Compile time vs. runtime deps

[Paul Sandoz]

On Jul 13, 2012, at 6:12 AM, David Holmes wrote:

> On 12/07/2012 11:26 PM, Jaroslav Tulach wrote:
>> Dne Čt 12. července 2012 10:54:27, David Holmes napsal(a):
>>>>> I don't see why I need to make the distinction to the compiler. I
>>>>> declare an optional dependency and at compile-time it is, or isn't
>>>>> found.
>>>> 
>>>> That could produce different result during the compilation. The
>>>> compilation
>>>> could either succeed or fail. Javac and IDEs need to know whether the
>>>> optional (in runtime) library should or should not be on the compilation
>>>> "classpath".
>>> You mean the tools are going to dynamically examine my
>>> module-info.java/class and use it to determine what they should set
>>> modulepath/classpath to ???
>> 
>> Hello David,
>> yes, that is the jigsaw plan. module-info.java is going to be the source of
>> compilation classpath for javac. It is supposed to save us for "classpath
>> hell". However, unlike other tools that shield us from such "hell", the
>> current design addresses just a half (at most) of the problem. Should it stay
>> this way, we are going to be faced to "classpath nightmare"...
>> 
>>> That is not something I would have expected at all.
>> 
>> I guess you are looking at Jigsaw from VM perspective, then! That is OK, but
>> the Jigsaw tries to define (a bit of) tooling story too.
> 
> Nothing to do with VM perspective. I just don't expect my compiler or IDE to go and find a missing module for me. If the module is needed and missing then I get an error at compilation time. If the dependency is listed in module-info.java I still get an error at compilation time. Unless you expect the tool to try and resolve the problem (which I don't) then I don't see how adding something in module-info.java makes a difference.
> 

Do you expect that every developer, when checking out and building a project with such dependencies, deal with compile time errors?

With the right information in the module-info.java compile-time dependencies can be downloaded automatically from repositories i.e. just like Maven does.

Paul.