document default filter

lib/liquid/standardfilters.rb

@@ -421,13 +421,20 @@ module Liquid
       result.is_a?(BigDecimal) ? result.to_f : result
     end
 
-    def default(input, default_value = '')
-      if !input || input.respond_to?(:empty?) && input.empty?
-        Usage.increment("default_filter_received_false_value") if input == false # See https://github.com/Shopify/liquid/issues/1127
-        default_value
-      else
-        input
-      end
+    # Set a default value when the input is nil, false or empty
+    #
+    # Example:
+    #    {{ product.title | default: "No Title" }}
+    #
+    # Use `allow_false` when an input should only be tested against nil or empty and not false.
+    #
+    # Example:
+    #    {{ product.title | default: "No Title", allow_false: true }}
+    #
+    def default(input, default_value = '', options = {})
+      options = {} unless options.is_a?(Hash)
+      false_check = options['allow_false'] ? input.nil? : !input
+      false_check || (input.respond_to?(:empty?) && input.empty?) ? default_value : input
     end
 
     private

lib/liquid/tags/include.rb

@@ -16,20 +16,18 @@ module Liquid
   #   {% include 'product' for products %}
   #
   class Include < Tag
-    SYNTAX = /(#{QuotedFragment}+)(\s+(?:with|for)\s+(#{QuotedFragment}+))?(\s+(?:as)\s+(#{VariableSegment}+))?/o
-    Syntax = SYNTAX
+    Syntax = /(#{QuotedFragment}+)(\s+(?:with|for)\s+(#{QuotedFragment}+))?/o
 
     attr_reader :template_name_expr, :variable_name_expr, :attributes
 
     def initialize(tag_name, markup, options)
       super
 
-      if markup =~ SYNTAX
+      if markup =~ Syntax
 
         template_name = Regexp.last_match(1)
         variable_name = Regexp.last_match(3)
 
-        @alias_name = Regexp.last_match(5)
         @variable_name_expr = variable_name ? Expression.parse(variable_name) : nil
         @template_name_expr = Expression.parse(template_name)
         @attributes = {}
@@ -56,7 +54,7 @@ module Liquid
         parse_context: parse_context
       )
 
-      context_variable_name = @alias_name || template_name.split('/').last
+      context_variable_name = template_name.split('/').last
 
       variable = if @variable_name_expr
         context.evaluate(@variable_name_expr)

lib/liquid/tags/render.rb

@@ -2,7 +2,7 @@
 
 module Liquid
   class Render < Tag
-    SYNTAX = /(#{QuotedString}+)(\s+(?:with|for)\s+(#{QuotedFragment}+))?(\s+(?:as)\s+(#{VariableSegment}+))?/o
+    SYNTAX = /(#{QuotedString})#{QuotedFragment}*/o
 
     disable_tags "include"
 
@@ -14,10 +14,7 @@ module Liquid
       raise SyntaxError, options[:locale].t("errors.syntax.render") unless markup =~ SYNTAX
 
       template_name = Regexp.last_match(1)
-      variable_name = Regexp.last_match(3)
 
-      @alias_name = Regexp.last_match(5)
-      @variable_name_expr = variable_name ? Expression.parse(variable_name) : nil
       @template_name_expr = Expression.parse(template_name)
 
       @attributes = {}
@@ -41,21 +38,13 @@ module Liquid
         parse_context: parse_context
       )
 
