Caching of (not only) test results about bleep

[oyvindberg]

Not at all really, Bleep just defers to Bloop. See for instance the implementation of Test - it's just forwarding through BSP.

Bloop on the other hand does keep some state to avoid needless recompiling, particularly through zinc.

For tests it is not feasible to safely cache test results on the JVM, as you would need both some proof of pureness and a digest of the transitive call graph for each test - like what unison does.

The only cache in Bleep is for for resolving dependencies through coursier. What is done there is the definition of a dependency has been heavily constrained from sbt (dropping a decade of incredibly obtuse ivy-stuff nobody uses), so that it's much easier to cache. Constraining the dependency "language" makes it much easier to cache, so this is a large part of why Bleep loads builds almost instantly - it trades disk space for speed.