Browser changes.

internal/atspi/document.go

@@ -93,14 +93,48 @@ type DocumentNode struct {
 type DocumentSnapshot struct {
 	Context DocumentContext
 	Nodes   []DocumentNode
+	data    *documentData
 }
 
 // Document copies the top-level document, including embedded documents but
 // excluding browser chrome and other tabs. A stale/incomplete capture fails
 // atomically. It does not use flat review's viewport-limited text ranges.
 func (tree *AccessibleTree) Document(ctx context.Context, reference ObjectReference) (DocumentSnapshot, error) {
-	tree.mu.RLock()
-	defer tree.mu.RUnlock()
+	view, err := tree.DocumentView(ctx, reference)
+	if err != nil {
+		return DocumentSnapshot{}, err
+	}
+	view.Nodes = append([]DocumentNode(nil), view.Nodes...)
+	view.data = nil
+	return view, nil
+}
+
+// DocumentView validates the complete document atomically and shares its
+// immutable data. Like NavigationDocument, the returned Nodes are read-only.
+func (tree *AccessibleTree) DocumentView(ctx context.Context, reference ObjectReference) (DocumentSnapshot, error) {
+	tree.mu.Lock()
+	defer tree.mu.Unlock()
+	view, err := tree.navigation_document_locked(ctx, reference)
+	if err != nil {
+		return DocumentSnapshot{}, err
+	}
+	if err := tree.validate_document_range_locked(ctx, view, 0, len(view.Nodes)-1); err != nil {
+		return DocumentSnapshot{}, err
+	}
+	return view, nil
+}
+
+// NavigationDocument shares immutable document data until Replace or removal
+// changes the tree. Callers must not modify Nodes or their nested slices. Dirty
+// entries remain in the view: navigation validates the path it actually uses
+// with ValidateDocumentRange rather than recapturing unrelated page updates.
+func (tree *AccessibleTree) NavigationDocument(ctx context.Context, reference ObjectReference) (DocumentSnapshot, error) {
+	tree.mu.Lock()
+	defer tree.mu.Unlock()
+	return tree.navigation_document_locked(ctx, reference)
+}
+
+func (tree *AccessibleTree) navigation_document_locked(ctx context.Context, reference ObjectReference) (DocumentSnapshot, error) {
 	if err := ctx.Err(); err != nil {
 		return DocumentSnapshot{}, err
 	}
@@ -108,7 +142,14 @@ func (tree *AccessibleTree) Document(ctx context.Context, reference ObjectRefere
 	if err != nil {
 		return DocumentSnapshot{}, err
 	}
-	result := DocumentSnapshot{Context: owner}
+	if data := tree.documents[owner.TopLevel.ID()]; data != nil {
+		return DocumentSnapshot{Context: owner, Nodes: data.nodes, data: data}, nil
+	}
+	capacity := 128
+	if owner.TopLevel.ID() == tree.root {
+		capacity = len(tree.nodes)
+	}
+	result := DocumentSnapshot{Context: owner, Nodes: make([]DocumentNode, 0, capacity)}
 	type pendingNode struct {
 		id     ObjectID
 		hidden bool
@@ -121,19 +162,10 @@ func (tree *AccessibleTree) Document(ctx context.Context, reference ObjectRefere
 		last := len(pending) - 1
 		next := pending[last]
 		pending = pending[:last]
-		entry := tree.nodes[next.id]
-		if entry.snapshotInvalid {
-			return DocumentSnapshot{}, ErrStaleSnapshot
-		}
-		if entry.childrenInvalid {
+		entry, present := tree.nodes[next.id]
+		if !present {
 			return DocumentSnapshot{}, ErrIncompleteTree
 		}
-		if entry.textInvalid {
-			return DocumentSnapshot{}, ErrStaleText
-		}
-		if entry.geometryInvalid {
-			return DocumentSnapshot{}, ErrStaleGeometry
-		}
 		hidden := next.hidden || entry.geometry.VisibilityKnown && !entry.geometry.Visible
 		parentEditable := false
 		if entry.hasParent {
@@ -153,6 +185,11 @@ func (tree *AccessibleTree) Document(ctx context.Context, reference ObjectRefere
 			pending = append(pending, pendingNode{entry.children[i], hidden})
 		}
 	}
+	result.data = new_document_data(result.Nodes)
 	populate_document_rows(&result)
+	if tree.documents == nil {
+		tree.documents = make(map[ObjectID]*documentData)
+	}
+	tree.documents[owner.TopLevel.ID()] = result.data
 	return result, nil
 }

internal/atspi/document_line.go

@@ -27,7 +27,7 @@ type DocumentLine struct {
 }
 
 func (tree *AccessibleTree) DocumentLineAtOffset(ctx context.Context, reference ObjectReference, offset int) (DocumentLine, error) {
-	document, err := tree.Document(ctx, reference)
+	document, err := tree.DocumentView(ctx, reference)
 	if err != nil {
 		return DocumentLine{}, err
 	}

internal/atspi/document_rows.go

@@ -12,10 +12,7 @@ import (
 // Derive rows from the already captured document. This performs no native
 // queries and keeps large tables bounded to 32 cells and 4096 bytes per row.
 func populate_document_rows(document *DocumentSnapshot) {
-	nodes := make(map[ObjectID]int, len(document.Nodes))
-	for index, node := range document.Nodes {
-		nodes[node.Reference.ID()] = index
-	}
+	nodes := document.data.indices
 	type rowKey struct {
 		table ObjectID
 		row   int
@@ -55,10 +52,19 @@ func populate_document_rows(document *DocumentSnapshot) {
 		owners[index] = key
 	}
 	texts := make(map[rowKey]string, len(rows))
+	dependencies := make(map[rowKey][]ObjectReference, len(rows))
 	for key, indices := range rows {
 		sort.SliceStable(indices, func(a, b int) bool {
 			return document.Nodes[indices[a]].Snapshot.TableColumnIndex < document.Nodes[indices[b]].Snapshot.TableColumnIndex
 		})
+		// Validation follows the same bounded set used to derive row text.
+		// Include cells past the byte limit too: shorter updated labels could
+		// make those cells newly contribute to the next row summary.
+		references := make([]ObjectReference, len(indices))
+		for index, member := range indices {
+			references[index] = document.Nodes[member].Reference
+		}
+		dependencies[key] = references
 		var parts []string
 		length := 0
 		for _, index := range indices {
@@ -78,7 +84,11 @@ func populate_document_rows(document *DocumentSnapshot) {
 		}
 		texts[key] = strings.Join(parts, ", ")
 	}
+	if len(owners) > 0 {
+		document.data.rows = make(map[ObjectID][]ObjectReference, len(owners))
+	}
 	for index, key := range owners {
 		document.Nodes[index].Snapshot.TableRowText = texts[key]
+		document.data.rows[document.Nodes[index].Reference.ID()] = dependencies[key]
 	}
 }

