librustzcash/zcash_client_backend/CHANGELOG.md

# Changelog
All notable changes to this library will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this library adheres to Rust's notion of
[Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [Unreleased]

### Added
- Functionality that enables the receiving and spending of transparent funds,
  behind the new `transparent-inputs` feature flag.
  - A new `data_api::wallet::shield_transparent_funds` method has been added
    to facilitate the automatic shielding of transparent funds received
    by the wallet.
  - A `zcash_client_backend::wallet::WalletTransparentOutput` type
    in support of `transparent-inputs` functionality.
- A new `data_api::wallet::spend` method has been added, which is
  intended to supersede the `data_api::wallet::create_spend_to_address`
  method. This new method now constructs transactions via interpretation
  of a `zcash_client_backend::zip321::TransactionRequest` value.
  This facilitates the implementation of ZIP 321 support in wallets and
  provides substantially greater flexibility in transaction creation.
- An `unstable` feature flag; this is added to parts of the API that may change
  in any release.
- `zcash_client_backend::address`:
  - `RecipientAddress::Unified`
  - `AddressMetadata`
- `zcash_client_backend::data_api`:
  - `PoolType`
  - `ShieldedPool`
  - `Recipient`
  - `SentTransactionOutput`
  - `WalletRead::get_unified_full_viewing_keys`
  - `WalletRead::get_account_for_ufvk`
  - `WalletRead::get_current_address`
  - `WalletRead::get_all_nullifiers`
  - `WalletRead::get_transparent_receivers`
  - `WalletRead::get_unspent_transparent_outputs`
  - `WalletRead::get_transparent_balances`
  - `WalletWrite::create_account`
  - `WalletWrite::remove_unmined_tx` (behind the `unstable` feature flag).
  - `WalletWrite::get_next_available_address`
  - `WalletWrite::put_received_transparent_utxo`
  - `impl From<prost::DecodeError> for error::Error`
  - `chain::error`: a module containing error types type that that can occur only
    in chain validation and sync have been separated out from errors related to
    other wallet operations.
  - `input_selection`: a module containing types related to the process
    of selecting inputs to be spent, given a transaction request.
- `zcash_client_backend::decrypt`:
  - `TransferType`
- `zcash_client_backend::proto`:
  - `actions` field on `compact_formats::CompactTx`
  - `compact_formats::CompactOrchardAction`
  - gRPC bindings for the `lightwalletd` server, behind a `lightwalletd-tonic`
    feature flag.
- `zcash_client_backend::zip321::TransactionRequest` methods:
  - `TransactionRequest::empty` for constructing a new empty request.
  - `TransactionRequest::new` for constructing a request from `Vec<Payment>`.
  - `TransactionRequest::payments` for accessing the `Payments` that make up a
    request.
- `zcash_client_backend::encoding`
  - `KeyError`
  - `AddressCodec` implementations for `sapling::PaymentAddress` and
    `UnifiedAddress`
- `zcash_client_backend::fees`
  - `ChangeError`
  - `ChangeStrategy`
  - `ChangeValue`
  - `TransactionBalance`
  - `BasicFixedFeeChangeStrategy` - a `ChangeStrategy` implementation that
    reproduces current wallet change behavior
  - `fixed` a new module containing of change selection strategies for the
    existing fixed fee rule.
- New experimental APIs that should be considered unstable, and are
  likely to be modified and/or moved to a different module in a future
  release:
  - `zcash_client_backend::address::UnifiedAddress`
  - `zcash_client_backend::keys::{UnifiedSpendingKey`, `UnifiedFullViewingKey`, `Era`, `DecodingError`}
  - `zcash_client_backend::encoding::AddressCodec`
  - `zcash_client_backend::encoding::encode_payment_address`
  - `zcash_client_backend::encoding::encode_transparent_address`
- `impl Eq for zcash_client_backend::address::UnifiedAddress`

