* fix(scanner,data-usage): fix add() logic inversion and usize underflow in reduce_children_of
Bug #1: add() had inverted logic — returned early when children were present,
making the recursive child traversal dead code. Leaf compaction path was
completely non-functional. Fixed by recursing into children when present and
collecting leaves only at leaf nodes.
Bug #2: reduce_children_of used which underflows in debug
(panic) or release (wraps to usize::MAX, compacts entire cache). Fixed with
saturating_sub.
Both bugs existed identically in crates/scanner and crates/data-usage.
Added 5 tests covering add() subtree traversal, edge cases, and
reduce_children_of compaction behavior.
Closesrustfs/backlog#652
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* fix: collect internal nodes as compaction candidates, not leaves
The previous fix for add() collected leaf nodes (children empty) as
compaction candidates. This is incorrect: total_children_rec returns 0
for leaves, so compacting them never decrements — the
compaction loop makes no progress.
Collect internal nodes (children non-empty) instead. Compacting an
internal node removes its subtree via delete_recursive, which actually
reduces the total child count. Leaf nodes are skipped since they have
no children to remove.
Updated tests to match the corrected semantics.
* refactor: rename leaves→candidates, add data-usage regression tests
- Rename misleading variable/parameter to in
add() and reduce_children_of() for both crates
- Add 4 regression tests in crates/data-usage covering add() candidate
selection and reduce_children_of() compaction + saturating_sub
* fix: address data usage compaction review feedback
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Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: houseme <housemecn@gmail.com>
