elijahbenizzy left a comment

This allows you to specify defaults if your action does not write. Inthe majority of cases they will be none, but this allows simple (static)arbitrary values. This specifically helps with the branching case --e.g. where you have two options, and want to null out anything itdoesn't write. For instance, an error and a result -- you'll only everproduce one or the other.This works both in the function and class-based approaches -- in thefunction-based it is part of the two decorators(@action/@streaming_action). In the class-based it is part of the class,overriding the default_reads and default_writes property functionWe add a bunch of new tests for default (as the code to handle multipleaction types is fairly dispersed, for now), and also make the naming ofthe other tests/content more consistent.Note that this does not currently work with settings defaults toappend/increment operations -- it will produce strange behavior.This is documented in all appropriate signatures.This also does not work (or even make sense) in the case that thefunction writes a default that it also reads. In that case, it willclobber the current value with the write value. To avoid this,we just error out if that is the case beforehand.