debug_executionWitness

Note

Served only when debug is named in --http.api or --ws.api; see Enabling Namespaces.

Warning

Witness of an epoch-closing block

On a block that closes an epoch, the witness comes from a re-execution that runs the epoch-closing applyIncentives call with the node’s current rewards counter rather than the counts the block distributed, so the witness for such a block can differ from the block’s real execution. Other blocks are unaffected. Tracked in #1589.

Re-executes a block from its parent’s state, system calls included, and returns what a stateless client needs to run the block again: the trie nodes, contract code, account and slot keys, and headers the execution and the state-root computation read. debug_executionWitnessByBlockHash does the same for a block hash.

Parameters

block parameter: QUANTITY|TAG [Required] - Hexadecimal block number, or one of the string tags latest, earliest, safe, or finalized. See the default block parameter. A block the node does not have fails with error -32001 and a message such as block not found: 0x5.

Returns

Object - The execution witness:

state: Array - DATA elements: the RLP-encoded account-trie and storage-trie nodes the execution and the state-root computation read.
codes: Array - DATA elements: the bytecode of every contract the execution loaded or created.
keys: Array - DATA elements: the unhashed keys behind the trie paths, 20-byte addresses for accounts and 32-byte slots for storage.
headers: Array - DATA elements: RLP-encoded headers from the oldest block the execution read with BLOCKHASH up to the parent block. When the block never runs BLOCKHASH, this is the parent header alone.

Example

Request

curl http://localhost:8545 \
 -X POST \
 -H "Content-Type: application/json" \
 --data '{"jsonrpc":"2.0","method":"debug_executionWitness","params":["0x1"],"id":1}'

Result

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "state": [
      "0x..." // RLP-encoded trie nodes, abbreviated
    ],
    "codes": [
      "0x..." // contract bytecode, abbreviated
    ],
    "keys": [
      "0xb14d3c4f5fbfbcfb98af2d330000d49c95b93aa7",
      "0x0000000000000000000000000000000000000000"
      // and the other accounts and storage slots the block touched
    ],
    "headers": [
      "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" // header of block 0x0, the parent
    ]
  }
}