (13&#8221;...',
-        @filters.truncatewords('Two small (13&#8221; x 5.5&#8221; x 10&#8221; high) baskets fit inside one large basket (13&#8221; x 16&#8221; x 10.5&#8221; high) with cover.', 15)
+      @filters.truncatewords('Two small (13&#8221; x 5.5&#8221; x 10&#8221; high) baskets fit inside one large basket (13&#8221; x 16&#8221; x 10.5&#8221; high) with cover.', 15)
     )
     assert_equal("测试测试测试测试", @filters.truncatewords('测试测试测试测试', 5))
     assert_equal('one two1', @filters.truncatewords("one two three", 2, 1))
+    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))
   end
 
   def test_strip_html
@@ -539,6 +542,7 @@ class StandardFiltersTest < Minitest::Test
 
   def test_newlines_to_br
     assert_template_result("a<br />\nb<br />\nc", "{{ source | newline_to_br }}", 'source' => "a\nb\nc")
+    assert_template_result("a<br />\nb<br />\nc", "{{ source | newline_to_br }}", 'source' => "a\r\nb\nc")
   end
 
   def test_plus

test/integration/tags/include_tag_test.rb

@@ -96,12 +96,12 @@ class IncludeTagTest < Minitest::Test
 
   def test_include_tag_with_alias
     assert_template_result("Product: Draft 151cm ",
-                           "{% include 'product_alias' with products[0] as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% include 'product_alias' with products[0] as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_include_tag_for_alias
     assert_template_result("Product: Draft 151cm Product: Element 155cm ",
-                           "{% include 'product_alias' for products as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% include 'product_alias' for products as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_include_tag_with_default_name

test/integration/tags/render_tag_test.rb

@@ -151,7 +151,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm ",
-                           "{% render 'product' with products[0] %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product' with products[0] %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_with_alias
@@ -161,7 +161,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm ",
-                           "{% render 'product_alias' with products[0] as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product_alias' with products[0] as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_for_alias
@@ -171,7 +171,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm Product: Element 155cm ",
-                           "{% render 'product_alias' for products as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product_alias' for products as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_for
@@ -181,7 +181,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm Product: Element 155cm ",
-                           "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_forloop
@@ -190,7 +190,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm first  index:1 Product: Element 155cm  last index:2 ",
-                           "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_for_drop
@@ -199,7 +199,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("123",
-                           "{% render 'loop' for loop as value %}", "loop" => TestEnumerable.new)
+      "{% render 'loop' for loop as value %}", "loop" => TestEnumerable.new)
   end
 
   def test_render_tag_with_drop
@@ -208,6 +208,6 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("TestEnumerable",
-                           "{% render 'loop' with loop as value %}", "loop" => TestEnumerable.new)
+      "{% render 'loop' with loop as value %}", "loop" => TestEnumerable.new)
   end
 end

test/unit/parse_tree_visitor_test.rb

@@ -26,6 +26,13 @@ class ParseTreeVisitorTest < Minitest::Test
     )
   end
 
+  def test_echo
+    assert_equal(
+      ["test"],
+      visit(%({% echo test %}))
+    )
+  end
+
   def test_if_condition
     assert_equal(
       ["test"],