[Seaside] A quick note about backtracking, #states, #snapshotCopy and #restoreFromSnapshot:

[Sven Van Caekenberghe]

Hi,

A quick note about backtracking, #states, #snapshotCopy and #restoreFromSnapshot: since I lost quite some time figuring this out.

In order to make backtracking work, you need to implement #states on your component, we all know that.

However, if you put a more complex object with nested sub objects in your states collection, this will fail unless you also customise (i.e. override) both #snapshotCopy and #restoreFromSnapshot: because the default implementation only does a #shallowCopy which ignores #postCopy.

I did not find anything about this in http://book.seaside.st and this strikes me as both quite important and hard to figure out.

Sven