Fix DateTime comparison with DateTime::Infinity object

Fixes #16406

3 files changed, 8 insertions, 1 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 7514faabb2..03e8d73ea7 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Fix DateTime comparison with DateTime::Infinity object.
+
+    *Rafael Mendonça França*
+
 *   Added Object#itself which returns the object itself. Useful when dealing with a chaining scenario, like Active Record scopes:
 
         Event.public_send(state.presence_in([ :trashed, :drafted ]) || :itself).order(:created_at)
diff --git a/activesupport/lib/active_support/core_ext/date_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
index 289ca12b5e..dc4e767e9d 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -161,7 +161,9 @@ class DateTime
   # Layers additional behavior on DateTime#<=> so that Time and
   # ActiveSupport::TimeWithZone instances can be compared with a DateTime.
   def <=>(other)
-    if other.respond_to? :to_datetime
+    if other.kind_of?(Infinity)
+      super
+    elsif other.respond_to? :to_datetime
       super other.to_datetime
     else
       nil
diff --git a/activesupport/test/core_ext/range_ext_test.rb b/activesupport/test/core_ext/range_ext_test.rb
index cfe31b75e8..98c4ec6b5e 100644
--- a/activesupport/test/core_ext/range_ext_test.rb
+++ b/activesupport/test/core_ext/range_ext_test.rb
@@ -16,6 +16,7 @@ class RangeTest < ActiveSupport::TestCase
   def test_date_range
     assert_instance_of Range, DateTime.new..DateTime.new
     assert_instance_of Range, DateTime::Infinity.new..DateTime::Infinity.new
+    assert_instance_of Range, DateTime.new..DateTime::Infinity.new
   end
 
   def test_overlaps_last_inclusive