github.com/badrootd/nibiru-cometbft@v0.37.5-0.20240307173500-2a75559eee9b/spec/abci/abci++_methods.md (about) 1 --- 2 order: 2 3 title: Methods 4 --- 5 6 # Methods 7 8 ## Methods existing in ABCI 9 10 ### Echo 11 12 * **Request**: 13 * `Message (string)`: A string to echo back 14 * **Response**: 15 * `Message (string)`: The input string 16 * **Usage**: 17 * Echo a string to test an abci client/server implementation 18 19 ### Flush 20 21 * **Usage**: 22 * Signals that messages queued on the client should be flushed to 23 the server. It is called periodically by the client 24 implementation to ensure asynchronous requests are actually 25 sent, and is called immediately to make a synchronous request, 26 which returns when the Flush response comes back. 27 28 ### Info 29 30 * **Request**: 31 32 | Name | Type | Description | Field Number | 33 |---------------|--------|------------------------------------------|--------------| 34 | version | string | The CometBFT software semantic version | 1 | 35 | block_version | uint64 | The CometBFT Block Protocol version | 2 | 36 | p2p_version | uint64 | The CometBFT P2P Protocol version | 3 | 37 | abci_version | string | The CometBFT ABCI semantic version | 4 | 38 39 * **Response**: 40 41 | Name | Type | Description | Field Number | 42 |---------------------|--------|-----------------------------------------------------|--------------| 43 | data | string | Some arbitrary information | 1 | 44 | version | string | The application software semantic version | 2 | 45 | app_version | uint64 | The application protocol version | 3 | 46 | last_block_height | int64 | Latest height for which the app persisted its state | 4 | 47 | last_block_app_hash | bytes | Latest AppHash returned by `Commit` | 5 | 48 49 * **Usage**: 50 * Return information about the application state. 51 * Used to sync CometBFT with the application during a handshake 52 that happens on startup or on recovery. 53 * The returned `app_version` will be included in the Header of every block. 54 * CometBFT expects `last_block_app_hash` and `last_block_height` to 55 be updated and persisted during `Commit`. 56 57 > Note: Semantic version is a reference to [semantic versioning](https://semver.org/). Semantic versions in info will be displayed as X.X.x. 58 59 ### InitChain 60 61 * **Request**: 62 63 | Name | Type | Description | Field Number | 64 |------------------|-------------------------------------------------|-----------------------------------------------------|--------------| 65 | time | [google.protobuf.Timestamp][protobuf-timestamp] | Genesis time | 1 | 66 | chain_id | string | ID of the blockchain. | 2 | 67 | consensus_params | [ConsensusParams](#consensusparams) | Initial consensus-critical parameters. | 3 | 68 | validators | repeated [ValidatorUpdate](#validatorupdate) | Initial genesis validators, sorted by voting power. | 4 | 69 | app_state_bytes | bytes | Serialized initial application state. JSON bytes. | 5 | 70 | initial_height | int64 | Height of the initial block (typically `1`). | 6 | 71 72 * **Response**: 73 74 | Name | Type | Description | Field Number | 75 |------------------|----------------------------------------------|--------------------------------------------------|--------------| 76 | consensus_params | [ConsensusParams](#consensusparams) | Initial consensus-critical parameters (optional) | 1 | 77 | validators | repeated [ValidatorUpdate](#validatorupdate) | Initial validator set (optional). | 2 | 78 | app_hash | bytes | Initial application hash. | 3 | 79 80 * **Usage**: 81 * Called once upon genesis. 82 * If `ResponseInitChain.Validators` is empty, the initial validator set will be the `RequestInitChain.Validators` 83 * If `ResponseInitChain.Validators` is not empty, it will be the initial 84 validator set (regardless of what is in `RequestInitChain.Validators`). 85 * This allows the app to decide if it wants to accept the initial validator 86 set proposed by CometBFT (ie. in the genesis file), or if it wants to use 87 a different one (perhaps computed based on some application specific 88 information in the genesis file). 89 * Both `RequestInitChain.Validators` and `ResponseInitChain.Validators` are [ValidatorUpdate](#validatorupdate) structs. 90 So, technically, they both are _updating_ the set of validators from the empty set. 91 92 ### Query 93 94 * **Request**: 95 96 | Name | Type | Description | Field Number | 97 |--------|--------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------| 98 | data | bytes | Raw query bytes. Can be used with or in lieu of Path. | 1 | 99 | path | string | Path field of the request URI. Can be used with or in lieu of `data`. Apps MUST interpret `/store` as a query by key on the underlying store. The key SHOULD be specified in the `data` field. Apps SHOULD allow queries over specific types like `/accounts/...` or `/votes/...` | 2 | 100 | height | int64 | The block height for which you want the query (default=0 returns data for the latest committed block). Note that this is the height of the block containing the application's Merkle root hash, which represents the state as it was after committing the block at Height-1 | 3 | 101 | prove | bool | Return Merkle proof with response if possible | 4 | 102 103 * **Response**: 104 105 | Name | Type | Description | Field Number | 106 |-----------|-----------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------| 107 | code | uint32 | Response code. | 1 | 108 | log | string | The output of the application's logger. **May be non-deterministic.** | 3 | 109 | info | string | Additional information. **May be non-deterministic.** | 4 | 110 | index | int64 | The index of the key in the tree. | 5 | 111 | key | bytes | The key of the matching data. | 6 | 112 | value | bytes | The value of the matching data. | 7 | 113 | proof_ops | [ProofOps](#proofops) | Serialized proof for the value data, if requested, to be verified against the `app_hash` for the given Height. | 8 | 114 | height | int64 | The block height from which data was derived. Note that this is the height of the block containing the application's Merkle root hash, which represents the state as it was after committing the block at Height-1 | 9 | 115 | codespace | string | Namespace for the `code`. | 10 | 116 117 * **Usage**: 118 * Query for data from the application at current or past height. 119 * Optionally return Merkle proof. 120 * Merkle proof includes self-describing `type` field to support many types 121 of Merkle trees and encoding formats. 122 123 ### CheckTx 124 125 * **Request**: 126 127 | Name | Type | Description | Field Number | 128 |------|-------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------| 129 | tx | bytes | The request transaction bytes | 1 | 130 | type | CheckTxType | One of `CheckTx_New` or `CheckTx_Recheck`. `CheckTx_New` is the default and means that a full check of the tranasaction is required. `CheckTx_Recheck` types are used when the mempool is initiating a normal recheck of a transaction. | 2 | 131 132 * **Response**: 133 134 | Name | Type | Description | Field Number | 135 |------------|-------------------------------------------------------------|-----------------------------------------------------------------------|--------------| 136 | code | uint32 | Response code. | 1 | 137 | data | bytes | Result bytes, if any. | 2 | 138 | gas_wanted | int64 | Amount of gas requested for transaction. | 5 | 139 | codespace | string | Namespace for the `code`. | 8 | 140 | sender | string | The transaction's sender (e.g. the signer) | 9 | 141 | priority | int64 | The transaction's priority (for mempool ordering) | 10 | 142 143 * **Usage**: 144 145 * Technically optional - not involved in processing blocks. 