On Thu, 8 Sep 2022 09:45:03 GMT, Magnus Ihse Bursie <i...@openjdk.org> wrote:
>> Actually, this is not an entirely correct description. EXTRA_DEPS points to
>> the `depend` javac plugin itself in buildtools. Once built, this is unlikely
>> to change. Dependency on the API changes themselves happen on a higher
>> level, in `CompileJavaModules.gmk`, where we add a dependency of the
>> outputted `pubapi` file for modules we depend on.
>>
>> (I did have to look this up, though)
>
> I looked up what kind of dependencies we are passing in through `DEPEND`.
> None, it turns out. It is not used. So that is not a worry. We might consider
> removing it. Sending in exceptional dependencies like that is never a good
> design decision. If it ever happens again that this would be the only
> acceptable solution, we can re-add the `DEPEND` argument.
>
> But that basically mean that Jan's patch might be okay, after all. `DEPENDS`
> does not exist, and I want to remove it. `EXTRA_DEPS` is only modified if we
> change the `depend` javac plugin. I am willing to sacrifice automatic
> recompilation of all Java classes if that is changed.
Ok I was wrong about what EXTRA_DEPS was used for, I read the code too hastily.
However, the dependency declaration for the pubapi files from other modules is
added in make/CompileJavaModules.gmk like this:
$($(MODULE)_COMPILE_TARGET): $(foreach d, $(call FindDepsForModule, $(MODULE)),
\
$(call SetupJavaCompilationApiTarget, $d, \
$(if $($d_BIN), $($d_BIN), $(JDK_OUTPUTDIR)/modules/$d)))
So this still doesn't change my main point. The pubapi files only appear on the
dependency declaration for `$($(MODULE)_COMPILE_TARGET)`. This means that with
the current patch, we will not recompile the full module when a parent module
has a change to the pubapi. The Depend plugin needs to see the pubapi files in
`$$?` for that to happen.
One could also make the case for using DEPEND when adding such a dependency
instead of referencing `$($(MODULE)_COMPILE_TARGET)` in explicit rules. It
would be more inline with more recent design patterns.
-------------
PR: https://git.openjdk.org/jdk/pull/10104
