More from the JEP 261 backlog

[Stephan Herrmann]

In thread "[module-imports] Importing java.se" Alex mentioned a planned update 
to JEP 261. Now I wonder, if this is a suitable point in time to ask again about 
another specification issue in this area.

JEP 261 lists among the new features a compiler option "--release", which was 
contributed by JEP 247.

Now, JEP 261 is scope SE, but it "includes" JEP 247 which is declared as scope JDK.

Similar to the discussion in the other thread, this does not answer, how a 
compiler which is not part of a JDK can possibly implement the "--release" option.

Back at the time, we (Eclipse) had shyly asked for a specification of the format 
of file ct.sym. This specification was denied (it's internal, subject to 
change), and also the idea to provide an API instead didn't - to the best of my 
knowledge - bear any fruit.

As a result the Eclipse compiler had to be based on reverse engineering of 
existing ct.sym files, and more than once the resulting heuristics were broken 
by changes in the file format.

It seems that by now the file format has stabilized, so the easiest solution 
might be to
+ provide a specification of that format, and
+ provide information for which JDK versions this format can be assumed

Please remember, that the Eclipse compiler must as best as possible be able to 
work with any released JDK out there, past and future.

Most importantly, moving forward we'd appreciate some assurance that our 
implementation will not be broken again by future internal changes in OpenJDK.

thanks,
Stephan