Now, as for SNAPSHOTs, remember SBT uses *ivy* which means SNAPSHOTS are the wrong way of doing it. We really should be using integrations and someone needs to figure out how to do it the right ivy way, or we're just asking for issues.Be deleting artifacts you're *asking* for problems from users and resolution nightmares. Let's not add to an already terrible situations. Let's not fight Ivy if we have to use it.
Changes in artifactsSome people, especially those coming from maven 2 land, like to use one special revision to handle often updated modules. In maven 2 this is called a SNAPSHOT version, and some argue that it helps save disk space to keep only one version for the high number of intermediary builds you can make whilst developing.
Ivy supports this kind of approach with the notion of "changing revision". A changing revision is just that: a revision for which Ivy should consider that the artifacts may change over time. To handle this, you can either specify a dependency as changing on thedependency tag, or use the changingPattern and changingMatcher attributes on your resolvers to indicate which revision or group of revisions should be considered as changing.
Once Ivy knows that a revision is changing, it will follow this principle to avoid checking your repository too often: if the module metadata has not changed, it will considered the whole module (including artifacts) as not changed. Even if the module descriptor file has changed, it will check the publication data of the module to see if this is a new publication of the same revision or not. Then if the publication date has changed, it will check the artifacts' last modified timestamps, and download them accordingly.
Maven versions can contain a string literal to signify that a project is currently under active development. If a version contains the string “-SNAPSHOT,” then Maven will expand this token to a date and time value converted to UTC (Coordinated Universal Time) when you install or release this component. For example, if your project has a version of “1.0-SNAPSHOT” and you deploy this project’s artifacts to a Maven repository, Maven would expand this version to “1.0-20080207-230803-1” if you were to deploy a release at 11:08 PM on February 7th, 2008 UTC. In other words, when you deploy a snapshot, you are not making a release of a software component; you are releasing a snapshot of a component at a specific time.
uniqueVersion: The unique version takes a true or false value to denote whether artifacts deployed to this repository should get a uniquely generated version number, or use the version number defined as part of the address.
The revision can be given as a fixed one (1.5.2, for instance) or as a latest (or dynamic) one. Several possibilities for dynamic revisions are implemented in Ivy:
selects the latest revision of the dependency module.
selects the latest revision of the dependency module with at least the specified status.
Principal Engineer, Gradleware
Creator, Spock Framework