-      context_variable_name = @alias_name || template_name.split('/').last
-
-      render_partial_func = ->(var) {
-        inner_context = context.new_isolated_subcontext
-        inner_context.template_name = template_name
-        inner_context.partial = true
-        @attributes.each do |key, value|
-          inner_context[key] = context.evaluate(value)
-        end
-        inner_context[context_variable_name] = var unless var.nil?
-        partial.render_to_output_buffer(inner_context, output)
-      }
-
-      variable = @variable_name_expr ? context.evaluate(@variable_name_expr) : nil
-      variable.is_a?(Array) ? variable.each(&render_partial_func) : render_partial_func.call(variable)
+      inner_context = context.new_isolated_subcontext
+      inner_context.template_name = template_name
+      inner_context.partial = true
+      @attributes.each do |key, value|
+        inner_context[key] = context.evaluate(value)
+      end
+      partial.render_to_output_buffer(inner_context, output)
 
       output
     end

test/integration/standard_filter_test.rb

@@ -685,6 +685,17 @@ class StandardFiltersTest < Minitest::Test
     assert_equal("bar", @filters.default(false, "bar"))
     assert_equal("bar", @filters.default([], "bar"))
     assert_equal("bar", @filters.default({}, "bar"))
+    assert_template_result('bar', "{{ false | default: 'bar' }}")
+  end
+
+  def test_default_handle_false
+    assert_equal("foo", @filters.default("foo", "bar", "allow_false" => true))
+    assert_equal("bar", @filters.default(nil, "bar", "allow_false" => true))
+    assert_equal("bar", @filters.default("", "bar", "allow_false" => true))
+    assert_equal(false, @filters.default(false, "bar", "allow_false" => true))
+    assert_equal("bar", @filters.default([], "bar", "allow_false" => true))
+    assert_equal("bar", @filters.default({}, "bar", "allow_false" => true))
+    assert_template_result('false', "{{ false | default: 'bar', allow_false: true }}")
   end
 
   def test_cannot_access_private_methods

test/integration/tags/include_tag_test.rb

@@ -8,9 +8,6 @@ class TestFileSystem
     when "product"
       "Product: {{ product.title }} "
 
-    when "product_alias"
-      "Product: {{ product.title }} "
-
     when "locale_variables"
       "Locale: {{echo1}} {{echo2}}"
 
@@ -94,16 +91,6 @@ class IncludeTagTest < Minitest::Test
       "{% include 'product' with products[0] %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
-  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' }])
-  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' }])
-  end
-
   def test_include_tag_with_default_name
     assert_template_result("Product: Draft 151cm ",
       "{% include 'product' %}", "product" => { 'title' => 'Draft 151cm' })

test/integration/tags/render_tag_test.rb

@@ -165,44 +165,4 @@ class RenderTagTest < Minitest::Test
 
     assert_template_result('include usage is not allowed in this contextinclude usage is not allowed in this context', '{% render "nested_render_with_sibling_include" %}')
   end
-
-  def test_render_tag_with
-    Liquid::Template.file_system = StubFileSystem.new(
-      'product' => "Product: {{ product.title }} ",
-      'product_alias' => "Product: {{ product.title }} ",
-    )
-
-    assert_template_result("Product: Draft 151cm ",
-                           "{% render 'product' with products[0] %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
-  end
-
-  def test_render_tag_with_alias
-    Liquid::Template.file_system = StubFileSystem.new(
-      'product' => "Product: {{ product.title }} ",
-      'product_alias' => "Product: {{ product.title }} ",
-    )
-
-    assert_template_result("Product: Draft 151cm ",
-                           "{% render 'product_alias' with products[0] as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
-  end
-
-  def test_render_tag_for_alias
-    Liquid::Template.file_system = StubFileSystem.new(
-      'product' => "Product: {{ product.title }} ",
-      'product_alias' => "Product: {{ product.title }} ",
-    )
-
-    assert_template_result("Product: Draft 151cm Product: Element 155cm ",
-                           "{% render 'product_alias' for products as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
-  end
-
-  def test_render_tag_for
-    Liquid::Template.file_system = StubFileSystem.new(
-      'product' => "Product: {{ product.title }} ",
-      'product_alias' => "Product: {{ product.title }} ",
-    )
-
-    assert_template_result("Product: Draft 151cm Product: Element 155cm ",
-                           "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
-  end
 end