Change signature of GetSubtrees

go/store/prolly/tree/blob_builder_test.go

@@ -191,8 +191,7 @@ func TestWriteImmutableTree(t *testing.T) {
 				root, err = root.loadSubtrees()
 				require.NoError(t, err)
 				for i := range expSubtrees {
-					sc, err := root.getSubtreeCount(i)
-					require.NoError(t, err)
+					sc := root.GetSubtreeCount(i)
 					assert.Equal(t, expSubtrees[i], sc)
 				}
 			}

go/store/prolly/tree/chunker.go

@@ -295,10 +295,7 @@ func insertNode[K ~[]byte, S message.Serializer, O Ordering[K]](ctx context.Cont
 			return err
 		}
 		for i := 0; i < nd.Count(); i++ {
-			subtreeCount, err := nd.getSubtreeCount(i)
-			if err != nil {
-				return err
-			}
+			subtreeCount := nd.GetSubtreeCount(i)
 			err = insertNode[K, S, O](ctx, tc, nil, K(nd.GetKey(i)), nd.getAddress(i), subtreeCount, level-1, order)
 			if err != nil {
 				return err

go/store/prolly/tree/node.go

@@ -174,12 +174,12 @@ func (nd Node) loadSubtrees() (Node, error) {
 	return nd, err
 }
 
-func (nd Node) getSubtreeCount(i int) (uint64, error) {
+func (nd Node) GetSubtreeCount(i int) uint64 {
 	if nd.IsLeaf() {
-		return 1, nil
+		return 1
 	}
 	// this will panic unless subtrees were loaded.
-	return (*nd.subtrees)[i], nil
+	return (*nd.subtrees)[i]
 }
 
 // getAddress returns the |ith| address of this node.

go/store/prolly/tree/node_cursor.go

@@ -114,7 +114,7 @@ func newCursorAtOrdinal(ctx context.Context, ns NodeStore, nd Node, ord uint64)
 		nd, _ = nd.loadSubtrees()
 
 		for idx = 0; idx < nd.Count(); idx++ {
-			cnt, _ := nd.getSubtreeCount(idx)
+			cnt := nd.GetSubtreeCount(idx)
 			card := int64(cnt)
 			if (distance - card) < 0 {
 				break
@@ -150,10 +150,7 @@ func getOrdinalOfCursor(curr *cursor) (ord uint64, err error) {
 		}
 
 		for idx := curr.idx - 1; idx >= 0; idx-- {
-			cnt, err := curr.nd.getSubtreeCount(idx)
-			if err != nil {
-				return 0, err
-			}
+			cnt := curr.nd.GetSubtreeCount(idx)
 			ord += cnt
 		}
 	}
@@ -294,10 +291,7 @@ func recursiveFetchLeafNodeSpan(ctx context.Context, ns NodeStore, nodes []Node,
 		}
 
 		for i := 0; i < nd.Count(); i++ {
-			card, err := nd.getSubtreeCount(i)
-			if err != nil {
-				return nil, 0, err
-			}
+			card := nd.GetSubtreeCount(i)
 
 			if acc == 0 && card < start {
 				start -= card
@@ -392,7 +386,7 @@ func (cur *cursor) currentSubtreeSize() (uint64, error) {
 	if err != nil {
 		return 0, err
 	}
-	return cur.nd.getSubtreeCount(cur.idx)
+	return cur.nd.GetSubtreeCount(cur.idx), nil
 }
 
 func (cur *cursor) firstKey() Item {

go/store/prolly/tree/stats_test.go

@@ -84,8 +84,7 @@ func histLevelCount(t *testing.T, nodes []Node) int {
 			n, err := n.loadSubtrees()
 			require.NoError(t, err)
 			for i := 0; i < n.Count(); i++ {
-				subCnt, err := n.getSubtreeCount(i)
-				require.NoError(t, err)
+				subCnt := n.GetSubtreeCount(i)
 				cnt += int(subCnt)
 			}
 		}