Root cache directory
Raised here (!1013 (comment 129888354)), it makes sense to move some directories out of artifact cache and into the top level cache structure, in particular
tmp which will be used by the source cache once that's implemented (see #440 (closed)). As many of these directories should be in the same directory we should deprecate the current
artifactdir options, and have them placed in this root directory.
Issue warnings for when
builddirare set by a user
rootcachediroption under which
casand the default for