* Aristo: Merge `delta_siblings` module into `deltaPersistent()`
* Aristo: Add `isEmpty()` for canonical checking whether a layer is empty
* Aristo: Merge `LayerDeltaRef` into `LayerObj`
why:
No need to maintain nested object refs anymore. Previously the
`LayerDeltaRef` object had a companion `LayerFinalRef` which held
non-delta layer information.
* Kvt: Merge `LayerDeltaRef` into `LayerRef`
why:
No need to maintain nested object refs (as with `Aristo`)
* Kvt: Re-write balancer logic similar to `Aristo`
why:
Although `Kvt` was a cheap copy of `Aristo` it sort of got out of
sync and the balancer code was wrong.
* Update iterator over forked peers
why:
Yield additional field `isLast` indicating that the last iteration
cycle was approached.
* Optimise balancer calculation.
why:
One can often avoid providing a new object containing the merge of two
layers for the balancer. This avoids copying tables. In some cases this
is replaced by `hasKey()` look ups though. One uses one of the two
to combine and merges the other into the first.
Of course, this needs some checks for making sure that none of the
components to merge is eventually shared with something else.
* Fix copyright year
* Remove `chunkedMpt` from `persistent()`/`stow()` function
why:
Proof-mode code was removed with PR #2445 and needs to be re-designed.
* Remove unused `beStateRoot` argument from `deltaMerge()`
* Update/drastically simplify `txStow()`
why:
Got rid of many boundary conditions
details:
Many pre-conditions have changed. In particular, previous versions
used the account state (hash) which was conveniently available and
checked it against the backend in order to find out whether there
was something to do, at all. Currently, only an empty set of all
tables in the delta layer has the balancer update ignored.
Notable changes are:
* no check against account state (see above)
* balancer filters have no hash signature (some legacy stuff left over
from journals)
* no (shap sync) proof data which made the generation of the a top layer
more complex
* Cosmetics, cruft removal
* Update unit test file & function name
why:
Was legacy module
Jordan Hrycaj