sbt/sbt — pull request #1122 by gkossakowski (2014-02-17 16:01:21+00:00)
Title: Include value of `nameHashing` flag in `CompileSetup`.

The CompileSetup class is being used to detect changes to arguments of
incremental compiler that affect result of compilation and trigger
recompilation. Examples of such arguments include, the target (output)
directory, Scala compiler options, Scala compiler version, etc.

By adding `nameHashing` to CompileSetup we have a chance to handle change
to that flag smoothly by throwing away old Analysis object and starting
with an empty one. That's implemented in AggressiveComile by extending
the logic that was responsible for detection of changes to CompileSetup
values. Thanks to this change we fix #1081.

Analysis formats has been updated to support persisting of newly added
value in CompileSetup. We used to not store the value of `nameHashing`
flag in persisted Analysis file and infer it from contents of relations
but that leads to issue #1071 when empty relations are involved. Given
the fact that CompileSetup stores `nameHashing` value now, we can just
use it when reading relations and fix #1071. This requires reading/writing
compile setup before reading relations. I decided to make that change even
if there's a comment saying that reading/writing relations first was done
intentionally.