refactor(forks/lstar): make the genesis anchor slot explicit#808
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tcoratger merged 1 commit intoMay 31, 2026
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Anchoring the genesis block as justified and finalized swapped in the parent root but kept the pre-state checkpoint slot. That was correct only because both checkpoint slots are still zero when the first post-genesis block is processed, a hidden dependency a reader had to reconstruct. Write the slot as zero directly at both the header-processing anchor and its mirror in the block builder, so the genesis anchor reads as a fixed slot-zero checkpoint. No behavior change. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Summary
When the first post-genesis block is processed, the genesis block is forced to be justified and finalized. The code swapped in the parent root but kept the pre-state checkpoint slot:
This is correct only because both checkpoint slots are still
0at that point (genesis initializes them toSlot(0), and slot processing never touches checkpoints). A reader had to reconstruct that invariant to convince themselves the slot was right.This writes the slot as
Slot(0)directly, at both the header-processing anchor and its mirror in the block builder, so the genesis anchor reads as a fixed slot-zero checkpoint with no hidden dependency on the pre-state.No behavior change —
state.latest_justified.slotandstate.latest_finalized.slotare provably0on both paths (each builds on the genesis state).Testing
just lint(ruff) — passedjust typecheck(ty) — passedtests/.../lstar/state/+test_block_production_justification_gap) — 17 passed🤖 Generated with Claude Code