Attic strategy is potentially broken

[jhclark]

By moving some files to the attic, we risk breaking future runs. Example: task t1 creates an absolute symlink to some file in its own directory. Task t2 then runs 2 different realizations based on that file. Task t2 writes a config file that depends on task t1's symlink. We then rerun task t1, but then only one realization of task t2. Now, if we add a task t3, one of its realizations will fail.

TODO: Flesh out the example.

[jhclark]

Note: This is only an issue if we want to separate the issues of "comparability" and "reproducibility". As it stands, we cannot reproduce some non-comparable workflow states, but we can reproduce all comparable workflow states.