146 * Guardian of the mempool: every node runs `CheckTx` before letting a 147 transaction into its local mempool. 148 * The transaction may come from an external user or another node 149 * `CheckTx` validates the transaction against the current state of the application, 150 for example, checking signatures and account balances, but does not apply any 151 of the state changes described in the transaction. 152 * Transactions where `ResponseCheckTx.Code != 0` will be rejected - they will not be broadcast 153 to other nodes or included in a proposal block. 154 CometBFT attributes no other value to the response code. 155 156 ### BeginBlock 157 158 * **Request**: 159 160 | Name | Type | Description | Field Number | 161 |----------------------|---------------------------------------------|-------------------------------------------------------------------------------------------------------------------|--------------| 162 | hash | bytes | The block's hash. This can be derived from the block header. | 1 | 163 | header | [Header](../core/data_structures.md#header) | The block header. | 2 | 164 | last_commit_info | [CommitInfo](#commitinfo) | Info about the last commit, including the round, and the list of validators and which ones signed the last block. | 3 | 165 | byzantine_validators | repeated [Evidence](abci++_basic_concepts.md#evidence) | List of evidence of validators that acted maliciously. | 4 | 166 167 * **Response**: 168 169 | Name | Type | Description | Field Number | 170 |--------|---------------------------|-------------------------------------|--------------| 171 | events | repeated [Event](abci++_basic_concepts.md#events) | type & Key-Value events for indexing | 1 | 172 173 * **Usage**: 174 * Signals the beginning of a new block. 175 * Called prior to any `DeliverTx` method calls. 176 * The header contains the height, timestamp, and more - it exactly matches the 177 CometBFT block header. We may seek to generalize this in the future. 178 * The `CommitInfo` and `ByzantineValidators` can be used to determine 179 rewards and punishments for the validators. 180 181 ### DeliverTx 182 183 * **Request**: 184 185 | Name | Type | Description | Field Number | 186 |------|-------|--------------------------------|--------------| 187 | tx | bytes | The request transaction bytes. | 1 | 188 189 * **Response**: 190 191 | Name | Type | Description | Field Number | 192 |------------|---------------------------|-----------------------------------------------------------------------|--------------| 193 | code | uint32 | Response code. | 1 | 194 | data | bytes | Result bytes, if any. | 2 | 195 | log | string | The output of the application's logger. **May be non-deterministic.** | 3 | 196 | info | string | Additional information. **May be non-deterministic.** | 4 | 197 | gas_wanted | int64 | Amount of gas requested for transaction. | 5 | 198 | gas_used | int64 | Amount of gas consumed by transaction. | 6 | 199 | events | repeated [Event](abci++_basic_concepts.md#events) | Type & Key-Value events for indexing transactions (eg. by account). | 7 | 200 | codespace | string | Namespace for the `code`. | 8 | 201 202 * **Usage**: 203 * [**Required**] The core method of the application. 204 * `DeliverTx` is called once for each transaction in the block. 205 * When `DeliverTx` is called, the application must execute the transaction deterministically 206 in full before returning control to CometBFT. 207 * Alternatively, the application can apply a candidate state corresponding 208 to the same block previously executed via `PrepareProposal` or `ProcessProposal` any time between the calls to `BeginBlock`, the various 209 calls to `DeliverTx` and `EndBlock`. 210 * `ResponseDeliverTx.Code == 0` only if the transaction is fully valid. 211 212 213 ### EndBlock 214 215 * **Request**: 216 217 | Name | Type | Description | Field Number | 218 |--------|-------|------------------------------------|--------------| 219 | height | int64 | Height of the block just executed. | 1 | 220 221 * **Response**: 222 223 | Name | Type | Description | Field Number | 224 |-------------------------|----------------------------------------------|-----------------------------------------------------------------|--------------| 225 | validator_updates | repeated [ValidatorUpdate](#validatorupdate) | Changes to validator set (set voting power to 0 to remove). | 1 | 226 | consensus_param_updates | [ConsensusParams](#consensusparams) | Changes to consensus-critical time, size, and other parameters. | 2 | 227 | events | repeated [Event](abci++_basic_concepts.md#events) | Type & Key-Value events for indexing | 3 | 228 229 * **Usage**: 230 * Signals the end of a block. 231 * Called after all the transactions for the current block have been delivered, prior to the block's `Commit` message. 232 * Optional `validator_updates` triggered by block `H`. These updates affect validation 233 for blocks `H+1`, `H+2`, and `H+3`. 234 * Heights following a validator update are affected in the following way: 235 * `H+1`: `NextValidatorsHash` includes the new `validator_updates` value. 236 * `H+2`: The validator set change takes effect and `ValidatorsHash` is updated. 237 * `H+3`: `last_commit_info (BeginBlock)` is changed to include the altered validator set and `*_last_commit` fields in `PrepareProposal`, `ProcessProposal` now include the altered validator set. 238 * `consensus_param_updates` returned for block `H` apply to the consensus 239 params for block `H+1`. For more information on the consensus parameters, 240 see the [application spec entry on consensus parameters](./abci++_app_requirements.md#consensus-parameters). 241 * `validator_updates` and `consensus_param_updates` may be empty. In this case, CometBFT will keep the current values. 242 243 244 245 ### Commit 246 247 * **Request**: 248 249 | Name | Type | Description | Field Number | 250 |--------|-------|------------------------------------|--------------| 251 252 Commit signals the application to persist application state. It takes no parameters. 253 * **Response**: 254 255 | Name | Type | Description | Field Number | 256 |---------------|-------|------------------------------------------------------------------------|--------------| 257 | data | bytes | The Merkle root hash of the application state. | 2 | 258 | retain_height | int64 | Blocks below this height may be removed. Defaults to `0` (retain all). | 3 | 259 260 * **Usage**: 261 * Signal the application to persist the application state. 262 * Return an (optional) Merkle root hash of the application state 263 * `ResponseCommit.Data` is included as the `Header.AppHash` in the next block 264 * It may be empty or hard-coded, but MUST be **deterministic** - it must not be a function of anything that did not come from the parameters of the execution calls (`BeginBlock/DeliverTx/EndBlock methods`) and the previous committed state. 