Improving Maven

I'm still at loggerheads with Maven. There are some specific problems that bother me and that I think could be improved while preserving its basic Maven-ness. Many of the problems center around issues when simultaneously developing more than one component at a time, i.e., when depending on SNAPSHOT versions. In fact a SNAPSHOT dependency is a fairly good indicator of misery; but some small improvements in Maven could reduce that pain point by a lot.

1. Maven knows that source produces artifacts, but it doesn't know that artifacts come from source. When Maven checks dependencies, it looks in local and remote repositories, but it doesn't know enough to build (or re-build) an artifact from source.

If Maven artifacts (at least locally deployed ones) had a backpointer to the location of the source project that produced them, then it would be possible to check dependencies against source. For instance, if project B depends on A, and I touch project A's code and then rebuild B, project A should also get rebuilt and installed. Similarly, if artifact A came from local source, then it almost certainly should NOT get replaced by an "updated" artifact from a remote repository, even if the remote artifact is newer; rather, local source code should always get honored. Extra points for a "mvn svn:update" command or the like, that would transitively sync the version control system to the latest code in all upstream projects.

2. SNAPSHOTs need to be versioned. When you're collaboratively working on two projects, and an API between them changes, the downstream build is broken until the upstream project gets refreshed. But right now that happens in a nondeterministic, asynchronous way: to Maven, all SNAPSHOTs are identical until, around midnight or so, it decides to refresh. Basing refreshes on an update interval is like filling up your car's gas tank every Friday: it's either too soon or too late. This needs to be deterministic. What I really want from SNAPSHOT is the idea of a fine-grained version number, that I will throw away upon release. It could be as simple as letting me say 1.3.0-SNAPSHOT-002, instead of just 1.3.0-SNAPSHOT.

3. Maven assumes that the internet is fast and reliable. It is neither, as anyone who works from coffeeshops and airports knows all too well. When Maven fails to get a network connection, or the network dies midway or times out, it needs to be able to roll back to a known and working state. Among other things, this means that updates need to be atomic across projects, or at least they need to be nondestructive. It also means that basic help should not rely on a network connection. Maven should not attempt to update plug-ins or projects during a 'clean' or 'help' operation.

I've got other problems with Maven - for instance, I think XML is nasty to work with, and I think that "convention over configuration" translates to "doesn't play well with others." Those things are harder to address while still keeping it Maven. But if the above three improvements were made, I think no one who loved Maven would be harmed, and a lot of other folks would be helped.

Eclipse awards

I spend most of my professional life feeling ignorant of one thing or another, so in the few areas where I do know at least a little bit I try to help out. For that reason I post pretty often to the eclipse.newcomer newsgroup. I'm proud to have been a finalist for the Eclipse Newcomer Evangelist award for the second year in a row: