* Redesign Sapling data model for V5 shared anchor and spends
The shared anchor is only present if there are any spends.
As part of this change, delete the manual PartialEq impl and its tests,
because we can derive PartialEq now.
* Stop creating a temporary Vec for the spend and output iterators
* Rename TransferData variants
Interactive rename using the following commands:
```sh
fastmod Spends SpendsAndMaybeOutputs
fastmod NoSpends JustOutputs
```
* Refactor out common sprout nullifier code
* Implement the AtLeastOne constrained vector type
This vector wrapper ensures that it always contains at least one element.
* Simplify Sapling TransferData using AtLeastOne
Also update the RFC to use AtLeastOne for Orchard.
* add sapling shielded data to transaction V5
* implement nullifiers
* test v5 in shielded_data_roundtrip
* Explicitly design serialization for Transaction V5
Implement serialization for V4 and V5 spends and outputs, to make sure
that the design works.
* Test serialization for v5 spends and outputs
Also add a few missing v4 tests.
* Delete a disabled proptest
* Make v5 transactions a top-level heading
And add a missing serialized type.
* Fix a comment typo
* v5 transaction RFC: split array serialization
Based on #2017
* RFC: explicitly describe serialized field order
And link to the spec
* RFC: add the shared anchor serialization rule test
Co-authored-by: teor <teor@riseup.net>
When we're naming the anchors without the corresponding type or struct,
it's not clear if they are shared or per spend.
Rename the fields as `shared_anchor` or `per_spend_anchor`.
* propose a v5 transaction rfc
* define orchard flags
* Update test sections
* Add security section
* move some code into sapling and orchard crates, do renames
* Move sapling value balance into shielded data
* Add AuthorizedAction type
* Order fields based on last serialized data
* Add the proofsOrchard field
* Delete visibility modifiers for readability
All those `pub`s make the design harder to read.
* Model anchor variants as generic trait types
* Be specific about the network upgrade
* Specify a file for each new type
* Document how the Orchard flags are used
Co-authored-by: teor <teor@riseup.net>
Alfredo Garcia
teor