265 * Later calls to `Query` can return proofs about the application state anchored 266 in this Merkle root hash 267 * Use `RetainHeight` with caution! If all nodes in the network remove historical 268 blocks then this data is permanently lost, and no new nodes will be able to 269 join the network and bootstrap. Historical blocks may also be required for 270 other purposes, e.g. auditing, replay of non-persisted heights, light client 271 verification, and so on. 272 273 ### ListSnapshots 274 275 * **Request**: 276 277 | Name | Type | Description | Field Number | 278 |--------|-------|------------------------------------|--------------| 279 280 Empty request asking the application for a list of snapshots. 281 282 * **Response**: 283 284 | Name | Type | Description | Field Number | 285 |-----------|--------------------------------|--------------------------------|--------------| 286 | snapshots | repeated [Snapshot](#snapshot) | List of local state snapshots. | 1 | 287 288 * **Usage**: 289 * Used during state sync to discover available snapshots on peers. 290 * See `Snapshot` data type for details. 291 292 ### LoadSnapshotChunk 293 294 * **Request**: 295 296 | Name | Type | Description | Field Number | 297 |--------|--------|-----------------------------------------------------------------------|--------------| 298 | height | uint64 | The height of the snapshot the chunk belongs to. | 1 | 299 | format | uint32 | The application-specific format of the snapshot the chunk belongs to. | 2 | 300 | chunk | uint32 | The chunk index, starting from `0` for the initial chunk. | 3 | 301 302 * **Response**: 303 304 | Name | Type | Description | Field Number | 305 |-------|-------|-------------------------------------------------------------------------------------------------------------------------------------------------------|--------------| 306 | chunk | bytes | The binary chunk contents, in an arbitray format. Chunk messages cannot be larger than 16 MB _including metadata_, so 10 MB is a good starting point. | 1 | 307 308 * **Usage**: 309 * Used during state sync to retrieve snapshot chunks from peers. 310 311 ### OfferSnapshot 312 313 * **Request**: 314 315 | Name | Type | Description | Field Number | 316 |----------|-----------------------|--------------------------------------------------------------------------|--------------| 317 | snapshot | [Snapshot](#snapshot) | The snapshot offered for restoration. | 1 | 318 | app_hash | bytes | The light client-verified app hash for this height, from the blockchain. | 2 | 319 320 * **Response**: 321 322 | Name | Type | Description | Field Number | 323 |--------|-------------------|-----------------------------------|--------------| 324 | result | [Result](#result) | The result of the snapshot offer. | 1 | 325 326 #### Result 327 328 ```protobuf 329 enum Result { 330 UNKNOWN = 0; // Unknown result, abort all snapshot restoration 331 ACCEPT = 1; // Snapshot is accepted, start applying chunks. 332 ABORT = 2; // Abort snapshot restoration, and don't try any other snapshots. 333 REJECT = 3; // Reject this specific snapshot, try others. 334 REJECT_FORMAT = 4; // Reject all snapshots with this `format`, try others. 335 REJECT_SENDER = 5; // Reject all snapshots from all senders of this snapshot, try others. 336 } 337 ``` 338 339 * **Usage**: 340 * `OfferSnapshot` is called when bootstrapping a node using state sync. The application may 341 accept or reject snapshots as appropriate. Upon accepting, CometBFT will retrieve and 342 apply snapshot chunks via `ApplySnapshotChunk`. The application may also choose to reject a 343 snapshot in the chunk response, in which case it should be prepared to accept further 344 `OfferSnapshot` calls. 345 * Only `AppHash` can be trusted, as it has been verified by the light client. Any other data 346 can be spoofed by adversaries, so applications should employ additional verification schemes 347 to avoid denial-of-service attacks. The verified `AppHash` is automatically checked against 348 the restored application at the end of snapshot restoration. 349 * For more information, see the `Snapshot` data type or the [state sync section](../p2p/legacy-docs/messages/state-sync.md). 350 351 ### ApplySnapshotChunk 352 353 * **Request**: 354 355 | Name | Type | Description | Field Number | 356 |--------|--------|-----------------------------------------------------------------------------|--------------| 357 | index | uint32 | The chunk index, starting from `0`. CometBFT applies chunks sequentially. | 1 | 358 | chunk | bytes | The binary chunk contents, as returned by `LoadSnapshotChunk`. | 2 | 359 | sender | string | The P2P ID of the node who sent this chunk. | 3 | 360 361 * **Response**: 362 363 | Name | Type | Description | Field Number | 364 |----------------|---------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------| 365 | result | Result (see below) | The result of applying this chunk. | 1 | 366 | refetch_chunks | repeated uint32 | Refetch and reapply the given chunks, regardless of `result`. Only the listed chunks will be refetched, and reapplied in sequential order. | 2 | 367 | reject_senders | repeated string | Reject the given P2P senders, regardless of `Result`. Any chunks already applied will not be refetched unless explicitly requested, but queued chunks from these senders will be discarded, and new chunks or other snapshots rejected. | 3 | 368 369 ```proto 370 enum Result { 371 UNKNOWN = 0; // Unknown result, abort all snapshot restoration 372 ACCEPT = 1; // The chunk was accepted. 373 ABORT = 2; // Abort snapshot restoration, and don't try any other snapshots. 374 RETRY = 3; // Reapply this chunk, combine with `RefetchChunks` and `RejectSenders` as appropriate. 375 RETRY_SNAPSHOT = 4; // Restart this snapshot from `OfferSnapshot`, reusing chunks unless instructed otherwise. 376 REJECT_SNAPSHOT = 5; // Reject this snapshot, try a different one. 377 } 378 ``` 379 380 * **Usage**: 381 * The application can choose to refetch chunks and/or ban P2P peers as appropriate. CometBFT 382 will not do this unless instructed by the application. 383 * The application may want to verify each chunk, e.g. by attaching chunk hashes in 384 `Snapshot.Metadata` and/or incrementally verifying contents against `AppHash`. 385 * When all chunks have been accepted, CometBFT will make an ABCI `Info` call to verify that 386 `LastBlockAppHash` and `LastBlockHeight` matches the expected values, and record the 387 `AppVersion` in the node state. It then switches to block sync or consensus and joins the 388 network. 389 * If CometBFT is unable to retrieve the next chunk after some time (e.g. because no suitable 390 peers are available), it will reject the snapshot and try a different one via `OfferSnapshot`. 391 The application should be prepared to reset and accept it or abort as appropriate. 