Fix issue where duration where always rounded up to a second:

- Adding a Float as a duration to a datetime would result in the Float
  being rounded. Doing something like would have no effect because the
  0.45 seconds would be rounded to 0 second.

  ```ruby
    time = DateTime.parse("2018-1-1")
    time += 0.45.seconds
  ```

  This behavior was intentionally added a very long time ago, the
  reason was because Ruby 1.8 was using `Integer#gcd` in the
  constructor of Rational which didn't accept a float value.

  That's no longer the case and doing `Rational(0.45, 86400)` would
  now perfectly work fine.

- Fixes #34008

1 files changed, 9 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 2e465a0310..2f5ed35f46 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,12 @@
+*   Fix duration being rounded to a full second.
+    ```
+      time = DateTime.parse("2018-1-1")
+      time += 0.51.seconds
+    ```
+    Will now correctly add 0.51 second and not 1 full second.
+
+    *Edouard Chin*
+
 *   Deprecate `ActiveSupport::Multibyte::Unicode#normalize` and `ActiveSuppport::Multibyte::Chars#normalize`
     in favor of `String#unicode_normalize`