Aslak Hellesøy wrote: > Imagine I have 3 sub projects a,b and c with the following dependencies: > a<-b<-c. > > The 1st time I run reactor everything is built. Then I modify b and run > reactor again. a doesn't depend on b and therefore shouldn't be rebuilt. > The reactor should now only build b and c. > > I think this can be implemented quite simply by doing some date > comparisons between java sources and classes in each project.
Do you happen to know unix utility called 'make'? :-D I hope that at some point Maven will be able to take advantage of 30 years of experience of the make community. The problem is that determinig weather the project is 'up to date' is not so simple anymore. Suppose you have your project 'b' that depends on project 'a'. You are asking maven to rebuild project 'b', so maven tries to determine if project's dependencies are up to date. Now. Most of the dependencies are binary only, downloaded from remote repo, some of the dependencies however are available in the users' workspace (think Eclipse) in the source form. Maven would have to keep some sort of registry in the users' MAVEN_LOCAL_HOME that would associate artifacts from the repository with projects in the users' workspace (in Eclipse sense, or just on the local file system). Using this registry maven would be able to detect that it should check if project 'a' in the users's workspace is up-to-date before proceeding with building project 'b'. How could maven determine if the artifact from project 'a' sitting in the repository is up to date? I guess it should start by determing what plugin is responsible for generating and deploying that particular artifact type. Then it should somehow discover the chain of plugins that ineroperate to provide the artifact-generating plugin with it's input. And then it should go over the plugin chain bottom to top and ask each plugin if it's output files seem to be newer than it's input files. In a simple scenario java plugin would be consulted, and then jar plugin. The chain might be much longer, and possibly branched, for more complicated setups involving aspects, grammars, xdoclet, stub/tie generators and the like. If any of the plugins detects new/modified source files it should perform a rebuild of it's piece of work, and all plugins down the chain (or branch, to be more specific) should perform an unconditional rebuild. As a result, we expect an updated version of the project's 'a' artifact being deployed to the local repository, if any of the project's a source files changed. As you see this is rather complicated process... Luckily Maven-new will allow us to define more strict plugin contracts, including optional contracts like the ability to participate in artifact processing pipelines and incremenatal/partial rebuilds. R. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
