Fix review findings: hostile snapshots, stale async results, trash safety

- snapshot: depth limit (stack overflow in exporters), decompressed-size
  limit (gzip bombs), per-node size cap and saturating aggregation
- export: sanitise exclusion patterns from snapshot metadata
- tui: drop duplicate/trash/filter results that belong to a replaced
  tree; cancel duplicate search on rescan
- trash: refuse symlinked or foreign shared-filesystem trash dirs; never
  overwrite an existing trashed item
- scan: no symlink following without inode identity; correct unscanned
  count and keep real read errors after cancellation

ARCHITECTURE.md

@@ -152,7 +152,9 @@ releases the lock between batches). This is the only lock in the data path.
   own (tiny) size. `same-filesystem` / `all` follow directory symlinks; every
   descended directory's `(dev, inode)` is recorded and a directory already
   visited is never descended twice — loops terminate and nothing is counted
-  twice.
+  twice. On platforms without inode identity (Windows, other portable
+  fallbacks) loop detection is impossible, so symlinks are never followed
+  there and scan info says so.
 * A directory whose device differs from its parent is flagged `MountPoint`.
   With `--one-file-system` it is not descended. On Linux, virtual filesystems
   (proc, sysfs, cgroup, debugfs, …) are never descended — `/proc/kcore` would
@@ -292,9 +294,11 @@ Filenames and snapshot contents are untrusted.
 * Text is clipped by display width (grapheme clusters, East-Asian wide
   characters) so labels never overflow their rectangle.
 * Snapshot decoding validates magic, version, every length, every parent
-  reference (a parent must precede its child, so cycles and recursion are
+  reference (a parent must precede its child, so cycles are impossible),
-  impossible), caps decompressed size and node count, and verifies a SHA-256
+  depth (≤ 4096 levels, bounding recursion in exporters), per-node sizes
-  trailer. Aggregates are recomputed rather than trusted.
+  (≤ 1 EiB) and node count; caps the decompressed body at 64× the file size
+  (decompression bombs fail fast); and verifies a SHA-256 trailer.
+  Aggregates are recomputed with saturating arithmetic rather than trusted.
 * No shell is ever invoked. "Open/reveal" and trash use direct `exec` with
   argument vectors or native APIs; paths are passed as single arguments.
 * `--read-only` disables every mutating action in the UI.

internal/export/export.go

@@ -10,6 +10,7 @@ import (
 	"io"
 	"path/filepath"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/andydixon/mapsize/internal/brand"
@@ -203,7 +204,7 @@ func Summary(w io.Writer, t *inventory.Tree) {
 		}
 	}
 	if st.Excluded > 0 {
-		fmt.Fprintf(w, "Excluded        %s entries (%v)\n", textutil.Count(st.Excluded), st.Excludes)
+		fmt.Fprintf(w, "Excluded        %s entries (%s)\n", textutil.Count(st.Excluded), textutil.Sanitize(strings.Join(st.Excludes, ", ")))
 	}
 	if st.SkippedMounts > 0 {
 		fmt.Fprintf(w, "Other FS skipped %s\n", textutil.Count(st.SkippedMounts))

internal/inventory/tree.go

@@ -8,6 +8,7 @@
 package inventory
 
 import (
+	"math"
 	"path/filepath"
 	"slices"
 	"sync"
@@ -210,6 +211,14 @@ func (t *Tree) Propagate(id NodeID, d Delta) {
 	}
 }
 
+// satAdd adds non-negative int64s, saturating at the maximum.
+func satAdd(a, b int64) int64 {
+	if b > 0 && a > math.MaxInt64-b {
+		return math.MaxInt64
+	}
+	return a + b
+}
+
 func addU32(a uint32, d int64) uint32 {
 	v := int64(a) + d
 	if v < 0 {
@@ -300,23 +309,25 @@ func (t *Tree) Recompute() {
 			*t.dirs.at(n.dir) = [NumCategories]int64{}
 		}
 	}
+	// Sums saturate: snapshot data is untrusted and must not wrap to
+	// negative totals.
 	for i := t.Len() - 1; i > 0; i-- {
 		n := t.Node(NodeID(i))
 		p := t.Node(n.Parent)
-		p.TotSize += n.TotSize
+		p.TotSize = satAdd(p.TotSize, n.TotSize)
-		p.TotAlloc += n.TotAlloc
+		p.TotAlloc = satAdd(p.TotAlloc, n.TotAlloc)
-		p.Errors += n.Errors
+		p.Errors = addU32(p.Errors, int64(n.Errors))
 		cs := t.dirs.at(p.dir)
 		if n.Kind == KindDir {
-			p.Files += n.Files
+			p.Files = addU32(p.Files, int64(n.Files))
-			p.Dirs += n.Dirs + 1
+			p.Dirs = addU32(p.Dirs, int64(n.Dirs)+1)
 			for c, v := range t.dirs.at(n.dir) {
-				cs[c] += v
+				cs[c] = satAdd(cs[c], v)
 			}
 		} else {
-			p.Files++
+			p.Files = addU32(p.Files, 1)
 			if n.Flags&FlagHardlinkDup == 0 {
-				cs[n.Cat] += n.Alloc
+				cs[n.Cat] = satAdd(cs[n.Cat], n.Alloc)
 			}
 		}
 	}