392 393 ## New methods introduced in ABCI 2.0 394 395 ### PrepareProposal 396 397 #### Parameters and Types 398 399 * **Request**: 400 401 | Name | Type | Description | Field Number | 402 |----------------------|-------------------------------------------------|-----------------------------------------------------------------------------------------------|--------------| 403 | max_tx_bytes | int64 | Currently configured maximum size in bytes taken by the modified transactions. | 1 | 404 | txs | repeated bytes | Preliminary list of transactions that have been picked as part of the block to propose. | 2 | 405 | local_last_commit | [ExtendedCommitInfo](#extendedcommitinfo) | Info about the last commit, obtained locally from CometBFT's data structures. | 3 | 406 | misbehavior | repeated [Misbehavior](#misbehavior) | List of information about validators that misbehaved. | 4 | 407 | height | int64 | The height of the block that will be proposed. | 5 | 408 | time | [google.protobuf.Timestamp][protobuf-timestamp] | Timestamp of the block that that will be proposed. | 6 | 409 | next_validators_hash | bytes | Merkle root of the next validator set. | 7 | 410 | proposer_address | bytes | [Address](../core/data_structures.md#address) of the validator that is creating the proposal. | 8 | 411 412 * **Response**: 413 414 | Name | Type | Description | Field Number | 415 |-------------------------|--------------------------------------------------|---------------------------------------------------------------------------------------------|--------------| 416 | txs | repeated bytes | Possibly modified list of transactions that have been picked as part of the proposed block. | 2 | 417 418 * **Usage**: 419 * `RequestPrepareProposal`'s parameters `txs`, `misbehavior`, `height`, `time`, 420 `next_validators_hash`, and `proposer_address` are the same as in `RequestProcessProposal`. 421 * `RequestPrepareProposal.local_last_commit` is a set of the precommit votes that allowed the 422 decision of the previous block. 423 * Fields `height`, `time`, `proposer_address`, and `next_validators_hash` match the values from 424 the header of the proposed block. 425 * `RequestPrepareProposal` contains a preliminary set of transactions `txs` that CometBFT 426 retrieved from the mempool, called _raw proposal_. The Application can modify this 427 set and return a modified set of transactions via `ResponsePrepareProposal.txs` . 428 * The Application _can_ modify the raw proposal: it can reorder, remove or add transactions. 429 Let `tx` be a transaction in `txs` (set of transactions within `RequestPrepareProposal`): 430 * If the Application considers that `tx` should not be proposed in this block, e.g., 431 there are other transactions with higher priority, then it should not include it in 432 `ResponsePrepareProposal.txs`. However, this will not remove `tx` from the mempool. 433 * If the Application wants to add a new transaction to the proposed block, then the 434 Application includes it in `ResponsePrepareProposal.txs`. CometBFT will not add 435 the transaction to the mempool. 436 * The Application should be aware that removing and adding transactions may compromise 437 _traceability_. 438 > Consider the following example: the Application transforms a client-submitted 439 transaction `t1` into a second transaction `t2`, i.e., the Application asks CometBFT 440 to remove `t1` from the block and add `t2` to the block. If a client wants to eventually check what 441 happened to `t1`, it will discover that `t1` is not in a 442 committed block (assuming a _re-CheckTx_ evited it from the mempool), getting the wrong idea that `t1` did not make it into a block. Note 443 that `t2` _will be_ in a committed block, but unless the Application tracks this 444 information, no component will be aware of it. Thus, if the Application wants 445 traceability, it is its responsability to support it. For instance, the Application 446 could attach to a transformed transaction a list with the hashes of the transactions it 447 derives from. 448 * CometBFT MAY include a list of transactions in `RequestPrepareProposal.txs` whose total 449 size in bytes exceeds `RequestPrepareProposal.max_tx_bytes`. 450 Therefore, if the size of `RequestPrepareProposal.txs` is greater than 451 `RequestPrepareProposal.max_tx_bytes`, the Application MUST remove transactions to ensure 452 that the `RequestPrepareProposal.max_tx_bytes` limit is respected by those transactions 453 returned in `ResponsePrepareProposal.txs` . 454 * As a result of executing the prepared proposal, the Application may produce block events or transaction events. 455 The Application must keep those events until a block is decided. It will then forward the events to the `BeginBlock-DeliverTx-EndBlock` functions depending on where each event should be placed, thereby returning the events to CometBFT. 456 * CometBFT does NOT provide any additional validity checks (such as checking for duplicate 457 transactions). 458 <!-- 459 As a sanity check, CometBFT will check the returned parameters for validity if the Application modified them. 460 In particular, `ResponsePrepareProposal.txs` will be deemed invalid if there are duplicate transactions in the list. 461 --> 462 * If CometBFT fails to validate the `ResponsePrepareProposal`, CometBFT will assume the 463 Application is faulty and crash. 464 * The implementation of `PrepareProposal` can be non-deterministic. 465 466 467 #### When does CometBFT call `PrepareProposal` ? 468 469 470 When a validator _p_ enters consensus round _r_, height _h_, in which _p_ is the proposer, 471 and _p_'s _validValue_ is `nil`: 472 473 1. CometBFT collects outstanding transactions from _p_'s mempool 474 * the transactions will be collected in order of priority 475 * _p_'s CometBFT creates a block header. 476 2. _p_'s CometBFT calls `RequestPrepareProposal` with the newly generated block, the local 477 commit of the previous height (with vote extensions), and any outstanding evidence of 478 misbehavior. The call is synchronous: CometBFT's execution will block until the Application 479 returns from the call. 480 3. The Application uses the information received (transactions, commit info, misbehavior, time) to 481 (potentially) modify the proposal. 482 * the Application MAY fully execute the block and produce a candidate state (immediate execution) 483 * the Application can manipulate transactions: 484 * leave transactions untouched 485 * add new transactions (not present initially) to the proposal 486 * remove transactions from the proposal (but not from the mempool thus effectively _delaying_ them) - the 487 Application does not include the transaction in `ResponsePrepareProposal.txs`. 488 * modify transactions (e.g. aggregate them). As explained above, this compromises client traceability, unless 489 it is implemented at the Application level. 490 * reorder transactions - the Application reorders transactions in the list 491 4. The Application includes the transaction list (whether modified or not) in the return parameters 492 (see the rules in section _Usage_), and returns from the call. 493 5. _p_ uses the (possibly) modified block as _p_'s proposal in round _r_, height _h_. 494 495 Note that, if _p_ has a non-`nil` _validValue_ in round _r_, height _h_, 496 the consensus algorithm will use it as proposal and will not call `RequestPrepareProposal`. 