Description of problem:

This is a known interaction in Rails (< 4.1.6) between ActiveRecord::Base#becomes and ActiveRecord::Base#save!. The issue is that the save! call creates an UPDATE like this: 


    UPDATE "hosts" SET ... WHERE "hosts"."type" IN ('Host::Managed') AND "hosts"."id" = 18  [...]


The WHERE clause there matches nothing, because the record in the database still has a type of Host::Discovered. An UPDATE on an empty set doesn't raise an error, so execution continues, and the transaction is not rolled back. This means, if you convert a host from discovered to managed and then save! it inside a transaction, all of the SQL statements that handle deleting the discovered attributes, adding entries to hosts/puppetclasses/operating systems/hostgroups etc succeed, and at the end you are left with a broken discovered host with no attributes, that can't even be deleted because of database constraints.

This is only an issue in Rails versions <= 4.1.5, it was fixed with this commit in Rails 4.1.6: https://github.com/rails/rails/commit/257d65ed2ceb14dca6b1319355ed4f8a73540498 . Here is the associated issue: https://github.com/rails/rails/issues/14785

Version-Release number of selected component (if applicable):
6.2.0

How reproducible:
100%

Steps to Reproduce:
1. Create a discovered host
2. Inside a transaction
  a. Use the HostConverter.to_managed to convert the host from discovered to managed
  b. Call host.save!

Actual results:
After the transaction, the host is of type Host::Discovered, but its attributes have been nilled out. Hostgroups/puppetclasses/operating systems all have entries related to the discovered host, which prevents me from deleting it.

Expected results:
After the transaction, the host is of type Host::Managed

Additional info:
from foreman-rake console, I ran ActiveRecord::VERSION::STRING and it output "4.1.5". If we can bump up to any Rails version >= 4.1.6, this issue should go away without any additional work.