internal/platform/ops_linux.go

@@ -60,11 +60,19 @@ func Trash(path string) error {
 		infoPath = rel
 	}
 	files, info := filepath.Join(trash, "files"), filepath.Join(trash, "info")
-	if err := os.MkdirAll(files, 0o700); err != nil {
+	if trash == home {
-		return err
+		if err := os.MkdirAll(trash, 0o700); err != nil {
+			return err
+		}
+	} else if err := ensurePrivateDir(trash, true); err != nil {
+		// On a shared filesystem another user could plant a symlink or a
+		// world-writable directory here; refuse rather than follow it.
+		return fmt.Errorf("trash directory %s is unsafe: %w", trash, err)
 	}
-	if err := os.MkdirAll(info, 0o700); err != nil {
+	for _, d := range []string{files, info} {
-		return err
+		if err := ensurePrivateDir(d, trash != home); err != nil {
+			return fmt.Errorf("trash directory %s is unsafe: %w", d, err)
+		}
 	}
 	base := filepath.Base(path)
 	for i := 1; i < 10000; i++ {
@@ -72,6 +80,10 @@ func Trash(path string) error {
 		if i > 1 {
 			name = fmt.Sprintf("%s.%d", base, i)
 		}
+		dst := filepath.Join(files, name)
+		if _, err := os.Lstat(dst); err == nil {
+			continue // never overwrite an earlier trashed item (even without .trashinfo)
+		}
 		ip := filepath.Join(info, name+".trashinfo")
 		f, err := os.OpenFile(ip, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o600)
 		if errors.Is(err, os.ErrExist) {
@@ -87,7 +99,7 @@ func Trash(path string) error {
 			os.Remove(ip)
 			return errors.Join(werr, cerr)
 		}
-		if err := os.Rename(path, filepath.Join(files, name)); err != nil {
+		if err := os.Rename(path, dst); err != nil {
 			os.Remove(ip)
 			return err
 		}
@@ -96,6 +108,31 @@ func Trash(path string) error {
 	return errors.New("trash: too many items with the same name")
 }
 
+// ensurePrivateDir creates dir (mode 0700) if missing; an existing entry must
+// be a real directory (not a symlink) owned by us. With strict (trash on a
+// shared filesystem) it must also be inaccessible to others, as the
+// freedesktop.org spec requires; home trash directories made by desktop
+// environments are sometimes 0755, which is harmless there.
+func ensurePrivateDir(dir string, strict bool) error {
+	if err := os.Mkdir(dir, 0o700); err != nil && !errors.Is(err, os.ErrExist) {
+		return err
+	}
+	fi, err := os.Lstat(dir)
+	if err != nil {
+		return err
+	}
+	st := fi.Sys().(*syscall.Stat_t)
+	switch {
+	case !fi.IsDir():
+		return errors.New("not a directory (symlink?)")
+	case int(st.Uid) != os.Getuid():
+		return errors.New("owned by another user")
+	case strict && fi.Mode().Perm()&0o077 != 0:
+		return errors.New("accessible to other users")
+	}
+	return nil
+}
+
 // mountTop returns the top directory of the filesystem containing path.
 func mountTop(path string, dev uint64) string {
 	cur := filepath.Dir(path)