497 498 ### ProcessProposal 499 500 #### Parameters and Types 501 502 * **Request**: 503 504 | Name | Type | Description | Field Number | 505 |----------------------|-------------------------------------------------|-------------------------------------------------------------------------------------------|--------------| 506 | txs | repeated bytes | List of transactions of the proposed block. | 1 | 507 | proposed_last_commit | [CommitInfo](#commitinfo) | Info about the last commit, obtained from the information in the proposed block. | 2 | 508 | misbehavior | repeated [Misbehavior](#misbehavior) | List of information about validators that misbehaved. | 3 | 509 | hash | bytes | The hash of the proposed block. | 4 | 510 | height | int64 | The height of the proposed block. | 5 | 511 | time | [google.protobuf.Timestamp][protobuf-timestamp] | Timestamp of the proposed block. | 6 | 512 | next_validators_hash | bytes | Merkle root of the next validator set. | 7 | 513 | proposer_address | bytes | [Address](../core/data_structures.md#address) of the validator that created the proposal. | 8 | 514 515 * **Response**: 516 517 | Name | Type | Description | Field Number | 518 |-------------------------|--------------------------------------------------|-----------------------------------------------------------------------------------|--------------| 519 | status | [ProposalStatus](#proposalstatus) | `enum` that signals if the application finds the proposal valid. | 1 | 520 521 * **Usage**: 522 * Contains all information on the proposed block needed to fully execute it. 523 * The Application may fully execute the block as though it was handling the calls to `BeginBlock-DeliverTx-EndBlock`. 524 * However, any resulting state changes must be kept as _candidate state_, 525 and the Application should be ready to discard it in case another block is decided. 526 * `RequestProcessProposal` is also called at the proposer of a round. 527 Normally the call to `RequestProcessProposal` occurs right after the call to `RequestPrepareProposal` and 528 `RequestProcessProposal` matches the block produced based on `ResponsePrepareProposal` (i.e., 529 `RequestPrepareProposal.txs` equals `RequestProcessProposal.txs`). 530 However, no such guarantee is made since, in the presence of failures, `RequestProcessProposal` may match 531 `ResponsePrepareProposal` from an earlier invocation or `ProcessProposal` may not be invoked at all. 532 * The height and time values match the values from the header of the proposed block. 533 * If `ResponseProcessProposal.status` is `REJECT`, consensus assumes the proposal received 534 is not valid. 535 * The Application MAY fully execute the block — immediate execution 536 * The implementation of `ProcessProposal` MUST be deterministic. Moreover, the value of 537 `ResponseProcessProposal.status` MUST **exclusively** depend on the parameters passed in 538 the call to `RequestProcessProposal`, and the last committed Application state 539 (see [Requirements](./abci++_app_requirements.md) section). 540 * Moreover, application implementors SHOULD always set `ResponseProcessProposal.status` to `ACCEPT`, 541 unless they _really_ know what the potential liveness implications of returning `REJECT` are. 542 543 #### When does CometBFT call `ProcessProposal` ? 544 545 When a node _p_ enters consensus round _r_, height _h_, in which _q_ is the proposer (possibly _p_ = _q_): 546 547 1. _p_ sets up timer `ProposeTimeout`. 548 2. If _p_ is the proposer, _p_ executes steps 1-6 in [PrepareProposal](#prepareproposal). 549 3. Upon reception of Proposal message (which contains the header) for round _r_, height _h_ from 550 _q_, _p_ verifies the block header. 551 4. Upon reception of Proposal message, along with all the block parts, for round _r_, height _h_ 552 from _q_, _p_ follows the validators' algorithm to check whether it should prevote for the 553 proposed block, or `nil`. 554 5. If the validators' consensus algorithm indicates _p_ should prevote non-nil: 555 1. CometBFT calls `RequestProcessProposal` with the block. The call is synchronous. 556 2. The Application checks/processes the proposed block, which is read-only, and returns 557 `ACCEPT` or `REJECT` in the `ResponseProcessProposal.status` field. 558 * The Application, depending on its needs, may call `ResponseProcessProposal` 559 * either after it has completely processed the block (immediate execution), 560 * or after doing some basic checks, and process the block asynchronously. In this case the 561 Application will not be able to reject the block, or force prevote/precommit `nil` 562 afterwards. 563 * or immediately, returning `ACCEPT`, if _p_ is not a validator 564 and the Application does not want non-validating nodes to handle `ProcessProposal` 565 3. If _p_ is a validator and the returned value is 566 * `ACCEPT`: _p_ prevotes on this proposal for round _r_, height _h_. 567 * `REJECT`: _p_ prevotes `nil`. 568 569 <!-- 570 571 ### ExtendVote 572 573 #### Parameters and Types 574 575 * **Request**: 576 577 | Name | Type | Description | Field Number | 578 |--------|-------|-------------------------------------------------------------------------------|--------------| 579 | hash | bytes | The header hash of the proposed block that the vote extension is to refer to. | 1 | 580 | height | int64 | Height of the proposed block (for sanity check). | 2 | 581 582 * **Response**: 583 584 | Name | Type | Description | Field Number | 585 |-------------------|-------|---------------------------------------------------------|--------------| 586 | vote_extension | bytes | Information signed by by CometBFT. Can have 0 length. | 1 | 587 588 * **Usage**: 589 * `ResponseExtendVote.vote_extension` is application-generated information that will be signed 590 by CometBFT and attached to the Precommit message. 591 * The Application may choose to use an empty vote extension (0 length). 592 * `RequestExtendVote.hash` corresponds to the hash of a proposed block that was made available 593 to the Application in a previous call to `ProcessProposal` for the current height. 594 * `ResponseExtendVote.vote_extension` will only be attached to a non-`nil` Precommit message. If the consensus algorithm is to 595 precommit `nil`, it will not call `RequestExtendVote`. 596 * The Application logic that creates the extension can be non-deterministic. 597 598 #### When does CometBFT call `ExtendVote`? 599 600 When a validator _p_ is in consensus state _prevote_ of round _r_, height _h_, in which _q_ is the proposer; and _p_ has received 601 602 * the Proposal message _v_ for round _r_, height _h_, along with all the block parts, from _q_, 603 * `Prevote` messages from _2f + 1_ validators' voting power for round _r_, height _h_, prevoting for the same block _id(v)_, 604 605 then _p_ locks _v_ and sends a Precommit message in the following way 606 607 1. _p_ sets _lockedValue_ and _validValue_ to _v_, and sets _lockedRound_ and _validRound_ to _r_ 608 2. _p_'s CometBFT calls `RequestExtendVote` with _id(v)_ (`RequestExtendVote.hash`). The call is synchronous. 609 3. The Application returns an array of bytes, `ResponseExtendVote.extension`, which is not interpreted by the consensus algorithm. 610 4. _p_ includes `ResponseExtendVote.extension` in a field of type [CanonicalVoteExtension](#canonicalvoteextension), 611 it then populates the other fields in [CanonicalVoteExtension](#canonicalvoteextension), and signs the populated 612 data structure. 613 5. _p_ constructs and signs the [CanonicalVote](../core/data_structures.md#canonicalvote) structure. 614 6. _p_ constructs the Precommit message (i.e. [Vote](../core/data_structures.md#vote) structure) 615 using [CanonicalVoteExtension](#canonicalvoteextension) and [CanonicalVote](../core/data_structures.md#canonicalvote). 616 7. _p_ broadcasts the Precommit message. 