rails/rails — pull request #13599 by vipulnsward (2014-01-05 18:14:24+00:00)
Title: Fix regression on has many association callback repeating records.

3af4ae82e587b12664626e7b22bc6cc21ebbca2e introduced a regression on has many association, where calling a child from parent in child's callback

resulted in same child records getting added repeatedly to target.

Fixes #13387.