Gballet asked on PR #34055 to unexport nodeRef, nodeKind, and makeRef
(comments 3099846639, 3099847640, 3100717855) — none are used outside
trie/bintrie. Cascade to the internal-only support symbols and methods:
NodeKind → nodeKind
KindEmpty/... → kindEmpty/...
NodeRef → nodeRef
EmptyRef → emptyRef
MakeRef → makeRef
NodeStore.Root → deleted; inlined to s.root field access (same pkg)
NodeStore.SetRoot → deleted; inlined to s.root = ref
NodeStore.ComputeHash/SerializeNode/DeserializeNode(WithHash)/
CollectNodes/ToDot/GetHeight → lowercased
All 9 method signatures took or returned nodeRef so their export would
have tripped revive:unexported-return after the type rename. Zero
external callers means no API break. The private deserializeNode helper
was renamed to decodeNode to free the name for the newly-private
deserializeNode public function.
Pure rename; no behaviour change.
Replace the BinaryNode interface (which uses Go interface pointers that
the GC must scan) with NodeRef uint32 indices into typed arena pools.
NodeRef packs a 2-bit kind tag and 30-bit pool index into a single
uint32, making it invisible to the garbage collector.
NodeStore manages chunked typed pools per node kind:
- InternalNode pool: ZERO Go pointers (children are NodeRef, hash is
[32]byte) → allocated in noscan spans, GC skips entirely
- HashedNode pool: ZERO Go pointers → noscan spans
- StemNode pool: ONE pointer per node (valueData []byte) → minimal GC
For a trie with 25K InternalNodes, this reduces GC-scanned pointer-words
from ~125K to ~10K (85% reduction). CPU profiling showed 44% of time
in GC; this refactor directly addresses that bottleneck.
Serialization format is unchanged — the on-disk representation is
fully compatible. All existing tests pass.