617 618 In the cases when _p_ is to broadcast `precommit nil` messages (either _2f+1_ `prevote nil` messages received, 619 or _timeoutPrevote_ triggered), _p_'s CometBFT does **not** call `RequestExtendVote` and will not include 620 a [CanonicalVoteExtension](#canonicalvoteextension) field in the `precommit nil` message. 621 622 ### VerifyVoteExtension 623 624 #### Parameters and Types 625 626 * **Request**: 627 628 | Name | Type | Description | Field Number | 629 |-------------------|-------|-------------------------------------------------------------------------------------------|--------------| 630 | hash | bytes | The hash of the proposed block that the vote extension refers to. | 1 | 631 | validator_address | bytes | [Address](../core/data_structures.md#address) of the validator that signed the extension. | 2 | 632 | height | int64 | Height of the block (for sanity check). | 3 | 633 | vote_extension | bytes | Application-specific information signed by CometBFT. Can have 0 length. | 4 | 634 635 * **Response**: 636 637 | Name | Type | Description | Field Number | 638 |--------|-------------------------------|----------------------------------------------------------------|--------------| 639 | status | [VerifyStatus](#verifystatus) | `enum` signaling if the application accepts the vote extension | 1 | 640 641 * **Usage**: 642 * `RequestVerifyVoteExtension.vote_extension` can be an empty byte array. The Application's 643 interpretation of it should be 644 that the Application running at the process that sent the vote chose not to extend it. 645 CometBFT will always call `RequestVerifyVoteExtension`, even for 0 length vote extensions. 646 * `RequestVerifyVoteExtension` is not called for precommit votes sent by the local process. 647 * `RequestVerifyVoteExtension.hash` refers to a proposed block. There is not guarantee that 648 this proposed block has previously been exposed to the Application via `ProcessProposal`. 649 * If `ResponseVerifyVoteExtension.status` is `REJECT`, the consensus algorithm will reject the whole received vote. 650 See the [Requirements](./abci++_app_requirements.md) section to understand the potential 651 liveness implications of this. 652 * The implementation of `VerifyVoteExtension` MUST be deterministic. Moreover, the value of 653 `ResponseVerifyVoteExtension.status` MUST **exclusively** depend on the parameters passed in 654 the call to `RequestVerifyVoteExtension`, and the last committed Application state 655 (see [Requirements](./abci++_app_requirements.md) section). 656 * Moreover, application implementers SHOULD always set `ResponseVerifyVoteExtension.status` to `ACCEPT`, 657 unless they _really_ know what the potential liveness implications of returning `REJECT` are. 658 659 #### When does CometBFT call `VerifyVoteExtension`? 660 661 When a node _p_ is in consensus round _r_, height _h_, and _p_ receives a Precommit 662 message for round _r_, height _h_ from validator _q_ (_q_ ≠ _p_): 663 664 1. If the Precommit message does not contain a vote extension with a valid signature, _p_ 665 discards the Precommit message as invalid. 666 * a 0-length vote extension is valid as long as its accompanying signature is also valid. 667 2. Else, _p_'s CometBFT calls `RequestVerifyVoteExtension`. 668 3. The Application returns `ACCEPT` or `REJECT` via `ResponseVerifyVoteExtension.status`. 669 4. If the Application returns 670 * `ACCEPT`, _p_ will keep the received vote, together with its corresponding 671 vote extension in its internal data structures. It will be used to populate the [ExtendedCommitInfo](#extendedcommitinfo) 672 structure in calls to `RequestPrepareProposal`, in rounds of height _h + 1_ where _p_ is the proposer. 673 * `REJECT`, _p_ will deem the Precommit message invalid and discard it. 674 675 ### FinalizeBlock 676 677 #### Parameters and Types 678 679 * **Request**: 680 681 | Name | Type | Description | Field Number | 682 |----------------------|-------------------------------------------------|-------------------------------------------------------------------------------------------|--------------| 683 | txs | repeated bytes | List of transactions committed as part of the block. | 1 | 684 | decided_last_commit | [CommitInfo](#commitinfo) | Info about the last commit, obtained from the block that was just decided. | 2 | 685 | misbehavior | repeated [Misbehavior](#misbehavior) | List of information about validators that misbehaved. | 3 | 686 | hash | bytes | The block's hash. | 4 | 687 | height | int64 | The height of the finalized block. | 5 | 688 | time | [google.protobuf.Timestamp][protobuf-timestamp] | Timestamp of the finalized block. | 6 | 689 | next_validators_hash | bytes | Merkle root of the next validator set. | 7 | 690 | proposer_address | bytes | [Address](../core/data_structures.md#address) of the validator that created the proposal. | 8 | 691 692 * **Response**: 693 694 | Name | Type | Description | Field Number | 695 |-------------------------|-------------------------------------------------------------|----------------------------------------------------------------------------------|--------------| 696 | events | repeated [Event](abci++_basic_concepts.md#events) | Type & Key-Value events for indexing | 1 | 697 | tx_results | repeated [ExecTxResult](#exectxresult) | List of structures containing the data resulting from executing the transactions | 2 | 698 | validator_updates | repeated [ValidatorUpdate](#validatorupdate) | Changes to validator set (set voting power to 0 to remove). | 3 | 699 | consensus_param_updates | [ConsensusParams](#consensusparams) | Changes to gas, size, and other consensus-related parameters. | 4 | 700 | app_hash | bytes | The Merkle root hash of the application state. | 5 | 701 702 * **Usage**: 703 * Contains the fields of the newly decided block. 704 * This method is equivalent to the call sequence `BeginBlock`, [`DeliverTx`], 705 and `EndBlock` in the previous version of ABCI. 706 * The height and time values match the values from the header of the proposed block. 707 * The Application can use `RequestFinalizeBlock.decided_last_commit` and `RequestFinalizeBlock.misbehavior` 708 to determine rewards and punishments for the validators. 709 * The Application executes the transactions in `RequestFinalizeBlock.txs` deterministically, 710 according to the rules set up by the Application, before returning control to CometBFT. 711 Alternatively, it can apply the candidate state corresponding to the same block previously 712 executed via `PrepareProposal` or `ProcessProposal`. 713 * `ResponseFinalizeBlock.tx_results[i].Code == 0` only if the _i_-th transaction is fully valid. 714 * The Application must provide values for `ResponseFinalizeBlock.app_hash`, 715 `ResponseFinalizeBlock.tx_results`, `ResponseFinalizeBlock.validator_updates`, and 716 `ResponseFinalizeBlock.consensus_param_updates` as a result of executing the block. 717 * The values for `ResponseFinalizeBlock.validator_updates`, or 718 `ResponseFinalizeBlock.consensus_param_updates` may be empty. In this case, CometBFT will keep 719 the current values. 720 * `ResponseFinalizeBlock.validator_updates`, triggered by block `H`, affect validation 721 for blocks `H+1`, `H+2`, and `H+3`. Heights following a validator update are affected in the following way: 722 * Height `H+1`: `NextValidatorsHash` includes the new `validator_updates` value. 