Summary

#29333 introduced a deprecation warning for transaction blocks that are exited with break, return or throw which has a couple of problems which @eileencodes brought to my attention (#29333 (comment)).

That deprecation warning was introduced for code like

Timeout.timeout(1) do
  Example.transaction do
    example.update_attributes(value: 1)
    sleep 3 # simulate something slow
  end
end

because it wasn't expected that the timeout would commit the transaction. However, the warning says the next version of rails will raise an exception and it would also be unexpected for that code to not result in a Timeout::Error exception. So the first commit in this PR changes the deprecation warning message to remove the mention of raising.

The other problem is with deprecation warnings from returns out of a transaction block that hasn't made any writes to the transaction, where it doesn't matter if the transaction is rolled back or committed. E.g.

with_lock do
  return if some_crtieria_met?

  # do work
end

The second commit in this PR avoids that deprecation warning by marking open transactions as having written on the first write query, then making the warning conditional on the current transaction having written.

Other Information

Since the #29333 hasn't been released, I've just edited the existing CHANGELOG entry for it.