feat(anvil): add --max-tx-inclusion-time-in-slot option

[spalladino]

To simulate real-world inclusion, it'd be handy to have Anvil include txs in the next block only if these txs were sent with enough time in advance to be picked up. I asked Claude to add this to Anvil as a flag, and here's the work it produced.

The PR is flagged as draft since I still want to make another pass myself at Claude's code, but before I do so, I'm curious if this feature would be in scope for Anvil, or it's not something you'd be interested in merging.

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Summary

• Adds a new --max-tx-inclusion-time-in-slot CLI option to anvil that simulates a validator transaction inclusion cutoff during interval mining
• When configured, transactions submitted after slot_start + max_tx_inclusion_time_in_slot are excluded from the current block and reconsidered in the next one
• Allows testing timing-sensitive logic (e.g. MEV, auction deadlines) more realistically against anvil

Semantics

• Option: --max-tx-inclusion-time-in-slot <SECONDS> (requires --block-time)
• Slot: [block_timestamp - block_time, block_timestamp)
• Inclusion rule: tx included if tx.submission_timestamp <= slot_start + max_tx_inclusion_time_in_slot
• Excluded txs remain in the pool and are reconsidered for the next block
• Default: None (disabled, preserving current behavior)

Changes

File	Change
crates/anvil/src/eth/pool/transactions.rs	Add timestamp: u64 to PoolTransaction
crates/anvil/src/eth/backend/time.rs	Add current_time() method to TimeManager
crates/anvil/src/eth/api.rs	Stamp transactions with current time at submission
crates/anvil/src/eth/backend/mem/mod.rs	Store config in Backend, filter in do_mine_block
crates/anvil/src/cmd.rs	Add --max-tx-inclusion-time-in-slot CLI arg
crates/anvil/src/config.rs	Add NodeConfig field and builder method
crates/anvil/tests/it/anvil.rs	4 new tests for inclusion, exclusion, carry-over, and default behavior

Test plan

• All 281 existing anvil tests pass
• 4 new tests covering:
  • Early tx included in block
  • Late tx excluded from block (remains in pool)
  • Excluded tx gets included in the next block
  • Default behavior (no option) includes all txs
• Manual test: anvil --block-time 12 --max-tx-inclusion-time-in-slot 4

🤖 Generated with Claude Code

[mattsse]

I feel like this is kinda similar to sendRawTransactionConditional

so I wonder if we should just adopt this as meta info on the pooled tx type instead?

then we could still layer the cli arg behaviour on top later and make this the default for all incoming txs?

does that make sense?

[spalladino]

Interesting! I didn't know ERC7796, but I think it makes sense. So, to double check I understood you correctly:

• We remove the timestamp field of the PoolTransaction in favor of a conditions struct, with a timestampMin or blockNumberMin (to be extended to all fields of sendRawTransactionConditional eventually)
• We check these fields when picking the txs to include on the next block
• We keep the max-tx-inclusion-time-in-slot CLI argument, and use it to manually populate the blockNumberMin based on the current time when the tx is received (ie we set blockNumberMin to currentBlock+2 if currentBlock.timestamp + maxInclusionTimeInSlot < currentTime)

Does it make sense?