723 * Height `H+2`: The validator set change takes effect and `ValidatorsHash` is updated. 724 * Height `H+3`: `*_last_commit` fields in `PrepareProposal`, `ProcessProposal`, and 725 `FinalizeBlock` now include the altered validator set. 726 * `ResponseFinalizeBlock.consensus_param_updates` returned for block `H` apply to the consensus 727 params for block `H+1`. For more information on the consensus parameters, 728 see the [consensus parameters](./abci%2B%2B_app_requirements.md#consensus-parameters) 729 section. 730 * `ResponseFinalizeBlock.app_hash` contains an (optional) Merkle root hash of the application state. 731 * `ResponseFinalizeBlock.app_hash` is included as the `Header.AppHash` in the next block. 732 * `ResponseFinalizeBlock.app_hash` may also be empty or hard-coded, but MUST be 733 **deterministic** - it must not be a function of anything that did not come from the parameters 734 of `RequestFinalizeBlock` and the previous committed state. 735 * Later calls to `Query` can return proofs about the application state anchored 736 in this Merkle root hash. 737 * The implementation of `FinalizeBlock` MUST be deterministic, since it is 738 making the Application's state evolve in the context of state machine replication. 739 * Currently, CometBFT will fill up all fields in `RequestFinalizeBlock`, even if they were 740 already passed on to the Application via `RequestPrepareProposal` or `RequestProcessProposal`. 741 742 #### When does CometBFT call `FinalizeBlock`? 743 744 When a node _p_ is in consensus height _h_, and _p_ receives 745 746 * the Proposal message with block _v_ for a round _r_, along with all its block parts, from _q_, 747 which is the proposer of round _r_, height _h_, 748 * `Precommit` messages from _2f + 1_ validators' voting power for round _r_, height _h_, 749 precommitting the same block _id(v)_, 750 751 then _p_ decides block _v_ and finalizes consensus for height _h_ in the following way 752 753 1. _p_ persists _v_ as the decision for height _h_. 754 2. _p_'s CometBFT calls `RequestFinalizeBlock` with _v_'s data. The call is synchronous. 755 3. _p_'s Application executes block _v_. 756 4. _p_'s Application calculates and returns the _AppHash_, along with a list containing 757 the outputs of each of the transactions executed. 758 5. _p_'s CometBFT hashes all the transaction outputs and stores it in _ResultHash_. 759 6. _p_'s CometBFT persists the transaction outputs, _AppHash_, and _ResultsHash_. 760 7. _p_'s CometBFT locks the mempool — no calls to `CheckTx` on new transactions. 761 8. _p_'s CometBFT calls `RequestCommit` to instruct the Application to persist its state. 762 9. _p_'s CometBFT, optionally, re-checks all outstanding transactions in the mempool 763 against the newly persisted Application state. 764 10. _p_'s CometBFT unlocks the mempool — newly received transactions can now be checked. 765 11. _p_ starts consensus for height _h+1_, round 0 766 767 --> 768 769 ## Data Types existing in ABCI 770 771 Most of the data structures used in ABCI are shared [common data structures](../core/data_structures.md). In certain cases, ABCI uses different data structures which are documented here: 772 773 ### Validator 774 775 * **Fields**: 776 777 | Name | Type | Description | Field Number | 778 |---------|-------|---------------------------------------------------------------------|--------------| 779 | address | bytes | [Address](../core/data_structures.md#address) of validator | 1 | 780 | power | int64 | Voting power of the validator | 3 | 781 782 * **Usage**: 783 * Validator identified by address 784 * Used in RequestBeginBlock as part of VoteInfo 785 * Does not include PubKey to avoid sending potentially large quantum pubkeys 786 over the ABCI 787 788 ### ValidatorUpdate 789 790 * **Fields**: 791 792 | Name | Type | Description | Field Number | 793 |---------|--------------------------------------------------|-------------------------------|--------------| 794 | pub_key | [Public Key](../core/data_structures.md#pub_key) | Public key of the validator | 1 | 795 | power | int64 | Voting power of the validator | 2 | 796 797 * **Usage**: 798 * Validator identified by PubKey 799 * Used to tell CometBFT to update the validator set 800 801 ### Misbehavior 802 803 * **Fields**: 804 805 | Name | Type | Description | Field Number | 806 |--------------------|-------------------------------------------------|------------------------------------------------------------------------------|--------------| 807 | type | [MisbehaviorType](#misbehaviortype) | Type of the misbehavior. An enum of possible misbehaviors. | 1 | 808 | validator | [Validator](#validator) | The offending validator | 2 | 809 | height | int64 | Height when the offense occurred | 3 | 810 | time | [google.protobuf.Timestamp][protobuf-timestamp] | Timestamp of the block that was committed at height `height` | 4 | 811 | total_voting_power | int64 | Total voting power of the validator set at height `height` | 5 | 812 813 #### MisbehaviorType 814 815 * **Fields** 816 817 MisbehaviorType is an enum with the listed fields: 818 819 | Name | Field Number | 820 |---------------------|--------------| 821 | UNKNOWN | 0 | 822 | DUPLICATE_VOTE | 1 | 823 | LIGHT_CLIENT_ATTACK | 2 | 824 825 ### ConsensusParams 826 827 * **Fields**: 828 829 | Name | Type | Description | Field Number | 830 |-----------|---------------------------------------------------------------|------------------------------------------------------------------------------|--------------| 831 | block | [BlockParams](../core/data_structures.md#blockparams) | Parameters limiting the size of a block and time between consecutive blocks. | 1 | 832 | evidence | [EvidenceParams](../core/data_structures.md#evidenceparams) | Parameters limiting the validity of evidence of byzantine behaviour. | 2 | 833 | validator | [ValidatorParams](../core/data_structures.md#validatorparams) | Parameters limiting the types of public keys validators can use. | 3 | 834 | version | [VersionsParams](../core/data_structures.md#versionparams) | The ABCI application version. | 4 | 835 836 ### ProofOps 837 838 * **Fields**: 839 840 | Name | Type | Description | Field Number | 841 |------|------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------| 842 | ops | repeated [ProofOp](#proofop) | List of chained Merkle proofs, of possibly different types. The Merkle root of one op is the value being proven in the next op. The Merkle root of the final op should equal the ultimate root hash being verified against.. | 1 | 843 844 ### ProofOp 845 846 * **Fields**: 847 848 | Name | Type | Description | Field Number | 849 |------|--------|------------------------------------------------|--------------| 850 | type | string | Type of Merkle proof and how it's encoded. | 1 | 851 | key | bytes | Key in the Merkle tree that this proof is for. | 2 | 852 | data | bytes | Encoded Merkle proof for the key. | 3 | 853 854 ### Snapshot 855 856 * **Fields**: 857 858 | Name | Type | Description | Field Number | 859 |----------|--------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------| 860 | height | uint64 | The height at which the snapshot was taken (after commit). | 1 | 861 | format | uint32 | An application-specific snapshot format, allowing applications to version their snapshot data format and make backwards-incompatible changes. CometBFT does not interpret this. | 2 | 862 | chunks | uint32 | The number of chunks in the snapshot. Must be at least 1 (even if empty). | 3 | 863 | hash | bytes | An arbitrary snapshot hash. Must be equal only for identical snapshots across nodes. CometBFT does not interpret the hash, it only compares them. | 4 | 864 | metadata | bytes | Arbitrary application metadata, for example chunk hashes or other verification data. | 5 | 865 866 * **Usage**: 867 * Used for state sync snapshots, see the [state sync section](../p2p/legacy-docs/messages/state-sync.md) for details. 