Compile time vs. runtime deps

[Paul Sandoz]

On Jul 13, 2012, at 11:38 AM, David Holmes wrote:

> On 13/07/2012 6:23 PM, Paul Sandoz wrote:
>> 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?
> 
> In general I don't expect users of a module to have to build it in the first place.

Users no, developers yes.


> I don't see why a developer of a module shouldn't have to deal with their own issues - they presumably understood that to use foo.bar they need to download and install foo.

It is not just the developer of the module, but a developer in general who is interested in building that module.

The expectation of many open source projects is that they should be easy to check out and build, otherwise it is a barrier to adoption.

Paul.