internal/atspi/document_view.go

@@ -0,0 +1,165 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package atspi
+
+import "context"
+
+// Owned by AccessibleTree under its mutex. Published data is immutable and can
+// outlive a replacement; ValidateDocumentRange rejects retired views. Dirty
+// flags stay in treeEntry, so an unrelated invalidation need not rebuild this.
+type documentData struct {
+	nodes   []DocumentNode
+	indices map[ObjectID]int
+	ends    []int
+	rows    map[ObjectID][]ObjectReference
+}
+
+func new_document_data(nodes []DocumentNode) *documentData {
+	data := &documentData{nodes: nodes, indices: make(map[ObjectID]int, len(nodes)), ends: make([]int, len(nodes))}
+	for index, node := range nodes {
+		data.indices[node.Reference.ID()] = index
+		data.ends[index] = index
+	}
+	for index := len(nodes) - 1; index > 0; index-- {
+		parent := data.indices[nodes[index].Parent]
+		data.ends[parent] = max(data.ends[parent], data.ends[index])
+	}
+	return data
+}
+
+// SameContent identifies a shared immutable view, not merely matching object
+// paths. A replacement with surviving identities still has different content.
+func (document DocumentSnapshot) SameContent(other DocumentSnapshot) bool {
+	return document.data != nil && document.data == other.data
+}
+
+func (document DocumentSnapshot) Index(id ObjectID) (int, bool) {
+	if document.data != nil {
+		index, ok := document.data.indices[id]
+		return index, ok
+	}
+	for index, node := range document.Nodes {
+		if node.Reference.ID() == id {
+			return index, true
+		}
+	}
+	return 0, false
+}
+
+func (document DocumentSnapshot) Node(id ObjectID) (DocumentNode, bool) {
+	index, ok := document.Index(id)
+	if !ok {
+		return DocumentNode{}, false
+	}
+	return document.Nodes[index], true
+}
+
+func (document DocumentSnapshot) SubtreeEnd(index int) int {
+	if document.data != nil {
+		return document.data.ends[index]
+	}
+	end := index
+	for next := index + 1; next < len(document.Nodes); next++ {
+		parent, ok := document.Index(document.Nodes[next].Parent)
+		if !ok || parent < index {
+			break
+		}
+		end = next
+	}
+	return end
+}
+
+func document_entry_error(entry treeEntry) error {
+	switch {
+	case entry.snapshotInvalid:
+		return ErrStaleSnapshot
+	case entry.childrenInvalid:
+		return ErrIncompleteTree
+	case entry.textInvalid:
+		return ErrStaleText
+	case entry.geometryInvalid:
+		return ErrStaleGeometry
+	}
+	return nil
+}
+
+// ValidateDocumentRange checks traversed objects, including skipped/hidden
+// candidates, before committing a move. Ancestor metadata always matters;
+// ancestor child order matters when crossing objects. A character move within
+// one live leaf therefore survives insertions elsewhere in its parent.
+func (tree *AccessibleTree) ValidateDocumentRange(ctx context.Context, document DocumentSnapshot, from, to int) error {
+	tree.mu.RLock()
+	defer tree.mu.RUnlock()
+	return tree.validate_document_range_locked(ctx, document, from, to)
+}
+
+// ValidateDocumentOrder also checks ancestor child order when a structural
+// search or a document-boundary jump will leave its current object.
+func (tree *AccessibleTree) ValidateDocumentOrder(ctx context.Context, document DocumentSnapshot, index int) error {
+	tree.mu.RLock()
+	defer tree.mu.RUnlock()
+	return tree.validate_document_path_locked(ctx, document, index, index, true)
+}
+
+func (tree *AccessibleTree) validate_document_range_locked(ctx context.Context, document DocumentSnapshot, from, to int) error {
+	return tree.validate_document_path_locked(ctx, document, from, to, from != to)
+}
+
+func (tree *AccessibleTree) validate_document_path_locked(ctx context.Context, document DocumentSnapshot, from, to int, requireOrder bool) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	if document.data == nil || tree.documents[document.Context.TopLevel.ID()] != document.data {
+		return ErrStaleObject
+	}
+	if from < 0 || to < 0 || from >= len(document.Nodes) || to >= len(document.Nodes) {
+		return ErrStaleObject
+	}
+	for index := min(from, to); index <= max(from, to); index++ {
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+		node := document.Nodes[index]
+		entry, err := tree.resolveLocked(node.Reference)
+		if err != nil {
+			return err
+		}
+		if err := document_entry_error(entry); err != nil {
+			return err
+		}
+		if err := tree.validate_document_row_locked(document, node.Reference.ID()); err != nil {
+			return err
+		}
+		for entry.hasParent {
+			entry = tree.nodes[entry.parent]
+			if entry.snapshotInvalid {
+				return ErrStaleSnapshot
+			}
+			if entry.geometryInvalid {
+				return ErrStaleGeometry
+			}
+			if requireOrder && entry.childrenInvalid {
+				return ErrIncompleteTree
+			}
+			if err := tree.validate_document_row_locked(document, entry.snapshot.ID()); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (tree *AccessibleTree) validate_document_row_locked(document DocumentSnapshot, id ObjectID) error {
+	for _, reference := range document.data.rows[id] {
+		entry, err := tree.resolveLocked(reference)
+		if err != nil {
+			return err
+		}
+		if err := document_entry_error(entry); err != nil {
+			return err
+		}
+	}
+	return nil
+}

