sbt should reject projects with dependencies on multiple versions of the same artifact

[harrah]

I recent was bitten when a project had a direct dependency on one version of an artifact, but an indirect dependency on a different version of the same artifact. The result was to silently place the indirect dependency on the classpath, leading to extremely difficult to diagnose compilation errors.

IMHO, sbt should refuse to accept a project definition in such cases, and provide helpful diagnostics about the conflicting versions and where they come from in the dependency graph.

[harrah]

IMPORTANT This project has moved to https://github.com/sbt/sbt. This issue still exists to avoid dead links, but GitHub limitations prevent the original issue from being correctly preserved here. Please see sbt/sbt#603 for the full issue and to comment.