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Reject trie nodes that exceed the branch-count limit - #141
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This was referenced Oct 17, 2026
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Limit nodes to 32767 branches so their counts cannot be mistaken for leaf markers after a segment. Reject an additional sibling before modifying trie data, while allowing existing branches to be updated or extended. Add regression coverage for rejected insertions preserving serialized data and mappings, and reuse a serialization helper in rejection tests.
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What Does This Do
Reject adding a 32,768th branch to a trie node before modifying its data. Existing branches can still be overwritten or extended at the limit.
Motivation
A branch count of 32,768 sets the leaf-marker bit. When that node follows a segment, lookup mistakes it for a leaf and existing mappings become unreadable.
Additional Notes
Use the literal
MAX_NODE_BRANCHES = 32767limit. The regression test verifies byte-for-byte preservation after rejection, existing mappings, and valid overwrites and extensions. Reuse a serialization helper in the rejection tests.Stack (merge in order):
This PR targets
mcculls/trie-empty-generation.Contributor Checklist