internal/platform/ops_linux_test.go

@@ -42,3 +42,23 @@ func TestTrashFreedesktop(t *testing.T) {
 		t.Fatal("relative paths must be refused")
 	}
 }
+
+func TestEnsurePrivateDirRejectsSymlink(t *testing.T) {
+	base := t.TempDir()
+	target := filepath.Join(base, "attacker")
+	os.Mkdir(target, 0o700)
+	link := filepath.Join(base, ".Trash-1000")
+	os.Symlink(target, link)
+	if err := ensurePrivateDir(link, false); err == nil {
+		t.Fatal("symlinked trash dir accepted")
+	}
+	open := filepath.Join(base, "open")
+	os.Mkdir(open, 0o777)
+	os.Chmod(open, 0o777)
+	if err := ensurePrivateDir(open, true); err == nil {
+		t.Fatal("world-accessible trash dir accepted")
+	}
+	if err := ensurePrivateDir(filepath.Join(base, "fresh"), true); err != nil {
+		t.Fatal(err)
+	}
+}

internal/scan/scan.go

@@ -176,7 +176,13 @@ func Start(ctx context.Context, root string, opts Options) (*Scanner, error) {
 	}
 	t.Stats.Dirs = 1
 	c := &controller{s: s, t: t, opts: opts, links: map[inodeKey]struct{}{}}
-	if opts.Follow != FollowNone {
+	// Loop detection needs inode identity; without it (Windows and other
+	// portable-fallback platforms) symlinks are not followed at all.
+	if opts.Follow != FollowNone && !m.HasIno {
+		c.opts.Follow = FollowNone
+		t.Stats.Follow = "none (no inode identity on this platform)"
+	}
+	if c.opts.Follow != FollowNone {
 		c.visited = map[inodeKey]struct{}{{m.Dev, m.Ino}: {}}
 	}
 	c.rootDev = m.Dev
@@ -271,7 +277,7 @@ func (c *controller) run(ctx context.Context) {
 			}
 			c.t.Lock()
 			for i := range batch {
-				if c.apply(&batch[i], cancelled) {
+				if c.apply(&batch[i]) {
 					inflight--
 				}
 				batch[i] = result{}
@@ -292,7 +298,7 @@ func (c *controller) run(ctx context.Context) {
 	st := &c.t.Stats
 	if cancelled {
 		st.Cancelled = true
-		st.Unscanned = int64(len(c.pending) - c.head)
+		st.Unscanned += int64(len(c.pending) - c.head)
 		for _, p := range c.pending[c.head:] {
 			c.t.Node(p.id).Flags |= inventory.FlagIncomplete
 		}
@@ -352,7 +358,7 @@ func setMeta(n *inventory.Node, m platform.Meta) {
 
 // apply merges one result into the tree. It reports whether the result
 // completed its directory. Called with the tree write-locked.
-func (c *controller) apply(r *result, cancelled bool) bool {
+func (c *controller) apply(r *result) bool {
 	t := c.t
 	j := r.job
 	dir := j.id
@@ -366,7 +372,7 @@ func (c *controller) apply(r *result, cancelled bool) bool {
 		switch {
 		case r.err == nil:
 			dn.Flags |= inventory.FlagScanned
-		case errors.Is(r.err, context.Canceled) || errors.Is(r.err, context.DeadlineExceeded) || cancelled:
+		case errors.Is(r.err, context.Canceled) || errors.Is(r.err, context.DeadlineExceeded):
 			dn.Flags |= inventory.FlagIncomplete
 			t.Stats.Unscanned++
 		default:
@@ -447,7 +453,7 @@ func (c *controller) addEntry(j *job, m platform.Meta, d *inventory.Delta) {
 		case err != nil:
 			st.BrokenLinks++
 			broken = true
-		case tm.Mode.IsDir() && (c.opts.Follow == FollowAll || c.opts.Follow == FollowSameFS && tm.Dev == j.dev):
+		case tm.Mode.IsDir() && tm.HasIno && (c.opts.Follow == FollowAll || c.opts.Follow == FollowSameFS && tm.Dev == j.dev):
 			target, followed = tm, true
 			kind = inventory.KindDir
 		}

