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author | Wladimir J. van der Laan <laanwj@gmail.com> | 2017-11-29 12:16:38 +0100 |
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committer | Wladimir J. van der Laan <laanwj@gmail.com> | 2017-11-29 12:16:45 +0100 |
commit | 46d1ebfcf854bf122340a121d668bbfb9e025cf2 (patch) | |
tree | bc07c8beb6a51ab9411f6720b580ee3b2bca0c5e /src | |
parent | e97039605e0de3ba9e2c266b21821e26c2437811 (diff) | |
parent | 9d811dc18b28ed2dd00ba219754764a76c4f859b (diff) | |
download | bitcoin-46d1ebfcf854bf122340a121d668bbfb9e025cf2.tar.xz |
Merge #11737: Document partial validation in ConnectBlock()
9d811dc Document partial validation in ConnectBlock() (Suhas Daftuar)
Pull request description:
`ConnectBlock()` relies on validation that happens in `ContextualCheckBlock()` and
`ContextualCheckBlockHeader()`. This has implications for implementing consensus
changes and handling software upgrade to ensure that nodes upgrading their
software end up enforcing all the consensus rules.
Tree-SHA512: 36a252af2221b0e5d5d6f8d5f8b16f8b566ca0db2d56242130a5523302c8757599ac234594a6a946c1689b260d18a32c2c7f8c3831304e78b9832e2ce5ac435a
Diffstat (limited to 'src')
-rw-r--r-- | src/validation.cpp | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/src/validation.cpp b/src/validation.cpp index 9d45ef5f81..d598a6994c 100644 --- a/src/validation.cpp +++ b/src/validation.cpp @@ -1667,6 +1667,18 @@ static bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockInd int64_t nTimeStart = GetTimeMicros(); // Check it again in case a previous version let a bad block in + // NOTE: We don't currently (re-)invoke ContextualCheckBlock() or + // ContextualCheckBlockHeader() here. This means that if we add a new + // consensus rule that is enforced in one of those two functions, then we + // may have let in a block that violates the rule prior to updating the + // software, and we would NOT be enforcing the rule here. Fully solving + // upgrade from one software version to the next after a consensus rule + // change is potentially tricky and issue-specific (see RewindBlockIndex() + // for one general approach that was used for BIP 141 deployment). + // Also, currently the rule against blocks more than 2 hours in the future + // is enforced in ContextualCheckBlockHeader(); we wouldn't want to + // re-enforce that rule here (at least until we make it impossible for + // GetAdjustedTime() to go backward). if (!CheckBlock(block, state, chainparams.GetConsensus(), !fJustCheck, !fJustCheck)) return error("%s: Consensus::CheckBlock: %s", __func__, FormatStateMessage(state)); @@ -2952,7 +2964,13 @@ std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBloc /** Context-dependent validity checks. * By "context", we mean only the previous block headers, but not the UTXO - * set; UTXO-related validity checks are done in ConnectBlock(). */ + * set; UTXO-related validity checks are done in ConnectBlock(). + * NOTE: This function is not currently invoked by ConnectBlock(), so we + * should consider upgrade issues if we change which consensus rules are + * enforced in this function (eg by adding a new consensus rule). See comment + * in ConnectBlock(). + * Note that -reindex-chainstate skips the validation that happens here! + */ static bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, const CChainParams& params, const CBlockIndex* pindexPrev, int64_t nAdjustedTime) { assert(pindexPrev != nullptr); @@ -2992,6 +3010,12 @@ static bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationSta return true; } +/** NOTE: This function is not currently invoked by ConnectBlock(), so we + * should consider upgrade issues if we change which consensus rules are + * enforced in this function (eg by adding a new consensus rule). See comment + * in ConnectBlock(). + * Note that -reindex-chainstate skips the validation that happens here! + */ static bool ContextualCheckBlock(const CBlock& block, CValidationState& state, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev) { const int nHeight = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1; |