fix(windows): release FFmpeg memory and capture native crashes

Co-authored-by: xunguangzlj-cloud <[email protected]>

.github/workflows/test.yml

@@ -134,6 +134,9 @@ jobs:
         if: runner.os == 'macOS'
         with:
           flutter-version: ${{ env.FLUTTER_VERSION }}
+      - name: Test Windows FFmpeg memory and stream lifecycle
+        if: runner.os == 'Windows'
+        run: go test -v -count=1 -timeout 180s ./pkg/download/engine/ffmpeg ./pkg/download/engine/inject/stream ./pkg/download/engine
       - name: Install Linux WebView dependencies
         if: runner.os == 'Linux'
         run: |

internal/fetcher/fetcher.go

@@ -46,6 +46,10 @@ type Uploader interface {
 	WaitUpload() error
 }
 
+type DownloadCounter interface {
+	ReceivedBytes() int64
+}
+
 // FetcherMeta defines the meta information of a fetcher.
 type FetcherMeta struct {
 	Req  *base.Request  `json:"req"`

internal/protocol/bt/download_test.go

@@ -290,6 +290,82 @@ func TestBTDownloadSelectedFiles(t *testing.T) {
 	if f.Meta().Res.Size != 48*1024 {
 		t.Fatal("selected resource size is incorrect")
 	}
+	if downloaded := f.Progress().TotalDownloaded(); downloaded != 48*1024 || f.ReceivedBytes() <= downloaded {
+		t.Fatalf("selected progress = %d, received traffic = %d; want 48 KiB of progress and traffic across the shared piece", downloaded, f.ReceivedBytes())
+	}
+}
+
+func TestBTProgressOnlyCountsVerifiedFileBytes(t *testing.T) {
+	const fileSize = 56 * 1024
+	fixture := makeBTFixtureWithPieceSize(t, map[string][]byte{
+		"a.bin": btPayload(fileSize, "verified-a"),
+		"b.bin": btPayload(fileSize, "verified-b"),
+	}, 16*1024, false, true, 64*1024)
+	f := btDownloadFetcher(t, nil)
+	btResolve(t, f, fixture.Magnet)
+	dir := t.TempDir()
+	f.Meta().Opts = &base.Options{Path: dir}
+	btStart(t, f)
+	deadline := time.Now().Add(8 * time.Second)
+	for f.torrent.Files()[0].BytesCompleted() == 0 && time.Now().Before(deadline) {
+		time.Sleep(10 * time.Millisecond)
+	}
+	btPause(t, f)
+	if f.torrent.Files()[0].BytesCompleted() == 0 || f.torrent.Piece(0).State().Complete {
+		t.Fatal("expected some received bytes in a piece that is still incomplete")
+	}
+	if f.ReceivedBytes() == 0 {
+		t.Fatal("received traffic must be visible before a piece is verified")
+	}
+	if progress := f.Progress(); len(progress) != 2 || progress[0] != 0 {
+		t.Errorf("progress before the first file's piece is verified = %v, want zero for the first file", progress)
+	}
+	fixture.Limiter.SetLimit(rate.Inf)
+	btStart(t, f)
+	btAwaitDone(t, f)
+	fixture.AssertFiles(t, dir)
+	progress := f.Progress()
+	if len(progress) != 2 || progress[0] != fileSize || progress[1] != fileSize {
+		t.Fatalf("verified progress at completion = %v, want %d for each file", progress, fileSize)
+	}
+}
+
+func TestBTUploadedBytesSamplesLiveTraffic(t *testing.T) {
+	payload := btPayload(48*1024, "upload-counter")
+	fixture := newBTFixture(t, map[string][]byte{"": payload}, 0)
+	const saved = 1024
+	f := &Fetcher{
+		torrent:       fixture.Torrent,
+		data:          &fetcherData{SeedBytes: saved},
+		seedBaseBytes: saved,
+	}
+	f.torrentReady.Store(true)
+	f.torrentUpload.Store(true)
+
+	cfg := torrent.TestingConfig(t)
+	cfg.DataDir = t.TempDir()
+	cfg.DisableTrackers = true
+	cfg.DisableUTP = true
+	cfg.DisableIPv6 = true
+	peer, err := torrent.NewClient(cfg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { peer.Close() })
+	download, _, err := peer.AddTorrentSpec(torrent.TorrentSpecFromMetaInfo(fixture.MetaInfo))
+	if err != nil {
+		t.Fatal(err)
+	}
+	download.AddPeers([]torrent.PeerInfo{{Addr: fixture.Seeder.ListenAddrs()[0]}})
+	download.DownloadAll()
+	select {
+	case <-download.Complete().On():
+	case <-time.After(10 * time.Second):
+		t.Fatal("loopback peer did not complete")
+	}
+	if got, want := f.UploadedBytes(), int64(saved+len(payload)); got != want {
+		t.Fatalf("uploaded bytes = %d, want %d including the saved bytes", got, want)
+	}
 }
 
