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Last active May 25, 2018 04:46
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the dup method in ruby
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dup_ruby.md

What's this #dup method do?

Doing a code read today in our monthly 10% time I started to read and document an internal event sourcing framework we've built in our team. I stumbled across the .dup method and so naturally I got sidetracked (losing sight of the high level) with StackOverflow posts, Ruby-Doc and my own IRB comparisons between it, and another method that appears quite similar -clone.

Importantly dup differs from clone in that it duplicates the object as a completely new record (if it's an ActiveRecord object no id is assigned however if it's a PORO a new object_id is assigned so it's completely different). The duped object has no direct assocation with the original at all. Thus, if you modify a duped object, you won't change the original object and that's because it's a “shallow” copy – it copies the object’s attributes only, not its associations.

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