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, 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 e61b23f842..bc670c3e76 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -110,7 +110,7 @@ class DateTime
   # instance time. Do not use this method in combination with x.months, use
   # months_since instead!
   def since(seconds)
-    self + Rational(seconds.round, 86400)
+    self + Rational(seconds, 86400)
   end
   alias :in :since