 func TestBTPauseAndResume(t *testing.T) {

internal/protocol/bt/fetcher.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"sort"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -45,6 +46,7 @@ type Fetcher struct {
 	torrent       *torrent.Torrent
 	meta          *fetcher.FetcherMeta
 	data          *fetcherData
+	seedBaseBytes int64
 
 	torrentReady    atomic.Bool
 	torrentUpload   atomic.Bool
@@ -463,14 +465,46 @@ func (f *Fetcher) Progress() fetcher.Progress {
 	if !f.torrentReady.Load() {
 		return append(fetcher.Progress(nil), f.data.Progress...)
 	}
+	pieceSize := f.torrent.Info().PieceLength
+	var offset int64
+	var verified []verifiedByteRange
+	for _, run := range f.torrent.PieceStateRuns() {
+		end := offset + int64(run.Length)*pieceSize
+		if pieceVerified(run.PieceState) {
+			verified = append(verified, verifiedByteRange{start: offset, end: end})
+		}
+		offset = end
+	}
+	files := f.torrent.Files()
 	for i := range f.data.Progress {
 		selectIndex := f.meta.Opts.SelectFiles[i]
-		file := f.torrent.Files()[selectIndex]
+		file := files[selectIndex]
-		f.data.Progress[i] = file.BytesCompleted()
+		f.data.Progress[i] = verifiedFileBytes(verified, file.Offset(), file.Length())
 	}
 	return append(fetcher.Progress(nil), f.data.Progress...)
 }
 
+type verifiedByteRange struct {
+	start, end int64
+}
+
+func verifiedFileBytes(verified []verifiedByteRange, offset, length int64) int64 {
+	first := sort.Search(len(verified), func(i int) bool { return verified[i].end > offset })
+	fileEnd := offset + length
+	var completed int64
+	for _, run := range verified[first:] {
+		if run.start >= fileEnd {
+			break
+		}
+		completed += min(fileEnd, run.end) - max(offset, run.start)
+	}
+	return completed
+}
+
+func pieceVerified(state torrent.PieceState) bool {
+	return state.Ok && state.Complete && !state.Hashing && !state.QueuedForHash
+}
+
 func (f *Fetcher) Wait() error {
 	f.mu.Lock()
 	var closed <-chan struct{}
@@ -587,7 +621,7 @@ func (f *Fetcher) isDoneLocked() bool {
 		file := f.torrent.Files()[index]
 		for i := file.BeginPieceIndex(); i < file.EndPieceIndex(); i++ {
 			state := f.torrent.Piece(i).State()
-			if !state.Ok || !state.Complete || state.Hashing || state.QueuedForHash {
+			if !pieceVerified(state) {
 				return false
 			}
 		}
@@ -685,11 +719,13 @@ func (f *Fetcher) Upload() (err error) {
 }
 
 func (f *Fetcher) doUpload(fromUpload bool) {
+	f.mu.Lock()
 	if !f.torrentUpload.CompareAndSwap(false, true) {
+		f.mu.Unlock()
 		return
 	}
-	f.mu.Lock()
+	f.seedBaseBytes = f.data.SeedBytes
-	initialBytes, initialTime := f.data.SeedBytes, f.data.SeedTime
+	initialTime := f.data.SeedTime
 	torrentClosed := f.torrent.Closed()
 	f.mu.Unlock()
 	var doneTime int64
@@ -707,8 +743,7 @@ func (f *Fetcher) doUpload(fromUpload bool) {
 				f.mu.Unlock()
 				continue
 			}
-			stats := f.torrentStats()
+			f.refreshSeedBytesLocked()
-			f.data.SeedBytes = initialBytes + stats.BytesWrittenData.Int64()
 			if !fromUpload && !f.isDoneLocked() {
 				f.mu.Unlock()
 				continue
@@ -741,9 +776,27 @@ func (f *Fetcher) torrentStats() torrent.TorrentStats {
 func (f *Fetcher) UploadedBytes() int64 {
 	f.mu.Lock()
 	defer f.mu.Unlock()
+	if f.torrentReady.Load() && f.torrentUpload.Load() {
+		f.refreshSeedBytesLocked()
+	}
 	return f.data.SeedBytes
 }
 
