DateTime#<=> return nil when compare to the invalid String as Time.

before:

    p Time.now ==  'a'  # => false
    p Time.now <=> 'a'  # => nil

    require 'active_support'
    require 'active_support/core_ext'

    p Time.now ==  'a'  # => false
    p Time.now <=> 'a'  # => invalid date (ArgumentError)

and on ruby 2.2, Time.now == 'a' warning.

    warning: Comparable#== will no more rescue exceptions of #<=> in the next release.
    warning: Return nil in #<=> if the comparison is inappropriate or avoid such comparison.

after:

- Error handling.
- Quiet warnings.

1 files changed, 1 insertions, 1 deletions

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 55ad384f4f..95617fb8c2 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -168,7 +168,7 @@ class DateTime
     if other.kind_of?(Infinity)
       super
     elsif other.respond_to? :to_datetime
-      super other.to_datetime
+      super other.to_datetime rescue nil
     else
       nil
     end