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For scala's bootstrapping, we need to be able to 'lock' the locker version of the compiler.
This means the locker should be compiled once based on the current source and get static for development. If the developer notices some kind of binary compatibility issue, then they can unlock the locker (usually be deleting a lock file) and the locker will be rebuilt based on source file changes.
Basically, all I need is the ability to wire a Task output (probably a boolean flag) to denote whether the compilation task should happen at all and have it bypass dependency analysis entirely.
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#128 for the full issue and to comment.