+func (f *Fetcher) refreshSeedBytesLocked() {
+	stats := f.torrentStats()
+	f.data.SeedBytes = max(f.data.SeedBytes, f.seedBaseBytes+stats.BytesWrittenData.Int64())
+}
+
+func (f *Fetcher) ReceivedBytes() int64 {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if !f.torrentReady.Load() {
+		return 0
+	}
+	stats := f.torrentStats()
+	return stats.BytesReadUsefulData.Int64()
+}
+
 func (f *Fetcher) WaitUpload() (err error) {
 	<-f.uploadDoneCh
 	return nil

internal/protocol/bt/fixture_test.go

@@ -46,6 +46,11 @@ func newBTHybridFixture(t testing.TB, payload []byte) *btFixture {
 }
 
 func makeBTFixture(t testing.TB, files map[string][]byte, bytesPerSecond int, v2, private bool) *btFixture {
+	t.Helper()
+	return makeBTFixtureWithPieceSize(t, files, bytesPerSecond, v2, private, 16*1024)
+}
+
+func makeBTFixtureWithPieceSize(t testing.TB, files map[string][]byte, bytesPerSecond int, v2, private bool, pieceSize int64) *btFixture {
 	t.Helper()
 	source := t.TempDir()
 	name := "payload.bin"
@@ -64,7 +69,7 @@ func makeBTFixture(t testing.TB, files map[string][]byte, bytesPerSecond int, v2
 		}
 		expected[filepath.Join(name, filepath.FromSlash(path))] = append([]byte(nil), data...)
 	}
-	info := metainfo.Info{PieceLength: 16 * 1024}
+	info := metainfo.Info{PieceLength: pieceSize}
 	if err := info.BuildFromFilePath(root); err != nil {
 		t.Fatal(err)
 	}

pkg/download/crash_log_test.go

@@ -0,0 +1,26 @@
+package download
+
+import (
+	"os"
+	"path/filepath"
+	"runtime/debug"
+	"testing"
+)
+
+func TestLogPanicPreservesPreviousCrash(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "crash.log")
+	const previous = "previous crash traceback\n"
+	if err := os.WriteFile(path, []byte(previous), 0600); err != nil {
+		t.Fatal(err)
+	}
+	logPanic(dir)
+	t.Cleanup(func() { _ = debug.SetCrashOutput(nil, debug.CrashOptions{}) })
+	data, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(data) != previous {
+		t.Fatalf("previous crash was overwritten: %q", data)
+	}
+}

pkg/download/downloader.go

@@ -345,7 +345,12 @@ func (d *Downloader) Setup() error {
 						}
 
 						current := task.fetcher.Progress().TotalDownloaded()
-						delta := current - task.Progress.Downloaded
+						delta := max(0, current-task.Progress.Downloaded)
+						if counter, ok := task.fetcher.(fetcher.DownloadCounter); ok && task.Status == base.DownloadStatusRunning {
+							received := counter.ReceivedBytes()
+							delta = received - task.receivedBytes
+							task.receivedBytes = received
+						}
 						if task.Meta != nil && task.Meta.Req != nil {
 							if producer := d.blob.Production(task.Meta.Req.URL); producer != nil {
 								downloaded, received := producer.Progress()
@@ -353,19 +358,20 @@ func (d *Downloader) Setup() error {
 									task.producer = producer
 									task.producerReceived = 0
 									task.speedArr = nil
+									task.downloadSampledAt = time.Time{}
 								}
 								current = downloaded
 								delta = max(0, received-task.producerReceived)
 								task.producerReceived = received
 							}
 						}
-						tick := float64(d.cfg.RefreshInterval) / 1000
 						downloadDataChanged := false
 						uploading := task.Uploading
 						if task.Status == base.DownloadStatusRunning {
 							downloadDataChanged = current != task.Progress.Downloaded
 							task.Progress.Used = task.timer.Used()
-							task.Progress.Speed = task.updateSpeed(max(0, delta), tick)
+							elapsed := sampleSeconds(&task.downloadSampledAt, time.Now())
+							task.Progress.Speed = task.updateSpeed(delta, elapsed)
 							task.Progress.Downloaded = current
 						}
 
@@ -374,7 +380,8 @@ func (d *Downloader) Setup() error {
 							uploader := task.fetcher.(fetcher.Uploader)
 							currentUploaded := uploader.UploadedBytes()
 							uploadDataChanged = currentUploaded != task.Progress.Uploaded
-							task.Progress.UploadSpeed = task.updateUploadSpeed(currentUploaded-task.Progress.Uploaded, tick)
+							elapsed := sampleSeconds(&task.uploadSampledAt, time.Now())
+							task.Progress.UploadSpeed = task.updateUploadSpeed(currentUploaded-task.Progress.Uploaded, elapsed)
 							task.Progress.Uploaded = currentUploaded
 						}
 						task.statusLock.Unlock()
@@ -2453,6 +2460,8 @@ func (d *Downloader) doStart(task *Task) (err error) {
 			return nil
 		}
 		task.Progress.Speed = 0
+		task.speedArr = nil
+		task.downloadSampledAt = time.Time{}
 		task.timer.Start()
 		task.statusLock.Unlock()
 		if err := task.fetcher.Start(); err != nil {
@@ -2650,11 +2659,12 @@ func logPanic(logDir string) {
 	if err := util.CreateDirIfNotExist(logDir); err != nil {
 		return
 	}
-	f, err := os.Create(filepath.Join(logDir, "crash.log"))
+	f, err := os.OpenFile(filepath.Join(logDir, "crash.log"), os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600)
 	if err != nil {
 		return
 	}
-	debug.SetCrashOutput(f, debug.CrashOptions{})
+	defer f.Close() // SetCrashOutput duplicates the descriptor.
+	_ = debug.SetCrashOutput(f, debug.CrashOptions{})
 }
 
