From 19e287dda27ac38ad28c0c53f661def3ce331297 Mon Sep 17 00:00:00 2001
From: Ian Ker-Seymer <ian.kerseymer@shopify.com>
Date: Thu, 3 Apr 2025 15:39:14 -0400
Subject: [PATCH] Gracefully empty property in map filter

---
 lib/liquid/standardfilters.rb            |  8 ++---
 test/integration/standard_filter_test.rb | 42 +++++++++++++++++++++---
 2 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/lib/liquid/standardfilters.rb b/lib/liquid/standardfilters.rb
index c7a841cc..4d69f5bc 100644
--- a/lib/liquid/standardfilters.rb
+++ b/lib/liquid/standardfilters.rb
@@ -536,11 +536,11 @@ module Liquid
     # @liquid_syntax array | map: string
     # @liquid_return [array[untyped]]
     def map(input, property)
-      if property.nil?
-        raise_property_error(property)
-      end
-
       property = Utils.to_s(property)
+
+      # Return the input array if property is empty (no-op)
+      return InputIterator.new(input, context).to_a if property.empty?
+
       InputIterator.new(input, context).map do |e|
         e = e.call if e.is_a?(Proc)
 
diff --git a/test/integration/standard_filter_test.rb b/test/integration/standard_filter_test.rb
index 86cdadaa..ddf66333 100644
--- a/test/integration/standard_filter_test.rb
+++ b/test/integration/standard_filter_test.rb
@@ -560,15 +560,47 @@ class StandardFiltersTest < Minitest::Test
     end
   end
 
-  def test_map_returns_empty_with_no_property
-    foo = [
+  def test_map_with_nil_property
+    array = [
+      { "handle" => "alpha", "value" => "A" },
+      { "handle" => "beta", "value" => "B" },
+      { "handle" => "gamma", "value" => "C" }
+    ]
+
+    assert_template_result("alpha beta gamma", "{{ array | map: nil | map: 'handle' | join: ' ' }}", { "array" => array })
+  end
+
+  def test_map_with_empty_string_property
+    array = [
+      { "handle" => "alpha", "value" => "A" },
+      { "handle" => "beta", "value" => "B" },
+      { "handle" => "gamma", "value" => "C" }
+    ]
+
+    assert_template_result("alpha beta gamma", "{{ array | map: '' | map: 'handle' | join: ' ' }}", { "array" => array })
+  end
+
+  def test_map_with_value_property
+    array = [
+      { "handle" => "alpha", "value" => "A" },
+      { "handle" => "beta", "value" => "B" },
+      { "handle" => "gamma", "value" => "C" }
+    ]
+
+    assert_template_result("A B C", "{{ array | map: 'value' | join: ' ' }}", { "array" => array })
+  end
+
+  def test_map_returns_input_with_no_property
+    input = [
       [1],
       [2],
       [3],
     ]
-    assert_raises(Liquid::ArgumentError) do
-      @filters.map(foo, nil)
-    end
+    result = @filters.map(input, nil)
+    assert_equal(input.flatten, result)
+
+    result = @filters.map(input, '')
+    assert_equal(input.flatten, result)
   end
 
   def test_sort_works_on_enumerables