Versioning in the java platform module system - proof of concept

[Alan Bateman]

On 01/01/2018 18:14, Tom De Wolf wrote:
> I am working out a proof of concept to use the module version property and
> the version of a ‘requires’    in a useful manner. Details and a link to
> github can be found on:
>
> https://devcreativity.wordpress.com/2017/12/29/semantic-versions-in-java-9-modules-as-a-safety-net/
>
> However, I stumbled on behaviour I don’t completely understand:
> - printing out the module.getDescription().version() showed a non-empty
> value for the jdk modules, explicit modules which got the version through
> ‘jar --module-version’, and automatic modules like spring.core
> - as I understand the Requires.compiledVersion() gets a value when the
> dependency module has a version in module.getDescription().version()
>
> The latter is seen when requiring explicit modules, however requiring an
> automatic module does not fill in the compiledVersion? Why is that, even
> when the module.getDescription().version() shows a value (e.g. spring.core)?
>
> What is used for an automatic module such as spring.core to show
> 5.0.0.RELEASE as version?
>
Requires::compiledVersion returns the module version if it is recorded 
in the module-info.class. javac has chosen to record the version of 
dependences when they are explicit modules. It doesn't record (or know 
anything about) the version of automatic modules at this time. It 
potentially could. Alternatively a build tool could record it (it 
doesn't have to be javac).

-Alan