internal/atspi/document_view_test.go

@@ -0,0 +1,163 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package atspi
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"testing"
+)
+
+func TestNavigationDocumentConcurrentReplacementKeepsViewsImmutable(t *testing.T) {
+	tree, _ := NewAccessibleTree(testID("/root"), documentTestNodes())
+	ref, _ := tree.Reference(testID("/heading"))
+	var workers sync.WaitGroup
+	workers.Add(1)
+	go func() {
+		defer workers.Done()
+		for range 100 {
+			nodes := documentTestNodes()
+			for index := range nodes {
+				nodes[index].Snapshot.Name = "Replacement"
+			}
+			if err := tree.Replace(testID("/root"), nodes); err != nil {
+				t.Error(err)
+				return
+			}
+		}
+	}()
+	defer workers.Wait()
+	for range 100 {
+		view, err := tree.NavigationDocument(context.Background(), ref)
+		if err != nil {
+			t.Fatal(err)
+		}
+		replaced := view.Context.Ancestors[0].Name == "Replacement"
+		for _, node := range view.Nodes {
+			if (node.Snapshot.Name == "Replacement") != replaced {
+				t.Fatal("mixed replacement data in shared view")
+			}
+		}
+		if err := tree.ValidateDocumentRange(context.Background(), view, 0, len(view.Nodes)-1); err != nil && !errors.Is(err, ErrStaleObject) {
+			t.Fatal(err)
+		}
+	}
+}
+
+func TestNavigationDocumentSharesOnlyImmutableData(t *testing.T) {
+	tree, _ := NewAccessibleTree(testID("/root"), documentTestNodes())
+	ref, _ := tree.Reference(testID("/heading"))
+	first, err := tree.NavigationDocument(context.Background(), ref)
+	if err != nil {
+		t.Fatal(err)
+	}
+	second, err := tree.NavigationDocument(context.Background(), ref)
+	if err != nil || !first.SameContent(second) || &first.Nodes[0] != &second.Nodes[0] {
+		t.Fatal("unchanged document data was rebuilt", err)
+	}
+	copy, err := tree.Document(context.Background(), ref)
+	if err != nil {
+		t.Fatal(err)
+	}
+	copy.Nodes[0].Snapshot.Name = "Changed copy"
+	if first.Nodes[0].Snapshot.Name == "Changed copy" {
+		t.Fatal("owned snapshot modified shared navigation data")
+	}
+	for index, node := range first.Nodes {
+		if got, ok := first.Index(node.Reference.ID()); !ok || got != index {
+			t.Fatalf("index for %v = %d, %v", node.Reference.ID(), got, ok)
+		}
+		if end := first.SubtreeEnd(index); end < index || end >= len(first.Nodes) {
+			t.Fatalf("invalid subtree end %d", end)
+		}
+	}
+}
+
+func TestNavigationDocumentValidatesOnlyTraversedBranches(t *testing.T) {
+	for _, test := range []struct {
+		name       string
+		invalidate func(*AccessibleTree)
+		want       error
+	}{
+		{"text", func(tree *AccessibleTree) { tree.InvalidateText(testID("/link")) }, ErrStaleText},
+		{"semantics", func(tree *AccessibleTree) { tree.InvalidateSnapshot(testID("/link")) }, ErrStaleSnapshot},
+		{"geometry", func(tree *AccessibleTree) { tree.InvalidateGeometry(testID("/inner")) }, ErrStaleGeometry},
+		{"children", func(tree *AccessibleTree) { tree.MarkChildrenChanged(testID("/inner")) }, ErrIncompleteTree},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			tree, _ := NewAccessibleTree(testID("/root"), documentTestNodes())
+			ref, _ := tree.Reference(testID("/heading"))
+			view, err := tree.NavigationDocument(context.Background(), ref)
+			if err != nil {
+				t.Fatal(err)
+			}
+			test.invalidate(tree)
+			current, err := tree.NavigationDocument(context.Background(), ref)
+			if err != nil || !current.SameContent(view) {
+				t.Fatal("unrelated dirty branch rebuilt document", err)
+			}
+			heading, _ := view.Index(ref.ID())
+			if err := tree.ValidateDocumentRange(context.Background(), view, heading, heading); err != nil {
+				t.Fatal("unrelated update blocked current heading", err)
+			}
+			if err := tree.ValidateDocumentRange(context.Background(), view, heading, len(view.Nodes)-1); !errors.Is(err, test.want) {
+				t.Fatalf("traversed stale branch: %v, want %v", err, test.want)
+			}
+		})
+	}
+}
+
+func TestNavigationDocumentRejectsRetiredViewsAndCanceledMoves(t *testing.T) {
+	tree, _ := NewAccessibleTree(testID("/root"), documentTestNodes())
+	ref, _ := tree.Reference(testID("/heading"))
+	view, _ := tree.NavigationDocument(context.Background(), ref)
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	if err := tree.ValidateDocumentRange(ctx, view, 0, 0); !errors.Is(err, context.Canceled) {
+		t.Fatal(err)
+	}
+	if err := tree.Replace(testID("/root"), documentTestNodes()); err != nil {
+		t.Fatal(err)
+	}
+	if err := tree.ValidateDocumentRange(context.Background(), view, 0, 0); !errors.Is(err, ErrStaleObject) {
+		t.Fatal("replacement retained old view", err)
+	}
+	fresh, _ := tree.NavigationDocument(context.Background(), ref)
+	if fresh.SameContent(view) {
+		t.Fatal("replacement reused navigation data")
+	}
+	tree.Invalidate(testID("/link"))
+	if err := tree.ValidateDocumentRange(context.Background(), fresh, 0, 0); !errors.Is(err, ErrStaleObject) {
+		t.Fatal("removal retained old topology", err)
+	}
+}
+
+func TestNavigationDocumentValidatesDerivedRowDependencies(t *testing.T) {
+	node := func(path, role string, children ...ObjectID) TreeNode {
+		n := testNode(path, path, children...)
+		n.Snapshot.Role = role
+		return n
+	}
+	nodes := []TreeNode{node("/doc", "document web", testID("/table")), node("/table", "table", testID("/first"), testID("/second")), node("/first", "table cell", testID("/text")), node("/text", "static"), node("/second", "table cell")}
+	for _, index := range []int{2, 4} {
+		nodes[index].Snapshot.TablePositionKnown = true
+		nodes[index].Snapshot.TableColumnIndex = index/2 - 1
+	}
+	tree, err := NewAccessibleTree(testID("/doc"), nodes)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ref, _ := tree.Reference(testID("/text"))
+	view, err := tree.NavigationDocument(context.Background(), ref)
+	if err != nil {
+		t.Fatal(err)
+	}
+	index, _ := view.Index(ref.ID())
+	tree.InvalidateText(testID("/second"))
+	if err := tree.ValidateDocumentRange(context.Background(), view, index, index); !errors.Is(err, ErrStaleText) {
+		t.Fatal("cached full row ignored a changed sibling cell", err)
+	}
+}

internal/atspi/tree.go

@@ -88,6 +88,7 @@ type AccessibleTree struct {
 	root           ObjectID
 	nodes          map[ObjectID]treeEntry
 	nextGeneration uint64
+	documents      map[ObjectID]*documentData
 }
 
 func NewAccessibleTree(root ObjectID, nodes []TreeNode) (*AccessibleTree, error) {
@@ -126,6 +127,7 @@ func (tree *AccessibleTree) Replace(root ObjectID, nodes []TreeNode) error {
 	}
 	tree.root = root
 	tree.nodes = next
+	tree.documents = nil
 	return nil
 }
 
@@ -352,6 +354,7 @@ func (tree *AccessibleTree) Invalidate(id ObjectID) int {
 	if !ok {
 		return 0
 	}
+	tree.documents = nil
 	if entry.hasParent {
 		parent := tree.nodes[entry.parent]
 		for index, childID := range parent.children {
@@ -392,6 +395,7 @@ func (tree *AccessibleTree) InvalidateChildren(parentID ObjectID) int {
 	if !ok {
 		return 0
 	}
+	tree.documents = nil
 	pending := append([]ObjectID(nil), parent.children...)
 	parent.children = nil
 	parent.childrenInvalid = true

internal/review/document.go

@@ -79,10 +79,13 @@ type documentPlace struct {
 // capture/recapture lifecycle. Methods serialize cursor state and do no native
 // work, key handling, focus changes, or speech.
 type DocumentCursor struct {
-	mu     sync.Mutex
-	tree   *atspi.AccessibleTree
-	places []documentPlace
-	active atspi.ObjectReference
+	mu            sync.Mutex
+	tree          *atspi.AccessibleTree
+	places        []documentPlace
+	active        atspi.ObjectReference
+	caretDocument atspi.DocumentSnapshot
+	caretRanges   []caretRange
+	lineOwners    map[int]atspi.ObjectID
 }
 
