automatic modules leaking types when using addmods

[Paul Bakker]

I understand this statement from the perspective of automatic modules. Not so much from the perspective of named modules however. Why would it be necessary to give implicit readability to all automatic modules when you're just explicitly using a single one?

Paul

> On 25 Apr 2016, at 02:38, Paul Benedict <pbenedict at apache.org> wrote:
> 
> Automatic modules live in a classpath-like world. Everything is exported to each other. You use this feature if you don't have time to migrate to a modular architecture.
> 
> On Apr 24, 2016 3:01 PM, "Paul Bakker" <paul.bakker.nl at gmail.com <mailto:paul.bakker.nl at gmail.com>> wrote:
> So when modules B, C and D are automatic modules and named module A depends on B, A also gets implicit readability to C and D?
> What is the reasoning behind this automatic implicit readability? It makes migration less reliable I think, because it hides what dependencies a module really has.
> 
> Paul
> 
> 
> > On 24 Apr 2016, at 21:06, Alan Bateman <Alan.Bateman at oracle.com <mailto:Alan.Bateman at oracle.com>> wrote:
> >
> >
> > On 24/04/2016 10:57, Paul Bakker wrote:
> >> Hello,
> >>
> >> Another question related to automatic modules.
> >> I have the following code:
> >>         import com.fasterxml.jackson.core.JsonFactory;
> >>         ...
> >>      JsonFactory f = new JsonFactory();
> >>      System.out.println(f.getCodec());
> >>
> >> This code clearly depends on jackson.core. So my module-info contains:
> >>      requires jackson.core;
> >>
> >> This is as expected. I can change the module-info to the following however (removing the dependency on jackson.core):
> >>      requires jackson.databind;
> >>
> >> At first sight, this fails to compile as expected, because the JsonFactory type comes from jackson.core, not from jackson.databind.
> >> But when I add "-addmods jackson.core" to my build command, it builds successfully! That's not what I would expect, because my module doesn't declare a dependency on jackson.core. Why does this happen? I would expect that the -addmods adds the module to the available modules, but does not magically add read edges to named modules.
> >> When removing the "jackson.databind" requires in my module-info, it fails to compile again, so it looks like jackson.databind somehow leaks types from jackson.core to my module.
> >>
> >> The build command I use is the following:
> >>      javac -mp mods -addmods jackson.core -d out -modulesourcepath src $(find src -name '*.java')
> >>
> >>
> > Are both jackson.databind and jackson.core automatic modules in this scenario? I assume so, in which case I think what you are seeing is correct (meaning it should compile). The reason is that automatic modules read all other modules and they also grant implied readability to all other automatic modules. In this example then it is as if jackson.databind `requires public jackson.core` so your module will read jackson.core.
> >
> > -Alan
>