Right off the bat, the restriction in GAE that no threads be created will affect a few, small sections of Tapestry.
In the larger scheme of things, a tapestry-googleappengine library may require a few things:
- Make the GAE services (such as UserService) injectable
- Support for JDO (much like tapestry-hibernate, today)
- Other, unforseen
Also, depending on the license of GAE (and availabilty through Maven) may need to host such a library at Tapestry360.