 // rebindPlace keeps the selected target after a semantic refresh retires its
@@ -155,7 +158,7 @@ func (cursor *DocumentCursor) ActivationTarget() (atspi.ObjectReference, error)
 		current = parent
 	}
 	if place.origin == StructuralNavigation && selectedHeading {
-		doc, err := cursor.tree.Document(context.Background(), place.object)
+		doc, err := cursor.tree.DocumentView(context.Background(), place.object)
 		if err != nil {
 			return atspi.ObjectReference{}, err
 		}
@@ -190,12 +193,13 @@ func (cursor *DocumentCursor) sync_focus(ctx context.Context, focus atspi.Object
 	if err != nil {
 		return DocumentPosition{}, "focus-unresolved", err
 	}
-	doc, err := cursor.tree.Document(ctx, ref)
+	doc, err := cursor.tree.NavigationDocument(ctx, ref)
 	if err != nil {
 		return DocumentPosition{}, "document-unresolved", err
 	}
 	place := documentPlace{document: doc.Context.TopLevel, object: ref, focus: ref}
 	recovery := "new-document"
+	removeIndex := -1
 	for index, saved := range cursor.places {
 		if saved.document != place.document {
 			if saved.document.ID() == place.document.ID() {
@@ -220,9 +224,19 @@ func (cursor *DocumentCursor) sync_focus(ctx context.Context, focus atspi.Object
 				place.object = parent.Reference
 			}
 		}
-		cursor.places = append(cursor.places[:index], cursor.places[index+1:]...)
+		removeIndex = index
 		break
 	}
+	placeIndex, ok := doc.Index(place.object.ID())
+	if !ok {
+		return DocumentPosition{}, "saved-object-missing", atspi.ErrStaleObject
+	}
+	if err := cursor.tree.ValidateDocumentRange(ctx, doc, placeIndex, placeIndex); err != nil {
+		return DocumentPosition{}, "document-unresolved", err
+	}
+	if removeIndex >= 0 {
+		cursor.places = append(cursor.places[:removeIndex], cursor.places[removeIndex+1:]...)
+	}
 	remember_text_parent(doc, &place)
 	if len(cursor.places) == 16 {
 		cursor.places = cursor.places[1:]
@@ -242,7 +256,7 @@ func (cursor *DocumentCursor) JumpToFragment(ctx context.Context, fragment strin
 		return DocumentPosition{}, false, ErrNoCurrent
 	}
 	place := &cursor.places[len(cursor.places)-1]
-	doc, err := cursor.tree.Document(ctx, place.object)
+	doc, err := cursor.tree.DocumentView(ctx, place.object)
 	if err != nil {
 		return DocumentPosition{}, false, err
 	}
@@ -334,7 +348,7 @@ func (cursor *DocumentCursor) Move(ctx context.Context, target DocumentTarget, l
 		return DocumentMoveResult{}, ErrNoCurrent
 	}
 	place := &cursor.places[len(cursor.places)-1]
-	doc, err := cursor.tree.Document(ctx, place.object)
+	doc, err := cursor.tree.NavigationDocument(ctx, place.object)
 	if err != nil {
 		return DocumentMoveResult{}, err
 	}
@@ -343,86 +357,64 @@ func (cursor *DocumentCursor) Move(ctx context.Context, target DocumentTarget, l
 	if doc.Context.TopLevel != place.document {
 		return DocumentMoveResult{}, atspi.ErrStaleObject
 	}
-	index := -1
-	for i, node := range doc.Nodes {
-		if node.Reference == place.object {
-			index = i
-			break
-		}
-	}
-	if index < 0 {
+	index, found := doc.Index(place.object.ID())
+	if !found || doc.Nodes[index].Reference != place.object {
 		return DocumentMoveResult{}, atspi.ErrStaleObject
 	}
-	// Python treats a focused descendant as being within its nearest matching
-	// ancestor. Anchor the search there so previous navigation does not select
-	// and reannounce the containing link, heading, or other target.
-	indexByID := make(map[atspi.ObjectID]int, len(doc.Nodes))
-	parentByID := make(map[atspi.ObjectID]atspi.ObjectID, len(doc.Nodes))
-	for candidateIndex, node := range doc.Nodes {
-		indexByID[node.Reference.ID()] = candidateIndex
-		for _, child := range node.Children {
-			parentByID[child] = node.Reference.ID()
-		}
+	if err := cursor.tree.ValidateDocumentOrder(ctx, doc, index); err != nil {
+		return DocumentMoveResult{}, err
 	}
-	for parent := place.object.ID(); parent.Valid(); parent = parentByID[parent] {
-		candidateIndex, ok := indexByID[parent]
+	// Anchor at the nearest matching ancestor without rebuilding parent maps.
+	for parent := place.object.ID(); parent.Valid(); {
+		candidate, ok := doc.Node(parent)
 		if !ok {
 			break
 		}
-		if documentTargetMatches(target, doc.Nodes[candidateIndex], level) {
-			index = candidateIndex
+		if documentTargetMatches(target, candidate, level) {
+			index, _ = doc.Index(parent)
 			break
 		}
+		parent = candidate.Parent
+	}
+	commit := func(targetIndex int, wrapped bool) (DocumentMoveResult, error) {
+		if err := cursor.tree.ValidateDocumentRange(ctx, doc, targetIndex, doc.SubtreeEnd(targetIndex)); err != nil {
+			return DocumentMoveResult{}, err
+		}
+		place.tableCell = atspi.ObjectID{}
+		place.object, place.origin, place.offset = doc.Nodes[targetIndex].Reference, StructuralNavigation, 0
+		remember_text_parent(doc, place)
+		return DocumentMoveResult{Position: documentPosition(doc, *place), Moved: true, Wrapped: wrapped}, nil
 	}
 	step := 1
 	if backwards {
 		step = -1
 	}
+	// Validate every traversed node, including nonmatches and hidden nodes: a
+	// dirty candidate must be refreshed before it can be skipped safely.
 	for i := index + step; i >= 0 && i < len(doc.Nodes); i += step {
-		node := doc.Nodes[i]
-		if node.Hidden {
-			continue
+		if err := cursor.tree.ValidateDocumentRange(ctx, doc, i-step, i); err != nil {
+			return DocumentMoveResult{}, err
 		}
-		match := documentTargetMatches(target, node, level)
-		if match {
-			place.tableCell = atspi.ObjectID{}
-			place.object = node.Reference
-			place.origin = StructuralNavigation
-			place.offset = 0
-			remember_text_parent(doc, place)
-			return DocumentMoveResult{Position: documentPosition(doc, *place), Moved: true}, nil
+		node := doc.Nodes[i]
+		if !node.Hidden && documentTargetMatches(target, node, level) {
+			return commit(i, false)
 		}
 	}
-	firstMatch, lastMatch := -1, -1
-	for i := 0; i < len(doc.Nodes); i++ {
-		node := doc.Nodes[i]
-		if node.Hidden {
-			continue
-		}
-		if !documentTargetMatches(target, node, level) {
-			continue
-		}
-		if firstMatch < 0 {
-			firstMatch = i
-		}
-		lastMatch = i
-	}
-	wrappedIndex := firstMatch
+	start, end := 0, index
 	if backwards {
-		wrappedIndex = lastMatch
+		start, end = len(doc.Nodes)-1, index
 	}
-	if wrappedIndex >= 0 {
-		node := doc.Nodes[wrappedIndex]
-		place.tableCell = atspi.ObjectID{}
-		place.object = node.Reference
-		place.origin = StructuralNavigation
-		place.offset = 0
-		remember_text_parent(doc, place)
-		return DocumentMoveResult{
-			Position: documentPosition(doc, *place),
-			Moved:    true,
-			Wrapped:  true,
-		}, nil
+	for i := start; ; i += step {
+		if err := cursor.tree.ValidateDocumentRange(ctx, doc, i, i); err != nil {
+			return DocumentMoveResult{}, err
+		}
+		node := doc.Nodes[i]
+		if !node.Hidden && documentTargetMatches(target, node, level) {
+			return commit(i, true)
+		}
+		if i == end {
+			break
+		}
 	}
 	return DocumentMoveResult{Position: documentPosition(doc, *place)}, nil
 }
@@ -536,12 +528,11 @@ func documentChunkRole(snapshot atspi.Snapshot) bool {
 }
 