 func (d *Downloader) assignFetcherManager(task *Task) error {
@@ -3061,8 +3071,10 @@ func initTask(task *Task) {
 	task.lock = &sync.Mutex{}
 	task.statsLock = &sync.Mutex{}
 	task.blobRefLock = &sync.Mutex{}
-	task.speedArr = make([]int64, 0)
+	task.speedArr = nil
-	task.uploadSpeedArr = make([]int64, 0)
+	task.uploadSpeedArr = nil
+	task.downloadSampledAt = time.Time{}
+	task.uploadSampledAt = time.Time{}
 }
 
 func (d *Downloader) releaseBlobTask(task *Task) {

pkg/download/engine/ffmpeg/README.md

@@ -174,3 +174,12 @@ compilation memory, host buffers and JS allocations are additional to the
 linear-memory limit. Playback support depends on the selected codecs, not just
 the `.mp4` suffix. Platform execution and performance must be tested on target
 devices, especially mobile/32-bit devices.
+
+On 64-bit Windows, instance linear memory uses a reserved virtual address range with
+pages committed as it grows. Module completion, errors and cancellation release
+this range directly through `VirtualFree`, rather than waiting for Go's garbage
+collector to reclaim large buffers. Growing an instance preserves its address
+without copying the previous buffer. The 512 MiB limit is unchanged; reservation
+does not commit that entire amount. Shared compilation remains resident after
+the first merge, so process memory is not expected to return exactly to the
+pre-FFmpeg baseline. This does not diagnose unrelated idle memory growth.

pkg/download/engine/ffmpeg/memory.go

@@ -0,0 +1,32 @@
+package ffmpeg
+
+import (
+	"context"
+	"sync"
+
+	"github.com/tetratelabs/wazero/experimental"
+)
+
+// The runtime does not always invoke Free when a module's start function traps.
+// Keep host ownership until execution returns, including failed instantiation.
+func withOwnedMemory(ctx context.Context, allocator experimental.MemoryAllocator) (context.Context, func()) {
+	var memories []*ownedLinearMemory
+	ctx = experimental.WithMemoryAllocator(ctx, experimental.MemoryAllocatorFunc(
+		func(cap, max uint64) experimental.LinearMemory {
+			memory := &ownedLinearMemory{LinearMemory: allocator.Allocate(cap, max)}
+			memories = append(memories, memory)
+			return memory
+		}))
+	return ctx, func() {
+		for _, memory := range memories {
+			memory.Free()
+		}
+	}
+}
+
+type ownedLinearMemory struct {
+	experimental.LinearMemory
+	once sync.Once
+}
+
+func (m *ownedLinearMemory) Free() { m.once.Do(m.LinearMemory.Free) }

pkg/download/engine/ffmpeg/memory_other.go

@@ -0,0 +1,7 @@
+//go:build !windows || (!amd64 && !arm64)
+
+package ffmpeg
+
+import "context"
+
+func withLinearMemory(ctx context.Context) (context.Context, func()) { return ctx, func() {} }

