First steps towards a stateless, side-effect free validation library #35906

pull purpleKarrot wants to merge 5 commits into bitcoin:master from purpleKarrot:validation changing 5 files +300 −15

purpleKarrot commented at 6:50 PM on August 5, 2026: contributor
This implements the following actions from #35904:
1. Expose the validation interface
  
  Make the existing CheckBlockHeader, ContextualCheckBlockHeader, and ContextualCheckBlock functions part of the public validation interface by declaring them in validation.h.
2. Interface Segregation: Remove dependency on ChainstateManager
  
  ContextualCheck* functions need a ChainstateManager only to access the consensus parameters. Pass Consensus::Params instead and access them at the call site.
3. Make environmental dependencies explicit
  
  Pass the validation time explicitly to ContextualCheckBlockHeader instead of reading the system clock internally.
DrahtBot commented at 6:50 PM on August 5, 2026: contributor


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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35906.



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Conflicts

Reviewers, this pull request conflicts with the following ones:
- #35820 (refactor: keep duration calculations typed by l0rinc)
- #35570 (refactor: Change some validation.cpp methods to return BlockValidationState by optout21)
- #30342 (kernel, logging: Pass Logger instances to kernel objects by ryanofsky)
If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

in src/validation.cpp:4123 in 7b358c2637 outdated

4119 | @@ -4121,14 +4120,14 @@ static bool ContextualCheckBlockHeader(const CBlockHeader& block, BlockValidatio
4120 |      }
4121 |  
4122 |      // Check timestamp
4123 | -    if (block.Time() > NodeClock::now() + std::chrono::seconds{MAX_FUTURE_BLOCK_TIME}) {
4124 | +    if (block.Time() > now + std::chrono::seconds{MAX_FUTURE_BLOCK_TIME}) {

maflcko commented at 6:54 AM on August 6, 2026:

This conflicts with #35557, which is an alternative to #35496.

No opinion on the merge order, but I think it would be good if the authors of all three alternatives provided reviews on each pull request, so that ideally the same line of code is only changed once.

in src/validation.cpp:4128 in 7b358c2637 outdated

4127 |  
4128 |      // Reject blocks with outdated version
4129 | -    if ((block.nVersion < 2 && DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_HEIGHTINCB)) ||
4130 | -        (block.nVersion < 3 && DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_DERSIG)) ||
4131 | -        (block.nVersion < 4 && DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_CLTV))) {
4132 | +    if ((block.nVersion < 2 && DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_HEIGHTINCB)) ||

maflcko commented at 6:57 AM on August 6, 2026:

this partially reverts 78adef17536edef833a0bfca06b61ce28120e486. Maybe that is fine, but if the motivation is better tests, maybe the refactor change would come with better tests included?

E.g. this pull conflicts with #34895, which seems to be adding tests.

purpleKarrot commented at 11:13 AM on August 7, 2026:

maybe the refactor change would come with better tests included

Good point. Done.

Make validation functions accessible

Make the existing `CheckBlockHeader`, `ContextualCheckBlockHeader`, and
`ContextualCheckBlock` functions part of the public validation interface
by declaring them in `validation.h`.

8bb61e96a7

Make `ContextualCheck*` not depend on `ChainstateManager`

`ContextualCheck*` functions need a `ChainstateManager` only to access
the consensus parameters. Pass `Consensus::Params` instead and access
them at the call site.

e2dd3a1696

Make `ContextualCheckHeader` not depend on system time

Pass the validation time explicitly to `ContextualCheckBlockHeader`
instead of reading the system clock internally.

28bf798910

validation: Add unit tests for `CheckBlockHeader` 95635188f2
purpleKarrot force-pushed on Aug 7, 2026
validation: Add unit tests for `ContextualCheckBlockHeader` ab1674de05

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#35904 Factoring out a stateless, side-effect free validation library

First steps towards a stateless, side-effect free validation library #35906

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