 func documentObject(doc atspi.DocumentSnapshot, ref atspi.ObjectReference) (atspi.Snapshot, bool) {
-	for _, node := range doc.Nodes {
-		if node.Reference == ref {
-			return node.Snapshot, true
-		}
+	node, ok := doc.Node(ref.ID())
+	if !ok || node.Reference != ref {
+		return atspi.Snapshot{}, false
 	}
-	return atspi.Snapshot{}, false
+	return node.Snapshot, true
 }
 
 func documentPosition(doc atspi.DocumentSnapshot, place documentPlace) DocumentPosition {
@@ -560,26 +551,19 @@ func documentPosition(doc atspi.DocumentSnapshot, place documentPlace) DocumentP
 // readable caret position, matching Python's heading navigation. A heading
 // starting with plain text has no unambiguous link target.
 func linkedHeadingNode(doc atspi.DocumentSnapshot, heading atspi.ObjectReference) (atspi.DocumentNode, bool, bool) {
-	byID := make(map[atspi.ObjectID]atspi.DocumentNode, len(doc.Nodes))
-	parents := make(map[atspi.ObjectID]atspi.ObjectID, len(doc.Nodes))
-	for _, node := range doc.Nodes {
-		byID[node.Reference.ID()] = node
-		for _, child := range node.Children {
-			parents[child] = node.Reference.ID()
-		}
-	}
-	root, ok := byID[heading.ID()]
-	if !ok || root.Snapshot.Role != "heading" {
+	root, ok := doc.Node(heading.ID())
+	if !ok || root.Reference != heading || root.Snapshot.Role != "heading" {
 		return atspi.DocumentNode{}, false, false
 	}
-	for parent := parents[heading.ID()]; parent.Valid(); parent = parents[parent] {
-		node, found := byID[parent]
+	for parent := root.Parent; parent.Valid(); {
+		node, found := doc.Node(parent)
 		if !found || atspi.IsWebDocumentRole(node.Snapshot.Role) {
 			break
 		}
 		if node.Snapshot.Role == "link" {
 			return node, true, false
 		}
+		parent = node.Parent
 	}
 	var match atspi.DocumentNode
 	count := 0
@@ -587,7 +571,7 @@ func linkedHeadingNode(doc atspi.DocumentSnapshot, heading atspi.ObjectReference
 	for len(pending) != 0 && count < 2 {
 		id := pending[len(pending)-1]
 		pending = pending[:len(pending)-1]
-		node, found := byID[id]
+		node, found := doc.Node(id)
 		if !found || node.Hidden || node.Snapshot.Role == "heading" {
 			continue
 		}
@@ -607,7 +591,7 @@ func linkedHeadingNode(doc atspi.DocumentSnapshot, heading atspi.ObjectReference
 		for len(pending) != 0 {
 			id := pending[len(pending)-1]
 			pending = pending[:len(pending)-1]
-			node, found := byID[id]
+			node, found := doc.Node(id)
 			if !found || node.Hidden {
 				continue
 			}
@@ -622,7 +606,7 @@ func linkedHeadingNode(doc atspi.DocumentSnapshot, heading atspi.ObjectReference
 				continue
 			}
 			var firstLink atspi.DocumentNode
-			for ; id.Valid(); id = parents[id] {
+			for id.Valid() {
 				if id == heading.ID() {
 					if firstLink.Reference.Valid() {
 						// Gecko may omit plain text between child accessibles.
@@ -636,13 +620,17 @@ func linkedHeadingNode(doc atspi.DocumentSnapshot, heading atspi.ObjectReference
 					}
 					break
 				}
-				node := byID[id]
+				node, found := doc.Node(id)
+				if !found {
+					break
+				}
 				if node.Snapshot.Role == "heading" || atspi.IsWebDocumentRole(node.Snapshot.Role) {
 					break
 				}
 				if node.Snapshot.Role == "link" && !firstLink.Reference.Valid() {
 					firstLink = node
 				}
+				id = node.Parent
 			}
 			// Only the heading's starting caret position can select a link.
 			break

internal/review/document_benchmark_test.go

@@ -8,11 +8,87 @@ import (
 	"context"
 	"fmt"
 	"testing"
+	"time"
 	"unicode/utf8"
 
 	"git.stormux.org/storm/cthulhu/internal/atspi"
 )
 
+// Include focus synchronization and worker bookkeeping, which the primitive
+// heading benchmark intentionally excludes. Native provider work is separate.
+func BenchmarkDocumentWorkerHeadingNavigation(b *testing.B) {
+	for _, contentNodes := range []int{100, 1000, 10000} {
+		b.Run(fmt.Sprintf("nodes-%d", contentNodes), func(b *testing.B) {
+			tree, ids := benchmark_document_tree(b, contentNodes)
+			cursor, err := NewDocumentCursor(tree)
+			if err != nil {
+				b.Fatal(err)
+			}
+			worker, err := NewWorker(&fakeCapturer{}, time.Second)
+			if err != nil {
+				b.Fatal(err)
+			}
+			middle := contentNodes / 40 * 20
+			worker.SyncFocus(ids[middle])
+			ctx := context.Background()
+			if _, err := cursor.SyncFocus(ctx, ids[middle]); err != nil {
+				b.Fatal(err)
+			}
+			b.ReportAllocs()
+			for b.Loop() {
+				for _, backwards := range []bool{false, true} {
+					result, next := worker.moveDocument(ctx, cursor, DocumentHeading, 2, backwards, 0)
+					cursor = next
+					want := ids[middle+20]
+					if backwards {
+						want = ids[middle]
+					}
+					if result.Err != nil || !result.Moved || result.DocumentPosition.Object.ID() != want || result.DocumentDiagnostics.CaptureAttempts != 0 {
+						b.Fatalf("worker move: moved=%v error=%v", result.Moved, result.Err)
+					}
+				}
+			}
+		})
+	}
+}
+
+func BenchmarkDocumentCaretNavigation(b *testing.B) {
+	for _, contentNodes := range []int{100, 1000, 10000} {
+		b.Run(fmt.Sprintf("nodes-%d", contentNodes), func(b *testing.B) {
+			tree, ids := benchmark_document_tree(b, contentNodes)
+			cursor, err := NewDocumentCursor(tree)
+			if err != nil {
+				b.Fatal(err)
+			}
+			middle := contentNodes/2 + 2
+			ctx := context.Background()
+			if _, err := cursor.SyncFocus(ctx, ids[middle]); err != nil {
+				b.Fatal(err)
+			}
+			reader := caretTextReader{ids[middle]: fmt.Sprintf("Café sample %d", middle)}
+			// Build the view's reusable ranges before measuring repeated keys.
+			for _, command := range []DocumentCaretCommand{CaretNextCharacter, CaretPreviousCharacter} {
+				if _, err := cursor.MoveCaret(ctx, reader, command); err != nil {
+					b.Fatal(err)
+				}
+			}
+			b.ReportAllocs()
+			for b.Loop() {
+				for _, command := range []DocumentCaretCommand{CaretNextCharacter, CaretPreviousCharacter} {
+					move, err := cursor.MoveCaret(ctx, reader, command)
+					want := 1
+					if command == CaretPreviousCharacter {
+						want = 0
+					}
+					if err != nil || !move.Moved || move.Position.Object.ID() != ids[middle] || move.Position.Offset != want {
+						b.Fatalf("caret move: moved=%v error=%v", move.Moved, err)
+					}
+				}
+			}
+		})
+	}
+}
+
 // benchmark_document_tree models an already captured page, not native AT-SPI
 // capture. Each section has twenty content objects: a heading, a link, and
 // ordinary text. Pairs of objects share a visual row, including Unicode text.

