Blockstack

This is a hotfix release for improved handling of static analysis storage and
improved `at-block` behavior. The chainstate directory of 2.0.8 is compatible with
the 2.0.7 chainstate.

Fixed

- Improved static analysis storage
- `at-block` behavior in `clarity-cli` and unit tests (no changes in `stacks-node`
behavior).

This is an emergency hotfix that prevents the node from accidentally deleting
valid block data if its descendant microblock stream is invalid for some reason.

Fixed

- Do not delete a valid parent Stacks block.

working directory. Earlier versions' chainstate directories are
incompatible, however.

Fixed

- Miner RBF logic has two "fallback" logic changes. First, if the RBF
logic has increased fees by more than 50%, do not submit a new
transaction. Second, fix the "same chainstate hash" fallback check.
- Winning block txid lookups in the SortitionDB have been corrected
to use the txid during the lookup.
- The miner will no longer attempt to mine a new Stacks block if it receives a
microblock in a discontinuous microblock stream.

The database schema has changed since 2.0.4, so when spinning up a 2.0.5
node from an earlier chainstate, you must use a fresh working directory.

Added

- Miner heuristic for handling relatively large or computationally
expensive transactions: such transactions will be dropped from the
mempool to prevent miners from re-attempting them once they fail.
Miners can also now continue processing transactions that are
behind those transactions in the mempool "queue".

Fixed

- Miner block assembly now uses the correct block limit available via
the node config
- `tx_fees_streamed_produced` fees are included in miner coinbase
events for event observers
- SQLite indexes are now correctly created on database instantion

Changed

- STX unlock events are now sent over the events endpoint bundled
into an associated unlock transaction
- Atlas attachments networking endpoints are disabled for this
release, while networking issues are addressed in the
implementation

Changed

- Atlas attachments networking endpoints are disabled for this
release, while networking issues are addressed in the
implementation.

Added

- `stacks-node --mine-at-height` commandline option, which tells the
`stacks-node` not to mine until it has synchronized to the given
Stacks block height
- A new RPC endpoint `/v2/blocks/upload/{consensus_hash}` that accepts
an uploaded a Stacks block for a given sortition

Changed

- Enabled WAL mode for the chainstate databases. This allows much more
concurrency in the `stacks-node`, and improves network performance
across the board. **NOTE:** *This changed the database schema, any
running node would need to re-initialize their nodes from a new chain
state when upgrading*.
- Default value `wait_time_for_microblocks`: from 60s to 30s
- The mempool now performs more transfer semantics checks before admitting
a transaction (e.g., reject if origin = recipient): see issue 2354
- Improved the performance of the code that handles `GetBlocksInv` p2p
messages by an order of magnitude.
- Improved the performance of the block-downloader's block and
microblock search code by a factor of 5x.

Fixed

- Miner mempool querying now works across short-lived forks: see issue 2389
- JSON deserialization for high-depth JSON objects
- Atlas attachment serving: see PR 2390
- Address issues 2379, 2356, 2347, 2346. The tracking of the
`LeaderBlockCommit` operations inflight is improved, drastically
reducing the number of block commit rejections. When
a`LeaderBlockCommit` is not included in the Bitcoin block it was
targeting, it is condemned to be rejected, per the Stacks
consensus. To avoid wasting BTC, the miner now tries to send its
next `LeaderBlockCommit` operations using the UTXOs of the previous
transaction with a replacement by fee. The fee increase increments
can be configured with the setting `rbf_fee_increment`.