### Changed
- MSRV is now 1.56.1.
- Bumped dependencies to `ff 0.12`, `group 0.12`, `bls12_381 0.7`, `jubjub 0.9`,
  `zcash_primitives 0.8`, `orchard 0.3`.
- `zcash_client_backend::proto`:
  - The Protocol Buffers bindings are now generated for `prost 0.11` instead of
    `protobuf 2`.
  - `compact_formats::CompactSpend` has been renamed to `CompactSaplingSpend`,
    and its `epk` field (and associated `set_epk` method) has been renamed to
    `ephemeralKey` (and `set_ephemeralKey`).
  - `compact_formats::CompactOutput` has been renamed to `CompactSaplingOutput`.
- `epk: jubjub::ExtendedPoint` has been replaced by
  `ephemeral_key: zcash_note_encryption::EphemeralKeyBytes` in various places:
  - `zcash_client_backend::wallet::WalletShieldedOutput`: the `epk` field has
    been replaced by `ephemeral_key`.
  - `zcash_client_backend::proto::compact_formats::CompactSaplingOutput`: the
    `epk` method has been replaced by `ephemeral_key`.
- Renamed the following in `zcash_client_backend::data_api` to use lower-case
  abbreviations (matching Rust naming conventions):
  - `testing::MockWalletDB` to `testing::MockWalletDb`
- Changes to the `data_api::WalletRead` trait:
  - `WalletRead::get_target_and_anchor_heights` now takes
    a `min_confirmations` argument that is used to compute an upper bound on
    the anchor height being returned; this had previously been hardcoded to
    `data_api::wallet::ANCHOR_OFFSET`.
  - `WalletRead::get_spendable_notes` has been renamed to
    `get_spendable_sapling_notes` and now takes as an argument a vector of
    note IDs to be excluded from consideration.
  - `WalletRead::select_spendable_notes` has been renamed to
    `select_spendable_sapling_notes` and now takes as an argument a vector of
    note IDs to be excluded from consideration.
  - The `WalletRead::NoteRef` and `WalletRead::TxRef` associated types are now
    required to implement `Eq` and `Ord`
- The `zcash_client_backend::data_api::SentTransaction` type has been
  substantially modified to accommodate handling of transparent inputs.
  Per-output data has been split out into a new struct `SentTransactionOutput`
  and `SentTransaction` can now contain multiple outputs, and tracks the
  fee paid.
- `data_api::WalletWrite::store_received_tx` has been renamed to
  `store_decrypted_tx`.
- `data_api::ReceivedTransaction` has been renamed to `DecryptedTransaction`,
  and its `outputs` field has been renamed to `sapling_outputs`.
- `data_api::error::Error` has been substantially modified. It now wraps database,
  note selection, builder, and other errors
  - `Error::DataSource` has been added.
  - `Error::NoteSelection` has been added.
  - `Error::BalanceError` has been added.
  - `Error::MemoForbidden` has been added.
  - `Error::AddressNotRecognized` has been added.
  - `Error::ChildIndexOutOfRange` has been added.
  - `Error::NoteMismatch` has been added.
  - `Error::InsufficientBalance` has been renamed `InsufficientFunds` and
    restructured to have named fields.
  - `Error::Protobuf` has been removed; these decoding errors are now
    produced as data source and/or block-source implementation-specific
    errors.
  - `Error::InvalidChain` has been removed; its former purpose is now served
    by `zcash_client_backend::data_api::chain::ChainError`.
  - `Error::InvalidNewWitnessAnchor` and `Error::InvalidWitnessAnchor` have
    been moved to `zcash_client_backend::data_api::chain::error::ContinuityError`
  - `Error::InvalidExtSk` (now unused) has been removed.
  - `Error::KeyNotFound` (now unused) has been removed.
  - `Error::KeyDerivationError` (now unused) has been removed.
  - `Error::SaplingNotActive` (now unused) has been removed.
- `zcash_client_backend::decrypt`:
  - `decrypt_transaction` now takes a `HashMap<_, UnifiedFullViewingKey>`
    instead of `HashMap<_, ExtendedFullViewingKey>`.
- If no memo is provided when sending to a shielded recipient, the
  empty memo will be used
- `zcash_client_backend::keys::spending_key` has been moved to the
  `zcash_client_backend::keys::sapling` module.
- `zcash_client_backend::zip321::MemoError` has been renamed and
  expanded into a more comprehensive `Zip321Error` type, and functions in the
  `zip321` module have been updated to use this unified error type. The
  following error cases have been added:
  - `Zip321Error::TooManyPayments(usize)`
  - `Zip321Error::DuplicateParameter(parse::Param, usize)`
  - `Zip321Error::TransparentMemo(usize)`
  - `Zip321Error::RecipientMissing(usize)`
  - `Zip321Error::ParseError(String)`
- The api of `welding_rig::ScanningKey` has changed to accommodate batch
  decryption and to correctly handle scanning with the internal (change) keys
  derived from ZIP 316 UFVKs and UIVKs.
- `welding_rig::scan_block` now uses batching for trial-decryption of
  transaction outputs.
- The return type of the following methods in `zcash_client_backend::encoding`
  have been changed to improve error reporting:
  - `decode_extended_spending_key`
  - `decode_extended_full_viewing_key`
  - `decode_payment_address`
- `zcash_client_backend::wallet::SpendableNote` is now parameterized by a note
  identifier type and has an additional `note_id` field that is used to hold the
  identifier used to refer to the note in the wallet database.
- `zcash_client_backend::data_api::BlockSource` has been moved to the
  `zcash_client_backend::data_api::chain` module.
- The types of the `with_row` callback argument to `BlockSource::with_blocks`
  and the return type of this method have been modified to return
  `zcash_client_backend::data_api::chain::error::Error`.
- `zcash_client_backend::data_api::testing::MockBlockSource` has been moved to
  `zcash_client_backend::data_api::chain::testing::MockBlockSource` module.
- `zcash_client_backend::data_api::chain::{validate_chain, scan_cached_blocks}`
  have altered parameters and result types. The latter have been modified to
  return`zcash_client_backend::data_api::chain::error::Error` instead of
  abstract error types. This new error type now wraps the errors of the block
  source and wallet database to which these methods delegate IO operations
  directly, which simplifies error handling in cases where callback functions
  are involved.
- `zcash_client_backend::data_api::error::ChainInvalid` has been moved to
  `zcash_client_backend::data_api::chain::error`.
- The error type of `zcash_client_backend::data_api::wallet::decrypt_and_store_transaction`
  has been changed; the error type produced by the provided `WalletWrite` instance is
  returned directly.