868 * A snapshot is considered identical across nodes only if _all_ fields are equal (including 869 `Metadata`). Chunks may be retrieved from all nodes that have the same snapshot. 870 * When sent across the network, a snapshot message can be at most 4 MB. 871 872 ## Data types introduced or modified in ABCI++ 873 874 ### VoteInfo 875 876 * **Fields**: 877 878 | Name | Type | Description | Field Number | 879 |-----------------------------|-------------------------|----------------------------------------------------------------|--------------| 880 | validator | [Validator](#validator) | The validator that sent the vote. | 1 | 881 | signed_last_block | bool | Indicates whether or not the validator signed the last block. | 2 | 882 883 * **Usage**: 884 * Indicates whether a validator signed the last block, allowing for rewards based on validator availability. 885 * This information is typically extracted from a proposed or decided block. 886 887 888 889 ### ExtendedVoteInfo 890 891 * **Fields**: 892 893 | Name | Type | Description | Field Number | 894 |-------------------|-------------------------|------------------------------------------------------------------------------|--------------| 895 | validator | [Validator](#validator) | The validator that sent the vote. | 1 | 896 | signed_last_block | bool | Indicates whether or not the validator signed the last block. | 2 | 897 | vote_extension | bytes | Reserved for future use. | 3 | 898 899 * **Usage**: 900 * Indicates whether a validator signed the last block, allowing for rewards based on validator availability. 901 * This information is extracted from CometBFT's data structures in the local process. 902 * `vote_extension` is reserved for future use when vote extensions are added. Currently, this field is always set to `nil`. 903 904 905 ### CommitInfo 906 907 * **Fields**: 908 909 | Name | Type | Description | Field Number | 910 |-------|--------------------------------|----------------------------------------------------------------------------------------------|--------------| 911 | round | int32 | Commit round. Reflects the round at which the block proposer decided in the previous height. | 1 | 912 | votes | repeated [VoteInfo](#voteinfo) | List of validators' addresses in the last validator set with their voting information. | 2 | 913 914 915 ### ExtendedCommitInfo 916 917 * **Fields**: 918 919 | Name | Type | Description | Field Number | 920 |-------|------------------------------------------------|-------------------------------------------------------------------------------------------------------------------|--------------| 921 | round | int32 | Commit round. Reflects the round at which the block proposer decided in the previous height. | 1 | 922 | votes | repeated [ExtendedVoteInfo](#extendedvoteinfo) | List of validators' addresses in the last validator set with their voting information, including vote extensions. | 2 | 923 924 <!-- 925 ### ExecTxResult 926 927 * **Fields**: 928 929 | Name | Type | Description | Field Number | 930 |------------|-------------------------------------------------------------|-----------------------------------------------------------------------|--------------| 931 | code | uint32 | Response code. | 1 | 932 | data | bytes | Result bytes, if any. | 2 | 933 | log | string | The output of the application's logger. **May be non-deterministic.** | 3 | 934 | info | string | Additional information. **May be non-deterministic.** | 4 | 935 | gas_wanted | int64 | Amount of gas requested for transaction. | 5 | 936 | gas_used | int64 | Amount of gas consumed by transaction. | 6 | 937 | events | repeated [Event](abci++_basic_concepts.md#events) | Type & Key-Value events for indexing transactions (e.g. by account). | 7 | 938 | codespace | string | Namespace for the `code`. | 8 | 939 940 --> 941 942 ### ProposalStatus 943 944 ```proto 945 enum ProposalStatus { 946 UNKNOWN = 0; // Unknown status. Returning this from the application is always an error. 947 ACCEPT = 1; // Status that signals that the application finds the proposal valid. 948 REJECT = 2; // Status that signals that the application finds the proposal invalid. 949 } 950 ``` 951 952 * **Usage**: 953 * Used within the [ProcessProposal](#processproposal) response. 954 * If `Status` is `UNKNOWN`, a problem happened in the Application. CometBFT will assume the application is faulty and crash. 955 * If `Status` is `ACCEPT`, the consensus algorithm accepts the proposal and will issue a Prevote message for it. 956 * If `Status` is `REJECT`, the consensus algorithm rejects the proposal and will issue a Prevote for `nil` instead. 957 958 <!-- 959 ### VerifyStatus 960 961 ```proto 962 enum VerifyStatus { 963 UNKNOWN = 0; // Unknown status. Returning this from the application is always an error. 964 ACCEPT = 1; // Status that signals that the application finds the vote extension valid. 965 REJECT = 2; // Status that signals that the application finds the vote extension invalid. 966 } 967 ``` 968 969 * **Usage**: 970 * Used within the [VerifyVoteExtension](#verifyvoteextension) response. 971 * If `Status` is `UNKNOWN`, a problem happened in the Application. CometBFT will assume the application is faulty and crash. 972 * If `Status` is `ACCEPT`, the consensus algorithm will accept the vote as valid. 973 * If `Status` is `REJECT`, the consensus algorithm will reject the vote as invalid. 974 975 976 ### CanonicalVoteExtension 977 978 >**TODO**: This protobuf message definition is not part of the ABCI++ interface, but rather belongs to the 979 > Precommit message which is broadcast via P2P. So it is to be moved to the relevant section of the spec. 980 981 * **Fields**: 982 983 | Name | Type | Description | Field Number | 984 |-----------|--------|--------------------------------------------------------------------------------------------|--------------| 985 | extension | bytes | Vote extension provided by the Application. | 1 | 986 | height | int64 | Height in which the extension was provided. | 2 | 987 | round | int32 | Round in which the extension was provided. | 3 | 988 | chain_id | string | ID of the blockchain running consensus. | 4 | 989 | address | bytes | [Address](../core/data_structures.md#address) of the validator that provided the extension | 5 | 990 991 * **Usage**: 992 * CometBFT is to sign the whole data structure and attach it to a Precommit message 993 * Upon reception, CometBFT validates the sender's signature and sanity-checks the values of `height`, `round`, and `chain_id`. 994 Then it sends `extension` to the Application via `RequestVerifyVoteExtension` for verification. 995 996 997 --> 998 999 [protobuf-timestamp]: https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#google.protobuf.Timestamp