internal/review/document_braille_routing.go

@@ -72,7 +72,7 @@ func (worker *Worker) route_document_braille(ctx context.Context, cursor *Docume
 		result.Err = atspi.ErrNoDocumentCaret
 		return
 	}
-	doc, err := cursor.tree.Document(ctx, target)
+	doc, err := cursor.tree.DocumentView(ctx, target)
 	if err != nil {
 		result.Err = err
 		return

internal/review/document_caret.go

@@ -83,37 +83,85 @@ func (cursor *DocumentCursor) MoveCaret(ctx context.Context, reader DocumentCare
 	if !cursor.active.Valid() || len(cursor.places) == 0 {
 		return DocumentCaretMove{}, ErrNoCurrent
 	}
-	place := &cursor.places[len(cursor.places)-1]
-	doc, err := cursor.tree.Document(ctx, place.object)
+	saved := &cursor.places[len(cursor.places)-1]
+	next := *saved
+	place := &next
+	doc, err := cursor.tree.NavigationDocument(ctx, place.object)
 	if err != nil {
 		return DocumentCaretMove{}, err
 	}
 	if doc.Context.TopLevel != place.document {
 		return DocumentCaretMove{}, atspi.ErrStaleObject
 	}
-	if command >= TableLeft {
-		return cursor.moveTable(ctx, doc, place, command)
-	}
-	place.tableCell = atspi.ObjectID{}
-	_, current := caret_node_indices(doc.Nodes, place.object)
-	indices := caretNodeRanges(doc.Nodes)
-	if current < 0 {
+	current, found := doc.Index(place.object.ID())
+	if !found || doc.Nodes[current].Reference != place.object {
 		return DocumentCaretMove{}, atspi.ErrStaleObject
 	}
+	if err := cursor.tree.ValidateDocumentRange(ctx, doc, current, current); err != nil {
+		return DocumentCaretMove{}, err
+	}
+	if command >= TableLeft {
+		// Table coordinates and row/header presentation consume the complete
+		// table, unlike ordinary caret movement's local text path.
+		if err := cursor.tree.ValidateDocumentRange(ctx, doc, 0, len(doc.Nodes)-1); err != nil {
+			return DocumentCaretMove{}, err
+		}
+		movement, err := cursor.moveTable(ctx, doc, place, command)
+		if err == nil && movement.Moved {
+			*saved = next
+		}
+		return movement, err
+	}
+	place.tableCell = atspi.ObjectID{}
+	if !doc.SameContent(cursor.caretDocument) {
+		cursor.caretDocument = doc
+		cursor.caretRanges = caretNodeRanges(doc.Nodes)
+		cursor.lineOwners = visual_line_owners(doc.Nodes)
+	}
+	indices := cursor.caretRanges
 	if len(indices) == 0 {
+		if err := cursor.tree.ValidateDocumentRange(ctx, doc, 0, len(doc.Nodes)-1); err != nil {
+			return DocumentCaretMove{}, err
+		}
 		return DocumentCaretMove{Position: documentPosition(doc, *place)}, nil
 	}
 	var movement DocumentCaretMove
+	navigationReader := &navigationTextReader{DocumentCaretReader: reader, tree: cursor.tree, document: doc, anchor: current}
+	reader = navigationReader
 	switch command {
 	case CaretNextWord, CaretPreviousWord, CaretNextCharacter, CaretPreviousCharacter:
 		movement, err = moveCaretText(ctx, reader, doc, place, indices, current,
 			command == CaretPreviousWord || command == CaretPreviousCharacter,
 			command == CaretNextWord || command == CaretPreviousWord)
 	default:
-		movement, err = move_caret_line(ctx, reader, cursor.tree, doc, place, indices, current, command)
+		movement, err = move_caret_line(ctx, reader, cursor.tree, doc, place, indices, current, command, cursor.lineOwners)
 	}
 	if err == nil && movement.Moved {
+		target, found := doc.Index(place.object.ID())
+		if !found {
+			return DocumentCaretMove{}, atspi.ErrStaleObject
+		}
+		// Successful text already belongs to this move even if the provider
+		// removes its ancestor immediately afterwards. Repeating that move
+		// during recovery would skip the line. Synthetic whole-object stops
+		// still need validation because they bypass the native text reader.
+		if !navigationReader.did_read(place.object) {
+			if err := cursor.tree.ValidateDocumentRange(ctx, doc, current, target); err != nil {
+				return DocumentCaretMove{}, err
+			}
+		}
 		remember_text_parent(doc, place)
+		*saved = next
+	} else if err == nil {
+		// Reaching a boundary must not silently skip newly readable text in a
+		// dirty object which had no caret range in the captured view.
+		boundary := len(doc.Nodes) - 1
+		if command == CaretPreviousCharacter || command == CaretPreviousWord || command == CaretPreviousLine || command == CaretDocumentStart {
+			boundary = 0
+		}
+		if err := cursor.tree.ValidateDocumentRange(ctx, doc, current, boundary); err != nil {
+			return DocumentCaretMove{}, err
+		}
 	}
 	return movement, err
 }

internal/review/document_lists.go

@@ -115,7 +115,7 @@ func (worker *Worker) listDocument(ctx context.Context, cursor *DocumentCursor,
 	if err != nil {
 		return list, err
 	}
-	doc, err := tree.Document(captureContext, ref)
+	doc, err := tree.DocumentView(captureContext, ref)
 	if err != nil {
 		return list, err
 	}
@@ -206,7 +206,7 @@ func (worker *Worker) selectDocumentList(ctx context.Context, cursor *DocumentCu
 		result.Err = err
 		return result, cursor
 	}
-	doc, err := list.tree.Document(ctx, position.Object)
+	doc, err := list.tree.DocumentView(ctx, position.Object)
 	if err != nil {
 		result.Err = err
 		return result, cursor

internal/review/document_native_caret.go

@@ -24,7 +24,7 @@ func (cursor *DocumentCursor) syncNativeCaret(ctx context.Context, reader Docume
 	cursor.mu.Lock()
 	defer cursor.mu.Unlock()
 	place := &cursor.places[len(cursor.places)-1]
-	doc, err := cursor.tree.Document(ctx, place.focus)
+	doc, err := cursor.tree.DocumentView(ctx, place.focus)
 	if err != nil {
 		return err
 	}
@@ -40,11 +40,7 @@ func (cursor *DocumentCursor) syncNativeCaret(ctx context.Context, reader Docume
 }
 
