It turns out that we have some outputs (accumulators) for which
it only makes sense to have a `DependencyIndex` (they don't have
individual keys to identify).
We also track whether reset is required at the ingredient level.
For tracked struct fields, we were not using `push_mut`,
and I think that was an oversight.
The plan is to do a "dependent ingredient" interlinking pass
once the database is constructed.
I realized I can do this better:
* require that outputs are DatabaseKeyIndex, fewer unwraps,
more clearly justified
* when we validate result of tracked fn, also validate its outputs
(this is incompletely implemented, would ideally be separated
into its own commit, but I'm short for time)
The last step will allow us to keep the memoized results for
assigned values and means we don't have to eagerly clear them.
If we see an "assigned value" that is not verified in the current
revision, it can simply be considered dirty.
We can still delete them when entities are deleted, but they're
less special.
We don't do anything with this info right now besides log it,
but the logs show we are reporting it at the right times
in the `specify_tracked_fn_in_rev_1_but_not_2` test
(also fix an oversight in the test where it was creating a new input
each time).
We don't do anything with this info right now besides log it,
but you can see that we are reporting it at the right times
in the `specify_tracked_fn_in_rev_1_but_not_2` test
(also fix an oversight in the test where it was creating a new input
each time).
