Forklift: rehearse a Portaldot transaction on a fork, then send the same bytes

#showdev #blockchain #devtools #python

Your transaction runs twice. The first time is a rehearsal.

Forklift pins a Portaldot block, lifts the chain's real state at that block, forks it on your machine and checks the fork against the live chain key by key. Then forklift rehearse signs a transaction once, applies those exact bytes on the fork as the prediction, and with --send sends the same bytes to the V3 testnet and lists every field that differs.

What is measured on the V3 testnet

Lift at #118,061: 5,508 keys. verify --sample 200 exits 0: 200/200 draws identical, key set 5,508 = 5,508.
Rehearse: three real V3 transactions, each predicted on a fork first, then sent: 118555-1 System.remark, 118621-1 Balances.transfer_keep_alive, 118669-1 Utility.batch. Each had the same tx hash, success and event sequence as predicted, and the same recipient delta where there is one.
What differed: the fee-bearing event amounts, the fee (3,660 to 8,269 planck), the signer delta and the inclusion height. Forklift lists every one and exits 7, never a quiet fix.
Replay re-runs a V3 extrinsic on a fork of its parent block: 118555-1 10/10, 118621-1 14/14, 118669-1 16/16 fields equal.
Fork Receipt v2, a Revive contract on V3 at 0x52f0edd92af9ff410ca63ccc83735552e1b2abc7 (84 bytes): the emitted event and the stored receipt() equal the #118,061 manifest.

Mainnet, too

Three mainnet extrinsics replayed field-equal on a fork of their parent block (24/24, 25/25, 24/24). runtime-diff and migrate-report compare mainnet spec 1002 with V3: of a 16,324-key lift, 10,499 keys carry over, 5,443 re-encode and 382 have no home on V3.

Things I learned

A fee difference is not a bug, but it must be said. Each transaction landed a few blocks after its prediction, so the fee moved. Listing it, with an exit code, is more useful than hiding it.
Sampling is honest only if you say it is a sample. verify checks 200 random keys, not every key, and Forklift says so.

Honest limits

A V3 fork is Chopsticks, not a V3 node (no public V3 node binary exists). Forklift reads mainnet and V3; the only writes to a real chain are rehearse --send and receipt --target v3, and only to V3. The PyPI package is not published yet.

DEV Community

Forklift: rehearse a Portaldot transaction on a fork, then send the same bytes

What is measured on the V3 testnet

Mainnet, too

Things I learned

Honest limits

Links

Top comments (0)