 func native_caret_node(ctx context.Context, reader DocumentCaretReader, doc atspi.DocumentSnapshot, focus atspi.ObjectID, offset int) (atspi.DocumentNode, int, error) {
-	nodes := make(map[atspi.ObjectID]atspi.DocumentNode, len(doc.Nodes))
-	for _, node := range doc.Nodes {
-		nodes[node.Reference.ID()] = node
-	}
-	node := nodes[focus]
+	node, _ := doc.Node(focus)
 	if !node.Reference.Valid() || offset < 0 || offset > node.Snapshot.CharacterCount || node.Snapshot.Editable || node.Snapshot.Role == "password text" {
 		return atspi.DocumentNode{}, 0, atspi.ErrNoDocumentCaret
 	}
@@ -60,7 +56,7 @@ func native_caret_node(ctx context.Context, reader DocumentCaretReader, doc atsp
 			if !embedded.Valid() {
 				return node, offset, nil
 			}
-			child, ok := nodes[embedded]
+			child, ok := doc.Node(embedded)
 			if !ok || child.Hidden || child.Snapshot.Editable || child.Snapshot.Role == "password text" {
 				return atspi.DocumentNode{}, 0, atspi.ErrNoDocumentCaret
 			}
@@ -70,7 +66,7 @@ func native_caret_node(ctx context.Context, reader DocumentCaretReader, doc atsp
 		if len(node.Children) != 1 {
 			return atspi.DocumentNode{}, 0, atspi.ErrNoDocumentCaret
 		}
-		child, ok := nodes[node.Children[0]]
+		child, ok := doc.Node(node.Children[0])
 		if !ok || child.Hidden || child.Snapshot.Editable || child.Snapshot.CharacterCount != node.Snapshot.CharacterCount {
 			return atspi.DocumentNode{}, 0, atspi.ErrNoDocumentCaret
 		}

internal/review/document_navigation_reader.go

@@ -0,0 +1,46 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package review
+
+import (
+	"context"
+
+	"git.stormux.org/storm/cthulhu/internal/atspi"
+)
+
+// One move owns this wrapper. Validate the path before native reads so stale
+// range lengths and omitted candidates trigger recovery without consuming a
+// different object's text or advancing the retained cursor.
+type navigationTextReader struct {
+	DocumentCaretReader
+	tree        *atspi.AccessibleTree
+	document    atspi.DocumentSnapshot
+	anchor      int
+	readObjects []atspi.ObjectReference
+}
+
+func (reader *navigationTextReader) ReadDocumentCaret(ctx context.Context, object atspi.ObjectReference, offset int, unit atspi.DocumentCaretUnit) (atspi.DocumentCaretText, error) {
+	index, found := reader.document.Index(object.ID())
+	if !found || reader.document.Nodes[index].Reference != object {
+		return atspi.DocumentCaretText{}, atspi.ErrStaleObject
+	}
+	if err := reader.tree.ValidateDocumentRange(ctx, reader.document, reader.anchor, index); err != nil {
+		return atspi.DocumentCaretText{}, err
+	}
+	text, err := reader.DocumentCaretReader.ReadDocumentCaret(ctx, object, offset, unit)
+	if err == nil {
+		reader.readObjects = append(reader.readObjects, object)
+	}
+	return text, err
+}
+
+func (reader *navigationTextReader) did_read(object atspi.ObjectReference) bool {
+	for _, read := range reader.readObjects {
+		if read == object {
+			return true
+		}
+	}
+	return false
+}

internal/review/document_navigation_test.go

@@ -0,0 +1,83 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package review
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"git.stormux.org/storm/cthulhu/internal/atspi"
+)
+
+func TestDocumentCaretDefersUnrelatedUpdatesUntilTraversed(t *testing.T) {
+	for _, test := range []struct {
+		name       string
+		invalidate func(*atspi.AccessibleTree)
+		want       error
+	}{
+		{"text", func(tree *atspi.AccessibleTree) { tree.InvalidateText(webID("/next")) }, atspi.ErrStaleText},
+		{"semantics", func(tree *atspi.AccessibleTree) { tree.InvalidateSnapshot(webID("/next")) }, atspi.ErrStaleSnapshot},
+		{"geometry", func(tree *atspi.AccessibleTree) { tree.InvalidateGeometry(webID("/next")) }, atspi.ErrStaleGeometry},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			reader := caretTextReader{webID("/text"): "Alpha", webID("/next"): "Next"}
+			cursor := newCaretTextCursor(t, reader)
+			test.invalidate(cursor.tree)
+			if _, err := cursor.SyncFocus(context.Background(), webID("/text")); err != nil {
+				t.Fatal("unrelated update blocked focus synchronization", err)
+			}
+			move, err := cursor.MoveCaret(context.Background(), reader, CaretNextCharacter)
+			if err != nil || !move.Moved || move.Text != "l" {
+				t.Fatalf("local character move: %+v %v", move, err)
+			}
+			_, err = cursor.MoveCaret(context.Background(), reader, CaretNextLine)
+			if !errors.Is(err, test.want) {
+				t.Fatalf("dirty target read: %v, want %v", err, test.want)
+			}
+			if place := cursor.places[0]; place.object.ID() != webID("/text") || place.offset != 1 {
+				t.Fatalf("failed move changed position: %+v", place)
+			}
+		})
+	}
+}
+
+func TestDocumentCaretKeepsLocalTextThroughParentInsertion(t *testing.T) {
+	reader := caretTextReader{webID("/text"): "Alpha", webID("/next"): "Next"}
+	cursor := newCaretTextCursor(t, reader)
+	cursor.tree.MarkChildrenChanged(webID("/doc"))
+	move, err := cursor.MoveCaret(context.Background(), reader, CaretNextCharacter)
+	if err != nil || !move.Moved || move.Text != "l" {
+		t.Fatalf("parent insertion blocked live text: %+v %v", move, err)
+	}
+	if _, err := cursor.MoveCaret(context.Background(), reader, CaretNextLine); !errors.Is(err, atspi.ErrIncompleteTree) {
+		t.Fatal("crossed stale child order", err)
+	}
+}
+
+func TestDocumentStructuralMoveDefersUnrelatedBranch(t *testing.T) {
+	nodes := []atspi.TreeNode{
+		{Snapshot: atspi.Snapshot{BusName: webID("/doc").BusName, Path: "/doc", Role: "document web"}, Children: []atspi.ObjectID{webID("/one"), webID("/two"), webID("/later")}},
+		{Snapshot: atspi.Snapshot{BusName: webID("/one").BusName, Path: "/one", Role: "heading", Name: "First"}},
+		{Snapshot: atspi.Snapshot{BusName: webID("/two").BusName, Path: "/two", Role: "heading", Name: "Second"}},
+		{Snapshot: atspi.Snapshot{BusName: webID("/later").BusName, Path: "/later", Role: "static", Name: "Later"}},
+	}
+	tree, err := atspi.NewAccessibleTree(webID("/doc"), nodes)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cursor, _ := NewDocumentCursor(tree)
+	if _, err := cursor.SyncFocus(context.Background(), webID("/one")); err != nil {
+		t.Fatal(err)
+	}
+	tree.InvalidateText(webID("/later"))
+	move, err := cursor.Move(context.Background(), DocumentHeading, 0, false)
+	if err != nil || !move.Moved || move.Position.Object.ID() != webID("/two") {
+		t.Fatalf("unrelated update blocked adjacent heading: %+v %v", move, err)
+	}
+	if _, err := cursor.Move(context.Background(), DocumentHeading, 0, false); !errors.Is(err, atspi.ErrStaleText) {
+		t.Fatal("wrapped across dirty content", err)
+	}
+}