internal/snapshot/hostile_test.go

@@ -0,0 +1,131 @@
+package snapshot
+
+import (
+	"bytes"
+	"compress/gzip"
+	"crypto/sha256"
+	"encoding/binary"
+	"io"
+	"strings"
+	"testing"
+
+	"github.com/andydixon/mapsize/internal/brand"
+	"github.com/andydixon/mapsize/internal/export"
+	"github.com/andydixon/mapsize/internal/inventory"
+)
+
+// craft builds a well-formed (correctly checksummed) but hostile snapshot.
+func craft(n int, meta string, rec func(i int, w *writer)) []byte {
+	var out bytes.Buffer
+	out.WriteString(brand.SnapshotMagic)
+	out.Write(binary.LittleEndian.AppendUint16(nil, Version))
+	out.Write(binary.LittleEndian.AppendUint16(nil, flagGzipped))
+	gz, _ := gzip.NewWriterLevel(&out, gzip.BestCompression)
+	h := sha256.New()
+	w := &writer{w: io.MultiWriter(gz, h)}
+	w.uvarint(uint64(len(meta)))
+	w.bytes([]byte(meta))
+	w.uvarint(1)
+	w.str("")
+	w.uvarint(uint64(n))
+	for i := range n {
+		rec(i, w)
+	}
+	w.uvarint(0)
+	gz.Close()
+	out.Write(h.Sum(nil))
+	return out.Bytes()
+}
+
+func node(w *writer, pd uint64, kind inventory.Kind, name string, size int64) {
+	w.uvarint(pd)
+	w.bytes([]byte{byte(kind), 0})
+	w.uvarint(0)
+	w.str(name)
+	w.varint(size)
+	w.varint(size)
+	w.varint(0)
+	for range 5 {
+		w.uvarint(0)
+	}
+}
+
+func chain(n int) []byte {
+	return craft(n, `{"root":"/r"}`, func(i int, w *writer) {
+		if i == 0 {
+			node(w, 0, inventory.KindDir, "", 0)
+		} else {
+			node(w, 1, inventory.KindDir, "a", 0)
+		}
+	})
+}
+
+func TestDeepChainRejected(t *testing.T) {
+	if _, err := Load(bytes.NewReader(chain(MaxDepth + 1))); err != nil {
+		t.Fatalf("depth at the limit must load: %v", err)
+	}
+	_, err := Load(bytes.NewReader(chain(MaxDepth + 2)))
+	if err == nil || !strings.Contains(err.Error(), "deeper") {
+		t.Fatalf("over-deep chain accepted: %v", err)
+	}
+}
+
+func TestDecompressionBombLimited(t *testing.T) {
+	flat := craft(100_000, `{"root":"/r"}`, func(i int, w *writer) {
+		if i == 0 {
+			node(w, 0, inventory.KindDir, "", 0)
+		} else {
+			node(w, uint64(i), inventory.KindFile, "f", 0)
+		}
+	})
+	_, err := LoadLimit(bytes.NewReader(flat), 64<<10)
+	if err == nil || !strings.Contains(err.Error(), "limit") {
+		t.Fatalf("bomb not limited: %v", err)
+	}
+	if got := bodyLimit(int64(len(flat))); got < 64<<20 {
+		t.Fatalf("bodyLimit floor: %d", got)
+	}
+}
+
+func TestHugeSizesDoNotWrap(t *testing.T) {
+	data := craft(3, `{"root":"/r"}`, func(i int, w *writer) {
+		if i == 0 {
+			node(w, 0, inventory.KindDir, "", 0)
+		} else {
+			node(w, uint64(i), inventory.KindFile, "f", MaxSize)
+		}
+	})
+	tr, err := Load(bytes.NewReader(data))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if tr.Node(0).TotSize < 0 {
+		t.Fatal("aggregate wrapped negative")
+	}
+	over := craft(2, `{"root":"/r"}`, func(i int, w *writer) {
+		if i == 0 {
+			node(w, 0, inventory.KindDir, "", 0)
+		} else {
+			node(w, 1, inventory.KindFile, "f", MaxSize+1)
+		}
+	})
+	if _, err := Load(bytes.NewReader(over)); err == nil {
+		t.Fatal("size above MaxSize accepted")
+	}
+}
+
+func TestHostileMetadataSanitisedInSummary(t *testing.T) {
+	data := craft(1, `{"root":"/r\u001b[2J","excludes":["\u001b]0;PWNED\u0007"],"excluded":1}`, func(i int, w *writer) {
+		node(w, 0, inventory.KindDir, "", 0)
+	})
+	tr, err := Load(bytes.NewReader(data))
+	if err != nil {
+		t.Fatal(err)
+	}
+	tr.Stats.Excluded = 1
+	var b bytes.Buffer
+	export.Summary(&b, tr)
+	if strings.ContainsAny(b.String(), "\x1b\x07") {
+		t.Fatalf("raw control characters in summary: %q", b.String())
+	}
+}