pkg/download/engine/ffmpeg/memory_test.go

@@ -0,0 +1,88 @@
+package ffmpeg
+
+import (
+	"context"
+	"encoding/hex"
+	"testing"
+	"time"
+
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/experimental"
+)
+
+// Verify the pinned runtime's allocator lifecycle on every development host:
+// host-owned buffers must not be released before execution ends, or retained
+// after failed instantiation, traps or cancellation.
+func TestLinearMemoryModuleLifecycle(t *testing.T) {
+	testLinearMemoryModuleLifecycle(t, func(_, _ uint64) experimental.LinearMemory {
+		return &testLinearMemory{}
+	})
+}
+
+type testLinearMemory struct{ buffer []byte }
+
+func (m *testLinearMemory) Reallocate(size uint64) []byte {
+	m.buffer = append(m.buffer, make([]byte, int(size)-len(m.buffer))...)
+	return m.buffer
+}
+func (m *testLinearMemory) Free() { m.buffer = nil }
+
+type trackedLinearMemory struct {
+	experimental.LinearMemory
+	freeCount int
+}
+
+func (m *trackedLinearMemory) Free() {
+	m.freeCount++
+	m.LinearMemory.Free()
+}
+
+func testLinearMemoryModuleLifecycle(t *testing.T, allocate experimental.MemoryAllocatorFunc) {
+	t.Helper()
+	for _, tt := range []struct {
+		name string
+		// A module with one memory (min=1/max=2 pages), optionally a start
+		// function that traps or loops until its context is cancelled.
+		wasm    string
+		wantErr bool
+	}{
+		{"close", "0061736d01000000050401010102", false},
+		{"trap", "0061736d01000000010401600000030201000504010101020801000a05010300000b", true},
+		{"cancel", "0061736d01000000010401600000030201000504010101020801000a0901070003400c000b0b", true},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+			defer cancel()
+			var memory *trackedLinearMemory
+			ctx, release := withOwnedMemory(ctx, experimental.MemoryAllocatorFunc(
+				func(_, max uint64) experimental.LinearMemory {
+					memory = &trackedLinearMemory{LinearMemory: allocate(0, max)}
+					return memory
+				}))
+			defer release()
+			rt := wazero.NewRuntimeWithConfig(ctx, wazero.NewRuntimeConfig().WithCloseOnContextDone(true))
+			defer rt.Close(context.Background())
+			binary, err := hex.DecodeString(tt.wasm)
+			if err != nil {
+				t.Fatal(err)
+			}
+			module, err := rt.Instantiate(ctx, binary)
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("instantiate: %v", err)
+			}
+			if !tt.wantErr {
+				if memory == nil || memory.freeCount != 0 {
+					t.Fatal("module did not allocate native memory")
+				}
+				if err := module.Close(ctx); err != nil {
+					t.Fatal(err)
+				}
+			}
+			release()
+			release()
+			if memory == nil || memory.freeCount != 1 {
+				t.Fatal("host did not release memory exactly once")
+			}
+		})
+	}
+}

pkg/download/engine/ffmpeg/memory_windows.go

@@ -0,0 +1,70 @@
+//go:build windows && (amd64 || arm64)
+
+package ffmpeg
+
+import (
+	"context"
+	"fmt"
+	"unsafe"
+
+	"github.com/tetratelabs/wazero/experimental"
+	"golang.org/x/sys/windows"
+)
+
+// Keep large, short-lived WASM buffers out of the Go heap. Closing a module
+// releases its committed pages immediately, without waiting for GC/scavenging.
+func withLinearMemory(ctx context.Context) (context.Context, func()) {
+	return withOwnedMemory(ctx, experimental.MemoryAllocatorFunc(
+		func(_, max uint64) experimental.LinearMemory {
+			return &windowsLinearMemory{max: max}
+		}))
+}
+
+// Reserve the address range once, committing zero-filled pages on demand. This
+// avoids both copying the previous buffer and temporarily retaining two large
+// Go allocations when memory.grow runs. The backing address never changes.
+type windowsLinearMemory struct {
+	address uintptr
+	max     uint64
+	size    uint64
+	freed   bool
+}
+
+func (m *windowsLinearMemory) Reallocate(size uint64) []byte {
+	if m.freed || size > m.max || m.max > uint64(^uint(0)>>1) {
+		return nil
+	}
+	if size == 0 {
+		return []byte{}
+	}
+	if m.address == 0 {
+		address, err := windows.VirtualAlloc(0, uintptr(m.max), windows.MEM_RESERVE, windows.PAGE_READWRITE)
+		if err != nil {
+			panic(fmt.Errorf("ffmpeg: reserve WASM memory: %w", err))
+		}
+		m.address = address
+	}
+	if size > m.size {
+		_, err := windows.VirtualAlloc(m.address, uintptr(size), windows.MEM_COMMIT, windows.PAGE_READWRITE)
+		if err != nil {
+			if m.size == 0 {
+				// Instantiation cannot proceed without the minimum memory. Wazero
+				// has not taken ownership yet, so release the reservation here.
+				m.Free()
+				panic(fmt.Errorf("ffmpeg: commit WASM memory: %w", err))
+			}
+			return nil // memory.grow reports failure to the guest.
+		}
+		m.size = size
+	}
+	return unsafe.Slice((*byte)(unsafe.Pointer(m.address)), int(size))
+}
+
+func (m *windowsLinearMemory) Free() {
+	if m.address != 0 {
+		_ = windows.VirtualFree(m.address, 0, windows.MEM_RELEASE)
+		m.address = 0
+	}
+	m.size = 0
+	m.freed = true
+}

