From 035a0db6ab7d59c865f68340892b53db66165c3f Mon Sep 17 00:00:00 2001
From: Marco Concetto Rudilosso <marco.rudilosso@shopify.com>
Date: Wed, 2 Apr 2025 11:01:51 +0200
Subject: [PATCH] Make all array filters that use `filter_array` util process
 empty string and nil correctly

---
 lib/liquid/standardfilters.rb            |  5 ++++-
 test/integration/standard_filter_test.rb | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/lib/liquid/standardfilters.rb b/lib/liquid/standardfilters.rb
index 4771b242..87a306b1 100644
--- a/lib/liquid/standardfilters.rb
+++ b/lib/liquid/standardfilters.rb
@@ -986,8 +986,11 @@ module Liquid
     attr_reader :context
 
     def filter_array(input, property, target_value, default_value = [], &block)
+      if property.nil?
+        raise_property_error(property)
+      end
+
       property = Liquid::Utils.to_s(property)
-      return default_value if property.empty?
 
       ary = InputIterator.new(input, context)
       return default_value if ary.empty?
diff --git a/test/integration/standard_filter_test.rb b/test/integration/standard_filter_test.rb
index 5c80fe3c..13369541 100644
--- a/test/integration/standard_filter_test.rb
+++ b/test/integration/standard_filter_test.rb
@@ -1033,6 +1033,24 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result(expected_output, template, { "array" => array })
   end
 
+  def test_where_with_empty_string_and_nil
+    array = [
+      "alpha",
+      "beta",
+      "gamma",
+    ]
+    template = "{{ array | where: '' | join: ' ' }}"
+    expected_output = "alpha beta gamma"
+    assert_template_result(expected_output, template, { "array" => array })
+
+    template = "{{ array | where: nil | join: ' ' }}"
+    exception = assert_raises(Liquid::ArgumentError) do
+      assert_template_result(expected_output, template, { "array" => array })
+    end
+
+    assert_equal("Liquid error (line 1): cannot select the property ''", exception.message)
+  end
+
   def test_where_with_value
     array = [
       { "handle" => "alpha", "ok" => true },