GWT used be able to produce and use *.gwtar files before to speed up (at least a little bit) the transpilation - libraries could come with their *.gwtar files and only modified code would need to be fully rebuilt.
I am working on a large GWT application that allow for more modules to be added by the product's end user - kind of like plugins. These modules are specifically packaged and must obey certain contracts. During deployment we rebuild the app using the combined code (existing + module being added). The production build process takes significant time already but we can live with it in development, we use Super Dev mode for the rest. However, end users see multi-minute builds (say 10-20!) when they add a module and that is rather inconvenient. *.gwtar files no longer help/work - we noticed that they started breaking some stuff with GWT 2.7, actually (compiler reported errors with 3rd party libraries but only when *.gwtars were used).
GWT isn't really made to be able to have independently compiled modules talk to one another without rebuilding (that would be a very welcome feature), but we are looking for a way to leverage GWT incremental compilation to speed up the process and enhance our end users' experience. I have not been able to find the documentation on where the intermediate artifacts are stored and whether/how they can be reused.
While the concern about stability of this system exists - i.e. the files may change from release to release, the greatest time is taken by the base product, which also supplies the tooling. Thus, we can change this with every release too, as needed - even if plugins don't come with these artifacts, the transpilation may still be faster.
Can anyone, please, help me figure out how to leverage this (GWT 2.8 incremental transpilation) for the above use case?