pkg/download/engine/ffmpeg/memory_windows_test.go

@@ -0,0 +1,54 @@
+//go:build windows && (amd64 || arm64)
+
+package ffmpeg
+
+import (
+	"testing"
+	"unsafe"
+
+	"github.com/tetratelabs/wazero/experimental"
+	"golang.org/x/sys/windows"
+)
+
+func TestWindowsLinearMemoryGrowthAndRelease(t *testing.T) {
+	const page = 65536
+	m := &windowsLinearMemory{max: 4 * page}
+	defer m.Free()
+	first := m.Reallocate(page)
+	if len(first) != page {
+		t.Fatalf("initial allocation: %d", len(first))
+	}
+	first[0], first[page-1] = 17, 29
+	address := m.address
+	grown := m.Reallocate(3 * page)
+	if unsafe.SliceData(first) != unsafe.SliceData(grown) || grown[0] != 17 || grown[page-1] != 29 {
+		t.Fatal("growing memory moved or lost existing bytes")
+	}
+	for _, b := range grown[page:] {
+		if b != 0 {
+			t.Fatal("newly committed memory is not zero-filled")
+		}
+	}
+	if m.Reallocate(5*page) != nil || m.address != address || m.size != 3*page {
+		t.Fatal("failed growth changed the existing allocation")
+	}
+	m.Free()
+	m.Free()
+	if m.address != 0 || m.Reallocate(page) != nil {
+		t.Fatal("freed memory can still be used")
+	}
+	var info windows.MemoryBasicInformation
+	if err := windows.VirtualQuery(address, &info, unsafe.Sizeof(info)); err != nil {
+		t.Fatal(err)
+	}
+	const memFree = 0x10000 // MEMORY_BASIC_INFORMATION.State: MEM_FREE.
+	if info.State != memFree {
+		t.Fatalf("pages remain reserved after Free: state=%x", info.State)
+	}
+}
+
+func TestWindowsLinearMemoryModuleLifecycle(t *testing.T) {
+	testLinearMemoryModuleLifecycle(t, func(_, max uint64) experimental.LinearMemory {
+		return &windowsLinearMemory{max: max}
+	})
+}

pkg/download/engine/ffmpeg/runtime.go

@@ -151,7 +151,9 @@ func RunAcquired(ctx context.Context, video, audio Input, out io.Writer, format
 	files := &inputFS{files: map[string]Input{"video": video, "audio": audio}}
 	fsconfig := wazero.NewFSConfig().(sysfs.FSConfig).WithSysFSMount(files, "/inputs")
 	logs := &tailLog{}
-	rc, err := wasm.Run(ctx, shared.runtime, shared.module, wasm.Args{
+	runCtx, freeMemory := withLinearMemory(ctx)
+	defer freeMemory()
+	rc, err := wasm.Run(runCtx, shared.runtime, shared.module, wasm.Args{
 		Name: "ffmpeg", Args: args, Stdout: out, Stderr: logs,
 		Config: func(c wazero.ModuleConfig) wazero.ModuleConfig { return c.WithFSConfig(fsconfig) },
 	})

pkg/download/model.go

@@ -87,8 +87,11 @@ type Task struct {
 	blobRefLock       *sync.Mutex
 	blobURL           string
 	runGeneration     uint64
-	speedArr       []int64
+	speedArr          []speedSample
-	uploadSpeedArr []int64
+	uploadSpeedArr    []speedSample
+	downloadSampledAt time.Time
+	uploadSampledAt   time.Time
+	receivedBytes     int64
 }
 
 // TaskRuntimeStatus is the lightweight, frequently refreshed view of a task.
@@ -195,7 +198,21 @@ func (t *Task) updateUploadSpeed(downloaded int64, usedTime float64) int64 {
 	return calcSpeed(&t.uploadSpeedArr, downloaded, usedTime)
 }
 
-func calcSpeed(speedArr *[]int64, downloaded int64, usedTime float64) int64 {
+type speedSample struct {
+	bytes   int64
+	seconds float64
+}
+
+func sampleSeconds(lastSample *time.Time, now time.Time) float64 {
+	previous := *lastSample
+	*lastSample = now
+	if previous.IsZero() {
+		return 0
+	}
+	return now.Sub(previous).Seconds()
+}
+
+func calcSpeed(speedArr *[]speedSample, downloaded int64, usedTime float64) int64 {
 	if usedTime <= 0 {
 		return 0
 	}
@@ -204,18 +221,18 @@ func calcSpeed(speedArr *[]int64, downloaded int64, usedTime float64) int64 {
 		return 0
 	}
 
