Before this change, the inmemory record was populated from values copied from the exisitng record.
It was no predictable to know in advance which values were required to correctly play onchange methods. Therefore all the values defined on the model were copied from the exising record to populate the inmemory record. The side effect of this approach was that in a lot of cases, a lot of useless values was copied leading to performance issue with computed fields.
With this change, we use the current record to call the onchange methods in an onchange context to avoid direct write to the database each time a new value is assigned by an onchange. At the end of the process, we restore the current record to its original state and return a dictionary with only the fields modified by the onchange.
Laurent Mignon (ACSONE)
Alexis de Lattre