jffi-update: trident7 fails to build

[Felix Natter <fnatter@gmx.net>]

hello debian-java,

I am in the process of packaging insubstantial [1]
(flamingo/substance/trident/...). It built ok a few weeks ago, but now
I am getting:

Execution failed for task ':trident:processResources'.
> Found class com.kenai.jffi.InvocationBuffer, but interface was
> expected

This is because of the libffi-java update in sid:
jessie (java): 1.0.2-11 WORKS
sid (java): 1.2.7-3 FAILS (see above)

(com.kenai.jffi.InvocationBuffer used to be an interface (1.0),
but now is an abstract class (1.2))

The problem is that I cannot find any reference to InvocationBuffer
in the insubstantial source code:

$ grep -R InvocationBuffer
$

Using search engines, I can only find solutions like updating ruby
runtime or jenkins for this kind of problem (which obviously does not
affect trident7).

Shall I ask here? https://github.com/jnr/jffi

[1] https://github.com/fnatter/insubstantial-debian
(the build can so far only be triggered with:
<install some dependencies manually>
$ dquilt push -a
$ debian/rules build)

Thanks and Best Regards,
-- 
Felix Natter