Root cause: seq.del(i) does swap-with-last (destroys sorted order)
while seq.delete(i) preserves order. This caused massive data loss
during B-tree removes.
Changes:
- btree.nim: Replace seq.del with seq.delete (critical data corruption fix)
- btree.nim: search() traverses leaf linked list for duplicate boundary keys
- btree.nim: splitChild() consolidates duplicate boundary key values before split
- btree.nim: len() counts unique keys via leaf traversal
- btree.nim: remove() traverses leaf linked list to remove ALL occurrences
- btree.nim: Fix separator update in internal node (node.keys[i-1] not [i])
- prop_test.nim: Use set equality for interleaved test (rebalancing reorders)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
- prop_test.nim: 11 new property-based B-Tree invariants
(size accuracy, get roundtrip, scan ordering, range correctness,
contains, remove, large order, duplicates, empty tree, interleaved ops)
- bench_all.nim: JSON-based benchmark result tracking with regression
comparison against previous runs; each benchmark reports ops/sec
delta vs last run
dimgigov