Sync BIP30/BIP34 Handling With Bitcoin Core#2467
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Upcoming commits tweak the conditions under which the expensive BIP30 duplicate-coinbase check should run. To unit-test those changes, this commit moves the decision logic out of BlockChain.checkConnectBlock and into a dedicated helper, bip0030CheckNeeded. The behaviour is unchanged; the new helper is covered by tests in bip30_test.go.
Sync the behaviour with Bitcoin Core. See bitcoin/bitcoin#6931 In Core, the BIP30 flag is cleared only if the previous block's ancestor chain already contains the BIP34 activation block. For the activation block itself (height = BIP0034Height), pindex->pprev->GetAncestor(BIP34Height) returns nullptr, so the flag stays on and BIP30 is still enforced. In other words, Core enforces BIP30 for the activation block and skips it starting with the following block.
Mirror BIP34-aware BIP30 skip logic from Bitcoin Core. PR bitcoin/bitcoin#6931 in Bitcoin Core introduced an optimization that skips the expensive BIP30 duplicate coinbase check once BIP34 is active *and* the chain actually contains the recorded activation block. See the comment in that PR "//Only continue to enforce if we're below BIP34 activation height or the block hash at that height doesn't correspond." btcd used to drop the check purely based on height. On a fork that lacks the BIP34 activation block, that difference lets a duplicate coinbase slip through consensus. This patch ports the missing pieces: we store the activation hash in chain parameters and only disable BIP30 after we see that block on-chain.
Bitcoin Core PR bitcoin/bitcoin#12204 tightened BIP30 handling: re-enable the check once height 1,983,702 is reached. This change ports that logic into btcd and adds a regression test.
Set regtest buried heights to match Core: BIP34/65/66 at height 1 and make CSV/SegWit/Taproot always active. Added regtest coverage for header version floors, coinbase height enforcement, and deployment state to ensure we now reject the blocks Core rejects and accept the ones Core accepts. Updated package fullblocktests to generate BIP34-compliant blocks. Test helpers now set prev block height to 0 (not the default -1) so generated blocks start at height 1 and satisfy coinbase height rules.
Pull Request Test Coverage Report for Build 20497333340Details
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Moved regtest sync to a separate PR #2469 since it reduces coverage and is unrelated to other commits. |
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cc: @bhandras for review |
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Diff looks good. I expect bip54 to be enabled soon, avoiding the return of the expensive bip30 verification. Nice work. |
starius
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PR btcsuite#2467 changed regtest to match Core's BIP34/65/66 activation rules, and the merged stack carries that (commit cd4e542 "regtest: align activations with Bitcoin Core"). Height-1 regtest blocks now need a BIP34-compliant coinbase height and a post-BIP66 block version. The failing tests came from commits added after PR btcsuite#2467 was opened on December 25, 2025 but before it merged on April 30, 2026: - c1a4612 ("blockchain: add ProcessBlockHeader") - f9645f0 ("blockchain: reuse existing header node in maybeAcceptBlock") - dc6e096 ("netsync: add TestSyncStateMachine for end-to-end IBD sync flow") - ce09426 ("netsync: add TestStartSyncBlockFallback for block-only sync path") - 2aae8a6 ("netsync: add TestStartSyncChainCurrent for chain-current noop path") Because those tests landed later, they kept the old regtest assumptions even though btcsuite#2467 had already been authored and tested against the older tree. Once btcsuite#2467 finally merged, these newer tests started building invalid regtest blocks and headers. Fix them by setting the genesis tip height to 0 before generating descendants, using Version 4 in the regtest block/header helpers, and encoding the test coinbase height with a minimal BIP34 push plus padding for the generic coinbase script-length rule.
allocz
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May 8, 2026
PR btcsuite#2467 changed regtest to match Core's BIP34/65/66 activation rules, and the merged stack carries that (commit cd4e542 "regtest: align activations with Bitcoin Core"). Height-1 regtest blocks now need a BIP34-compliant coinbase height and a post-BIP66 block version. The failing tests came from commits added after PR btcsuite#2467 was opened on December 25, 2025 but before it merged on April 30, 2026: - c1a4612 ("blockchain: add ProcessBlockHeader") - f9645f0 ("blockchain: reuse existing header node in maybeAcceptBlock") - dc6e096 ("netsync: add TestSyncStateMachine for end-to-end IBD sync flow") - ce09426 ("netsync: add TestStartSyncBlockFallback for block-only sync path") - 2aae8a6 ("netsync: add TestStartSyncChainCurrent for chain-current noop path") Because those tests landed later, they kept the old regtest assumptions even though btcsuite#2467 had already been authored and tested against the older tree. Once btcsuite#2467 finally merged, these newer tests started building invalid regtest blocks and headers. Fix them by setting the genesis tip height to 0 before generating descendants, using Version 4 in the regtest block/header helpers, and encoding the test coinbase height with a minimal BIP34 push plus padding for the generic coinbase script-length rule.
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Change Description
This PR aligns btcd's consensus logic with Bitcoin Core when deciding when to run the expensive BIP30 duplicate-coinbase check. The changes mirror the behavior introduced in bitcoin/bitcoin#6931 and bitcoin/bitcoin#12204.
Summary
bip0030CheckNeeded).1_983_702, matching Core’s protection against pre-BIP34 coinbases that serialized future heights.Steps to Test
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