internal/snapshot/snapshot.go

@@ -47,13 +47,18 @@ const Version = 1
 
 // Limits applied when reading untrusted snapshots.
 const (
-	MaxNodes    = 1<<31 - 1
+	MaxNodes = 1<<31 - 1
-	MaxNameLen  = 1 << 16
+	MaxDepth = 4096    // far beyond any real path; bounds recursion in exporters
-	MaxMetaLen  = 16 << 20
+	MaxSize  = 1 << 60 // per-node size cap (1 EiB); keeps aggregates from overflowing
-	MaxExtLen   = 64
+	// DefaultMaxBody caps the decompressed body for Load. LoadFile uses a
-	MaxMsgLen   = 4096
+	// limit proportional to the file size instead (see bodyLimit).
-	maxExts     = 1<<16 - 1
+	DefaultMaxBody = 4 << 30
-	flagGzipped = 1
+	MaxNameLen     = 1 << 16
+	MaxMetaLen     = 16 << 20
+	MaxExtLen      = 64
+	MaxMsgLen      = 4096
+	maxExts        = 1<<16 - 1
+	flagGzipped    = 1
 )
 
 type meta struct {
@@ -305,8 +310,35 @@ func (r *reader) str(max uint64, what string) string {
 	return string(r.bytesN(r.uvarint(max, what+" length")))
 }
 
-// Load reads and validates a snapshot.
+// limitedReader fails (rather than silently truncating) past n bytes, so a
-func Load(in io.Reader) (*inventory.Tree, error) {
+// decompression bomb is reported as such.
+type limitedReader struct {
+	r io.Reader
+	n int64
+}
+
+func (l *limitedReader) Read(p []byte) (int, error) {
+	if l.n <= 0 {
+		return 0, errors.New("snapshot: decompressed size exceeds limit (possible decompression bomb)")
+	}
+	if int64(len(p)) > l.n {
+		p = p[:l.n]
+	}
+	n, err := l.r.Read(p)
+	l.n -= int64(n)
+	return n, err
+}
+
+// bodyLimit allows decompressed bodies up to 64× the compressed file size
+// (real snapshots compress ~6×), with a 64 MiB floor for tiny files.
+func bodyLimit(fileSize int64) int64 { return max(64<<20, fileSize*64) }
+
+// Load reads and validates a snapshot, allowing up to DefaultMaxBody bytes
+// of decompressed data.
+func Load(in io.Reader) (*inventory.Tree, error) { return LoadLimit(in, DefaultMaxBody) }
+
+// LoadLimit is Load with an explicit decompressed-size limit.
+func LoadLimit(in io.Reader, maxBody int64) (*inventory.Tree, error) {
 	br := bufio.NewReaderSize(in, 1<<20)
 	hdr := make([]byte, len(brand.SnapshotMagic)+4)
 	if _, err := io.ReadFull(br, hdr); err != nil {
@@ -333,7 +365,7 @@ func Load(in io.Reader) (*inventory.Tree, error) {
 	pr, pw := io.Pipe()
 	defer pr.Close() // unblocks the copier if we bail out early
 	go func() {
-		_, err := io.CopyBuffer(pw, io.TeeReader(gz, h), make([]byte, 256<<10))
+		_, err := io.CopyBuffer(pw, io.TeeReader(&limitedReader{gz, maxBody}, h), make([]byte, 256<<10))
 		pw.CloseWithError(err)
 	}()
 	r := &reader{r: bufio.NewReaderSize(pr, 1<<16)}
@@ -358,6 +390,7 @@ func Load(in io.Reader) (*inventory.Tree, error) {
 	}
 	extIndex := t.ExtIndexer()
 	nNodes := r.uvarint(MaxNodes, "node count")
+	depth := []uint16{0} // per node, for the depth limit; parents precede children
 	if nNodes == 0 {
 		return nil, errors.New("snapshot: no root node")
 	}
@@ -380,8 +413,8 @@ func Load(in io.Reader) (*inventory.Tree, error) {
 			r.fail("node %d: invalid kind/category", i)
 			break
 		}
-		if size < 0 || alloc < 0 {
+		if size < 0 || alloc < 0 || size > MaxSize || alloc > MaxSize {
-			r.fail("node %d: negative size", i)
+			r.fail("node %d: size out of range", i)
 			break
 		}
 		var id inventory.NodeID
@@ -407,7 +440,12 @@ func Load(in io.Reader) (*inventory.Tree, error) {
 				r.fail("node %d: invalid name %q", i, name)
 				break
 			}
+			if d := depth[parent] + 1; d > MaxDepth {
+				r.fail("node %d: deeper than %d levels", i, MaxDepth)
+				break
+			}
 			id = t.Add(parent, name, kind)
+			depth = append(depth, depth[parent]+1)
 		}
 		n := t.Node(id)
 		n.Cat, n.Flags = cat, flags
@@ -469,5 +507,9 @@ func LoadFile(path string) (*inventory.Tree, error) {
 		return nil, err
 	}
 	defer f.Close()
-	return Load(f)
+	limit := int64(DefaultMaxBody)
+	if fi, err := f.Stat(); err == nil {
+		limit = bodyLimit(fi.Size())
+	}
+	return LoadLimit(f, limit)
 }