-	*speedArr = append(*speedArr, downloaded)
+	*speedArr = append(*speedArr, speedSample{bytes: downloaded, seconds: usedTime})
-	// Record last 5 seconds of download speed to calculate the average speed
-	if len(*speedArr) > int(5.0/usedTime) {
-		*speedArr = (*speedArr)[1:]
-	}
-
 	var total int64
-	for _, v := range *speedArr {
+	var elapsed float64
-		total += v
+	first := len(*speedArr)
+	for first > 0 && elapsed < 5 {
+		first--
+		sample := (*speedArr)[first]
+		total += sample.bytes
+		elapsed += sample.seconds
 	}
-
+	*speedArr = (*speedArr)[first:]
-	return int64(float64(total) / float64(len(*speedArr)) / usedTime)
+	return int64(float64(total) / elapsed)
 }
 
 type TaskFilter struct {

pkg/download/model_test.go

@@ -1,9 +1,32 @@
 package download
 
-import "testing"
+import (
+	"testing"
+	"time"
+)
+
+func TestTransferSpeedWithUnevenSamples(t *testing.T) {
+	var task Task
+	for _, sample := range []struct {
+		bytes   int64
+		seconds float64
+	}{
+		{1000, 1},
+		{2000, 2},
+		{4000, 4},
+		{6000, 6},
+	} {
+		if got := task.updateSpeed(sample.bytes, sample.seconds); got != 1000 {
+			t.Errorf("download speed after %v seconds = %d, want 1000", sample.seconds, got)
+		}
+		if got := task.updateUploadSpeed(sample.bytes, sample.seconds); got != 1000 {
+			t.Errorf("upload speed after %v seconds = %d, want 1000", sample.seconds, got)
+		}
+	}
+}
 
 func TestCalcSpeedResetOnRollback(t *testing.T) {
-	speedArr := []int64{1024, 2048, 4096}
+	speedArr := []speedSample{{1024, 1}, {2048, 1}, {4096, 1}}
 
 	if got := calcSpeed(&speedArr, -512, 1); got != 0 {
 		t.Fatalf("calcSpeed() = %d, want 0 after rollback", got)
@@ -16,3 +39,17 @@ func TestCalcSpeedResetOnRollback(t *testing.T) {
 		t.Fatalf("calcSpeed() = %d, want 1024 after reset", got)
 	}
 }
+
+func TestSampleSecondsUsesThePreviousSuccessfulSample(t *testing.T) {
+	start := time.Now()
+	var last time.Time
+	if got := sampleSeconds(&last, start); got != 0 {
+		t.Fatalf("first sample elapsed = %v, want 0", got)
+	}
+	if got := sampleSeconds(&last, start.Add(1500*time.Millisecond)); got != 1.5 {
+		t.Fatalf("elapsed after a delayed sample = %v, want 1.5", got)
+	}
+	if got := sampleSeconds(&last, start.Add(2*time.Second)); got != 0.5 {
+		t.Fatalf("elapsed after the next sample = %v, want 0.5", got)
+	}
+}

ui/flutter/lib/features/settings/application/settings_controller.dart

@@ -19,12 +19,6 @@ class SettingsState {
   }
 }
 
-class SettingsSaveResult {
-  const SettingsSaveResult({required this.btRestartRequired});
-
-  final bool btRestartRequired;
-}
-
 class SettingsController extends AsyncNotifier<SettingsState> {
   Future<void> _saveTail = Future<void>.value();
   int _saveRevision = 0;
@@ -42,7 +36,7 @@ class SettingsController extends AsyncNotifier<SettingsState> {
     state = AsyncValue.data(SettingsState(config: config));
   }
 
-  Future<SettingsSaveResult> save(DownloaderConfig config) {
+  Future<void> save(DownloaderConfig config) {
     final snapshot = DownloaderConfig.fromJson(config.toJson());
     final revision = ++_saveRevision;
     state = AsyncValue.data(SettingsState(config: config, saving: true));
@@ -53,15 +47,10 @@ class SettingsController extends AsyncNotifier<SettingsState> {
     return result;
   }
 
-  Future<SettingsSaveResult> _save(DownloaderConfig config, int revision) async {
+  Future<void> _save(DownloaderConfig config, int revision) async {
     try {
       final service = ref.read(gopeedServiceProvider);
       final latest = await service.getConfig();
-      final previousBt = (
-        latest.protocolConfig.bt.listenPort,
-        latest.protocolConfig.bt.disableDht,
-        latest.protocolConfig.bt.disablePex,
-      );
       config.extra
         ..windowState = latest.extra.windowState
         ..bookmarks = latest.extra.bookmarks
@@ -75,12 +64,6 @@ class SettingsController extends AsyncNotifier<SettingsState> {
         ref.read(appRuntimeControllerProvider.notifier).replaceDownloaderConfig(saved);
         if (revision == _saveRevision) state = AsyncValue.data(SettingsState(config: saved));
       }
-      final savedBt = (
-        saved.protocolConfig.bt.listenPort,
-        saved.protocolConfig.bt.disableDht,
-        saved.protocolConfig.bt.disablePex,
-      );
-      return SettingsSaveResult(btRestartRequired: previousBt != savedBt);
     } finally {
       if (ref.mounted && revision == _saveRevision && state.value?.saving == true) {
         state = AsyncValue.data(state.requireValue.copyWith(saving: false));

