Compile time vs. runtime deps was: Requires optional permits

[Jaroslav Tulach]

Dne St 11. července 2012 08:59:20, Paul Sandoz napsal(a):
> On Jul 11, 2012, at 8:28 AM, David Holmes wrote:
> >> If there is an optional dependency then presumably code in the depending
> >> module must be using types exported by the optional dependent module.
> >> Reflection is one way to use those types, another is a little bit of
> >> indirection (static or via reflection) to static usage of those types.> 
> > I think this is wrong. I can use the optional module reflectively so that
> > there is no direct type dependency (else the dependency would not be
> > optional!).
> Yes, but the dependency can also be direct at compile time and optional at
> install time, it's just that "requires optional" does not differentiate
> between the two cases.
> > There is no reason that it needs to be present at compile time if I don't
> > use those types directly. I would think the above statement from the Big
> > Picture should read:
> > 
> > "A foo module must still be available when compiling bar _if_ code in bar
> > depends upon types declared in foo."
> That's seems reasonable to me. I will try and get some clarification on
> this.
> 
> Perhaps the resolver should output warnings at compile time for optional
> modules that are not present to augment any "cannot find symbol" compiler
> errors?

I believe both cases are possible. I can have optional dependency I need to 
compile against and I can as well have another optional dependency I don't 
need to compile against.

There needs to be a way to express that properly to Jigsaw runtime as well as 
Javac.

This is another example when runtime and compile time dependencies may  
differ. The first one I know is the list of annotation processor providing 
modules to be present when compiling, but not during execution.

Time to introduce "requires compile m at 1.0"?
-jt