internal/review/document_replacement.go

@@ -14,50 +14,43 @@ func remember_text_parent(doc atspi.DocumentSnapshot, place *documentPlace) {
 	place.textParent = atspi.ObjectReference{}
 	place.textPrevious, place.textNext = atspi.ObjectReference{}, atspi.ObjectReference{}
 	place.recoveryParents = nil
-	// Nodes are in provider preorder. Walking backwards follows the parent
-	// chain in one scan, without rescanning all nodes for each ancestor.
-	var parentID atspi.ObjectID
-	plainText := false
-	for index := len(doc.Nodes) - 1; index >= 0; index-- {
-		node := doc.Nodes[index]
-		if node.Reference == place.object {
-			parentID, plainText = node.Parent, replacement_text_leaf(node)
-			continue
+	node, ok := doc.Node(place.object.ID())
+	if !ok || node.Reference != place.object {
+		return
+	}
+	plainText := replacement_text_leaf(node)
+	for parentID := node.Parent; parentID.Valid(); {
+		parent, ok := doc.Node(parentID)
+		if !ok {
+			break
 		}
-		if !parentID.Valid() || node.Reference.ID() != parentID {
-			continue
-		}
-		if len(place.recoveryParents) == 0 && plainText && replacement_text_parent(node) {
-			place.textParent = node.Reference
-			for childIndex, id := range node.Children {
+		if len(place.recoveryParents) == 0 && plainText && replacement_text_parent(parent) {
+			place.textParent = parent.Reference
+			for childIndex, id := range parent.Children {
 				if id != place.object.ID() {
 					continue
 				}
-				if len(node.Children) == 1 {
-					break
-				}
-				for _, sibling := range doc.Nodes {
-					if childIndex > 0 && sibling.Reference.ID() == node.Children[childIndex-1] {
+				if childIndex > 0 {
+					if sibling, ok := doc.Node(parent.Children[childIndex-1]); ok {
 						place.textPrevious = sibling.Reference
 					}
-					if childIndex+1 < len(node.Children) && sibling.Reference.ID() == node.Children[childIndex+1] {
+				}
+				if childIndex+1 < len(parent.Children) {
+					if sibling, ok := doc.Node(parent.Children[childIndex+1]); ok {
 						place.textNext = sibling.Reference
 					}
-					if (childIndex == 0 || place.textPrevious.Valid()) && (childIndex+1 == len(node.Children) || place.textNext.Valid()) {
-						break
-					}
 				}
-				if childIndex > 0 && !place.textPrevious.Valid() || childIndex+1 < len(node.Children) && !place.textNext.Valid() {
+				if childIndex > 0 && !place.textPrevious.Valid() || childIndex+1 < len(parent.Children) && !place.textNext.Valid() {
 					place.textParent = atspi.ObjectReference{}
 				}
 				break
 			}
 		}
-		if node.Reference == place.document || len(place.recoveryParents) == 32 {
+		if parent.Reference == place.document || len(place.recoveryParents) == 32 {
 			break
 		}
-		place.recoveryParents = append(place.recoveryParents, node.Reference)
-		parentID = node.Parent
+		place.recoveryParents = append(place.recoveryParents, parent.Reference)
+		parentID = parent.Parent
 	}
 }
 

internal/review/document_visual_line.go

@@ -48,9 +48,8 @@ func (reader *visualLineReader) ReadDocumentCaret(ctx context.Context, object at
 	return text, err
 }
 
-func move_caret_line(ctx context.Context, source DocumentCaretReader, tree *atspi.AccessibleTree, doc atspi.DocumentSnapshot, place *documentPlace, indices []caretRange, current int, command DocumentCaretCommand) (DocumentCaretMove, error) {
+func move_caret_line(ctx context.Context, source DocumentCaretReader, tree *atspi.AccessibleTree, doc atspi.DocumentSnapshot, place *documentPlace, indices []caretRange, current int, command DocumentCaretCommand, owners map[int]atspi.ObjectID) (DocumentCaretMove, error) {
 	reader := &visualLineReader{DocumentCaretReader: source, cache: make(map[visualLineKey]atspi.DocumentCaretText)}
-	owners := visual_line_owners(doc.Nodes)
 	next := *place
 	// Move beyond the entire current line, even when character/word movement
 	// left the cursor in a middle fragment or structural navigation chose its

internal/review/document_worker_test.go

@@ -870,7 +870,10 @@ func TestWorkerDocumentRecapturePreservesPosition(t *testing.T) {
 	call := <-capturer.calls
 	call.result <- captureResult{tree: tree}
 	waitResult(t, worker)
-	tree.InvalidateText(webID("/link"))
+	// Only a traversed branch requires recapture now. The hidden heading is
+	// between the current and requested positions; it cannot be skipped until
+	// its invalidated data has been refreshed.
+	tree.InvalidateText(webID("/hidden"))
 	worker.MoveDocument(DocumentHeading, 0, true)
 	call = <-capturer.calls
 	nodes := webNodes()
@@ -889,7 +892,7 @@ func TestWorkerDocumentRecapturePreservesPosition(t *testing.T) {
 		t.Fatalf("recapture diagnostics = %+v", diagnostics)
 	}
 	failed, recovered := diagnostics.Attempts[0], diagnostics.Attempts[1]
-	if failed.Stage != "focus" || failed.Recovery != "document-unresolved" || failed.Error == "" ||
+	if failed.Stage != "move" || failed.Recovery != "preserved" || failed.Error == "" ||
 		recovered.Recovery != "preserved" || recovered.Error != "" || recovered.Before.Object != webID("/second") ||
 		recovered.Synced.Object != webID("/second") || recovered.After.Object != webID("/first") {
 		t.Fatalf("recapture lost diagnostic history: %+v", diagnostics)
@@ -1015,22 +1018,35 @@ func TestDocumentCaretKeepsOffsetAfterDocumentRefresh(t *testing.T) {
 			for _, node := range doc.Nodes {
 				nodes = append(nodes, atspi.TreeNode{Snapshot: node.Snapshot, Children: node.Children, Geometry: node.Geometry, Text: node.Text})
 			}
-			wantReason := atspi.ErrStaleSnapshot
+			var wantReason error = atspi.ErrStaleSnapshot
 			if kind == "children" {
 				cursor.tree.MarkChildrenChanged(webID("/doc"))
-				wantReason = atspi.ErrIncompleteTree
+				wantReason = nil
 			} else {
 				cursor.tree.InvalidateSnapshot(webID("/text"))
 			}
-			go func() {
+			refresh := func() {
 				call := <-navigator.calls
 				err := cursor.tree.Replace(webID("/doc"), nodes)
 				call.result <- captureResult{tree: cursor.tree, err: err}
-			}()
+			}
+			if kind != "children" {
+				go refresh()
+			}
 			result, _ := worker.moveDocumentCaret(ctx, cursor, CaretNextLine, worker.documentEpoch.Load())
 			if result.Err != nil || !errors.Is(result.CaptureReason, wantReason) || result.DocumentCaretText != "Third" {
 				t.Fatalf("semantic refresh restarted or skipped reading: %+v", result)
 			}
+			if kind == "children" {
+				if result.DocumentDiagnostics.CaptureAttempts != 0 {
+					t.Fatal("local text movement recaptured unrelated child order")
+				}
+				go refresh()
+				result, _ = worker.moveDocumentCaret(ctx, cursor, CaretNextLine, worker.documentEpoch.Load())
+				if result.Err != nil || !errors.Is(result.CaptureReason, atspi.ErrIncompleteTree) || result.DocumentCaretText != "End" {
+					t.Fatalf("crossing refreshed children lost position: %+v", result)
+				}
+			}
 		})
 	}
 }