No way to set old values when element has been removed from the model.

[mmacfadden]

Versions

• Convergence Version: 1.0.0-rc.12

Describe the Bug
The code here:

https://github.com/convergencelabs/convergence-server/blob/8ded7fa5adaac3690520c98f53b0843072adab7d/src/main/scala/com/convergencelabs/convergence/server/backend/services/domain/model/RealtimeModel.scala#L239

Will insert None values or bogus values into the applied operations if the operation is noop'ed and the real time element is not in the model anymore.

Expected Behavior
We have discussed potentially keeping deleted elements around in a recycle bin while conflicting operations could still come in.

[mmacfadden]

Another option is to update the schema to allow for null values in this condition. Right now we have the combination of not being able to compute the old value, but the database needing it.