added String#to_date documentation to Rails 4 upgrade guide

[ci skip]

1 files changed, 13 insertions, 0 deletions

diff --git a/guides/source/4_0_release_notes.md b/guides/source/4_0_release_notes.md
index 8be7a86d20..ff4d30b4c0 100644
--- a/guides/source/4_0_release_notes.md
+++ b/guides/source/4_0_release_notes.md
@@ -173,6 +173,19 @@ Please refer to the [Changelog](https://github.com/rails/rails/blob/master/activ
 
 * `Object#try` will now return nil instead of raise a NoMethodError if the receiving object does not implement the method, but you can still get the old behavior by using the new `Object#try!`.
 
+* `String#to_date` now raises `Argument Error: invalid date` instead of `NoMethodError: undefined method 'div' for nil:NilClass`
+  when given an invalid date. It is now the same as `Date.parse`, and it accepts more invalid dates than 3.x, such as:
+
+  ```
+  # ActiveSupport 3.x
+  "asdf".to_date # => NoMethodError: undefined method `div' for nil:NilClass
+  "333".to_date # => NoMethodError: undefined method `div' for nil:NilClass
+
+  # ActiveSupport 4
+  "asdf".to_date # => ArgumentError: invalid date
+  "333".to_date # => Fri, 29 Nov 2013
+  ```
+
 ### Deprecations
 
 * Deprecate `ActiveSupport::TestCase#pending` method, use `skip` from MiniTest instead.