internal/tui/actions.go

@@ -17,8 +17,9 @@ import (
 // ---- Trash ---------------------------------------------------------------
 
 type trashDoneMsg struct {
-	id  inventory.NodeID
+	tree *inventory.Tree // the tree id belongs to; results for a replaced tree are dropped
-	err error
+	id   inventory.NodeID
+	err  error
 }
 
 // requestTrash asks for confirmation before moving the selection to the
@@ -49,7 +50,8 @@ func (m *Model) requestTrash() tea.Cmd {
 			"", "It will be moved to the " + platform.TrashName + ", not permanently deleted."},
 		yes: "move to " + platform.TrashName,
 		onYes: func(m *Model) tea.Cmd {
-			return func() tea.Msg { return trashDoneMsg{id, platform.Trash(path)} }
+			t := m.tree
+			return func() tea.Msg { return trashDoneMsg{t, id, platform.Trash(path)} }
 		},
 	})
 	return nil
@@ -59,6 +61,10 @@ func (m *Model) trashDone(msg trashDoneMsg) tea.Cmd {
 	if msg.err != nil {
 		return m.warn("Trash failed: " + textutil.Sanitize(msg.err.Error()))
 	}
+	if msg.tree != m.tree || m.scanning {
+		// A rescan replaced the inventory; the new scan reflects the change.
+		return m.info("Moved to " + platform.TrashName)
+	}
 	// The scan has finished, so the UI goroutine is the tree's only writer.
 	t := m.tree
 	t.Lock()
@@ -96,6 +102,7 @@ type dupState struct {
 type (
 	dupProgressMsg struct{}
 	dupDoneMsg     struct {
+		finder *duplicate.Finder // identifies the search; stale results are dropped
 		groups []duplicate.Group
 		err    error
 	}
@@ -128,7 +135,7 @@ func (m *Model) startDuplicates() tea.Cmd {
 			t := m.tree
 			return tea.Batch(m.startTicking(), func() tea.Msg {
 				g, err := f.Find(ctx, t, duplicate.Options{MinSize: 1, Workers: 4})
-				return dupDoneMsg{g, err}
+				return dupDoneMsg{f, g, err}
 			})
 		},
 	})
@@ -147,7 +154,7 @@ func (m *Model) ensureDupView() {
 }
 
 func (m *Model) dupMsg(msg tea.Msg) tea.Cmd {
-	if d, ok := msg.(dupDoneMsg); ok && m.dups != nil {
+	if d, ok := msg.(dupDoneMsg); ok && m.dups != nil && d.finder == m.dups.finder {
 		m.dups.running = false
 		m.dups.groups, m.dups.err = d.groups, d.err
 		m.dirty = true

internal/tui/model.go

@@ -378,10 +378,22 @@ func (m *Model) rescan() tea.Cmd {
 	m.scanner, m.tree, m.cancel, m.scanning, m.ctrlC = s, t, cancel, s != nil, false
 	m.zoom, m.sel = t.Root(), noSel
 	m.kidsCache = map[inventory.NodeID]*kids{}
-	m.dups = nil
+	if m.dups != nil {
+		m.dups.cancel()
+		m.dups = nil
+		// Drop the duplicates view: its rows referred to the old tree.
+		for i, v := range m.views {
+			if _, ok := v.(*dupView); ok {
+				m.views = append(m.views[:i], m.views[i+1:]...)
+				m.view = 0
+				break
+			}
+		}
+	}
 	m.search.result = nil
+	m.search.gen++ // results computed against the old tree are discarded
 	m.invalidate()
-	return tea.Batch(waitScan(s), m.startTicking(), m.info("Rescanning…"))
+	return tea.Batch(waitScan(s), m.startTicking(), m.info("Rescanning…"), m.applyFilter())
 }
 
 // resolvePendingZoom re-zooms into the remembered directory once the new