Introduce txpool.PendingFilter and migrate Pending(...) signatures from positional params to a typed struct.
- Add core/txpool.PendingFilter with MinTip/BaseFee fields for cheap call-site filtering
- Update txpool subpool interface and all call sites in eth/miner to pass the filter struct
- Keep behavior unchanged for empty filter (equivalent to previous nil,nil usage)
- Refresh legacypool tests to use the new API shape
This is a refactor-only change intended to improve API clarity and future extensibility without changing consensus or RPC semantics.
Introduce dynamic-fee pre-filtering in txpool pending retrieval to reduce
allocations and downstream processing work during mining and tx propagation.
What changed:
- Change the `Pending` API from `Pending(enforceTips bool)` to
`Pending(minTip *uint256.Int, baseFee *uint256.Int)` in txpool interfaces.
- Implement pre-filtering in `legacypool.Pending` by comparing effective tip
against the provided `minTip/baseFee` for non-local, non-special txs.
- Update call sites to the new API:
- miner work assembly (`miner/worker.go`)
- tx sync (`eth/sync.go`)
- pool transaction retrieval (`eth/api_backend.go`)
- protocol/test interfaces (`eth/protocol.go`, `eth/helper_test.go`).
Tests:
- Add targeted coverage for pending filtering semantics in
`core/txpool/legacypool/legacypool_test.go`, including:
- minTip threshold boundary behavior
- baseFee-aware effective tip filtering
- local/special transaction exemption behavior
- dynamic-fee boundary behavior when baseFee is nil.
Impact:
- Preserves existing behavior while making pending selection cheaper for
downstream consumers.
- Improves confidence in edge-case behavior through dedicated tests.
