Comment by lkitching

There's been a fair amount of churn in the ecosystem, even if the language itself has been very stable. Leiningen was ubiquitous 5-6 years ago, but if you switched to using deps for dependency management you lost the ability to run tests or build uberjars and had to manually re-create these on a per-project basis. Now there's tools.build, but that also requires you to manually write essentially the same tasks for basic functionality in each project. Leiningen and tools.deps also seem to resolve depedencies differently, so you can run into issues simply by migrating from one to the other.