### Deprecated
- `zcash_client_backend::data_api::wallet::create_spend_to_address` has been
  deprecated. Use `zcash_client_backend::data_api::wallet::spend` instead. If
  you wish to continue using `create_spend_to_address`, note that the arguments
  to the function has been modified to take a unified spending key instead of a
  Sapling extended spending key, and now also requires a `min_confirmations`
  argument that the caller can provide to specify a minimum number of
  confirmations required for notes being selected. A minimum of 10
  confirmations is recommended.

### Removed
- `zcash_client_backend::data_api`:
  - `WalletRead::get_extended_full_viewing_keys` (use
    `WalletRead::get_unified_full_viewing_keys` instead).
  - `WalletRead::get_address` (use `WalletRead::get_current_address` or
    `WalletWrite::get_next_available_address` instead.)
  - `impl From<protobuf::ProtobufError> for error::Error`
- `zcash_client_backend::proto::compact_formats`:
  - `Compact*::new` methods (use `Default::default` or struct instantiation
    instead).
  - Getters (use dedicated typed methods or direct field access instead).
  - Setters (use direct field access instead).
- The hardcoded `data_api::wallet::ANCHOR_OFFSET` constant.
- `zcash_client_backend::wallet::AccountId` (moved to `zcash_primitives::zip32::AccountId`).
- The implementation of `welding_rig::ScanningKey` for `ExtendedFullViewingKey`
  has been removed. Use `DiversifiableFullViewingKey` instead.

## [0.5.0] - 2021-03-26
### Added
- `zcash_client_backend::address::RecipientAddress`
- `zcash_client_backend::data_api` module, containing the Data Access API.
- `zcash_client_backend::wallet`:
  - `AccountId`
  - `SpendableNote`
  - `OvkPolicy`
- `zcash_client_backend::welding_rig::ScanningKey` trait, representing a key
  which can be used for trial decryption of outputs, and optionally nullifier
  computation. This trait is implemented for
  `zcash_primitives::zip32:ExtendedFullViewingKey` and
  `zcash_primitives::primitives::SaplingIvk`.
- First alpha of TZE support, behind the `zfuture` feature flag.

### Changed
- MSRV is now 1.47.0.
- `epk` fields and return values were changed from a `jubjub::SubgroupPoint` to
  a `jubjub::ExtendedPoint`, to match the change to the `zcash_primitives`
  decryption APIs:
  - `zcash_client_backend::proto::compact_formats::CompactOutput::epk()`
  - The `epk` field of `zcash_client_backend::wallet::WalletShieldedOutput`.
- `zcash_client_backend::decrypt`:
  - `decrypt_transaction` now takes a variable with type
    `P: zcash_primitives::consensus::Parameters`.
  - The `memo` field of `DecryptedOutput` now has type `MemoBytes`.
- `zcash_client_backend::wallet`:
  - The `nf` property of `WalletShieldedSpend` now has the type `Nullifier`.
  - The `account` property of `WalletShieldedSpend` and `WalletShieldedOutput`
    now has the type `AccountId`.
- `zcash_client_backend::welding_rig`:
  - `scan_block` now takes `&[(AccountId, K: ScanningKey)]`, instead of a
    slice of extended full viewing keys with implicit account IDs.
  - The `nullifiers` argument to `scan_block` now has the type
    `&[(AccountId, Nullifier)]`.

### Removed
- `zcash_client_backend::constants` module (its sub-modules have been moved into
  `zcash_primitives::constants`, and more generally replaced by the new methods
  on the `zcash_primitives::consensus::Parameters` trait).

## [0.4.0] - 2020-09-09
### Changed
- MSRV is now 1.44.1.
- Bumped dependencies to `ff 0.8`, `group 0.8`, `bls12_381 0.3.1`,
  `jubjub 0.5.1`, `protobuf 2.15`.

## [0.3.0] - 2020-08-24
TBD

## [0.2.0] - 2020-03-13
TBD

## [0.1.0] - 2019-10-08
Initial release.