ui/flutter/lib/features/settings/presentation/pages/settings_page.dart

@@ -625,6 +625,7 @@ class _SettingsPageState extends ConsumerState<SettingsPage> {
                   ),
                   SettingsItem(
                     title: context.l10n.enableDht,
+                    subtitle: context.l10n.restartRequired,
                     child: shad.Switch(
                       value: !config.protocolConfig.bt.disableDht,
                       onChanged: (value) => _mutateConfig((next) => next.protocolConfig.bt.disableDht = !value),
@@ -632,6 +633,7 @@ class _SettingsPageState extends ConsumerState<SettingsPage> {
                   ),
                   SettingsItem(
                     title: context.l10n.enablePex,
+                    subtitle: context.l10n.restartRequired,
                     child: shad.Switch(
                       value: !config.protocolConfig.bt.disablePex,
                       onChanged: (value) => _mutateConfig((next) => next.protocolConfig.bt.disablePex = !value),
@@ -1202,10 +1204,7 @@ class _SettingsPageState extends ConsumerState<SettingsPage> {
     final snapshot = DownloaderConfig.fromJson(config.toJson());
     _loadedSignature = _signature(snapshot);
     try {
-      final result = await ref.read(settingsControllerProvider.notifier).save(snapshot);
+      await ref.read(settingsControllerProvider.notifier).save(snapshot);
-      if (mounted && result.btRestartRequired) {
-        _toast(context.l10n.restartRequired, type: AppToastType.info);
-      }
       return true;
     } catch (error) {
       if (mounted) _toast(error.toString());

ui/flutter/lib/features/tasks/presentation/pages/create_task_window_page.dart

@@ -41,7 +41,6 @@ import '../../application/pending_download.dart';
 import '../../application/task_list_navigation.dart';
 import '../widgets/history_search_field.dart';
 import '../widgets/create_task_action_buttons.dart';
-import '../widgets/create_task_advanced_toggle.dart';
 import '../widgets/resolve_download_dialog.dart';
 
 class CreateTaskWindowPage extends ConsumerStatefulWidget {
@@ -561,11 +560,20 @@ class _CreateTaskWindowPageState extends ConsumerState<CreateTaskWindowPage> {
                     ),
                     const SizedBox(height: 20),
                     Align(
-                      alignment: AlignmentDirectional.centerStart,
+                      alignment: Alignment.centerLeft,
-                      child: CreateTaskAdvancedToggle(
+                      child: GestureDetector(
-                        key: const ValueKey('create-task-advanced-toggle'),
+                        onTap: _toggleAdvanced,
-                        expanded: _showAdvanced,
+                        child: Row(
-                        onPressed: _toggleAdvanced,
+                          mainAxisSize: MainAxisSize.min,
+                          children: [
+                            Text(
+                              context.l10n.advanced,
+                              style: TextStyle(color: palette.textPrimary, fontSize: 14, fontWeight: FontWeight.w600),
+                            ),
+                            const SizedBox(width: 8),
+                            _TripleChevronIcon(expanded: _showAdvanced, color: palette.textSecondary),
+                          ],
+                        ),
                       ),
                     ),
                     AnimatedCrossFade(
@@ -1925,6 +1933,30 @@ class _MiniInputAction extends StatelessWidget {
   }
 }
 
+class _TripleChevronIcon extends StatelessWidget {
+  const _TripleChevronIcon({required this.expanded, required this.color});
+
+  final bool expanded;
+  final Color color;
+
+  @override
+  Widget build(BuildContext context) {
+    final icon = expanded ? Icons.expand_less : Icons.expand_more;
+    return SizedBox(
+      width: 14,
+      height: 18,
+      child: Stack(
+        clipBehavior: Clip.none,
+        children: [
+          Positioned(top: 0, left: 0, child: Icon(icon, size: 14, color: color)),
+          Positioned(top: 4, left: 0, child: Icon(icon, size: 14, color: color)),
+          Positioned(top: 8, left: 0, child: Icon(icon, size: 14, color: color)),
+        ],
+      ),
+    );
+  }
+}
+
 class _SegmentButton extends StatelessWidget {
   const _SegmentButton({required this.label, required this.active, required this.onTap});
 

ui/flutter/lib/features/tasks/presentation/widgets/create_task_advanced_toggle.dart

@@ -1,49 +0,0 @@
-import 'package:shadcn_flutter/shadcn_flutter.dart';
-
-import '../../../../l10n/l10n.dart';
-import '../../../../shared/theme/app_design_tokens.dart';
-import '../../../../shared/theme/app_palette.dart';
-
-/// A quiet disclosure control with the same keyboard behavior as other buttons.
-class CreateTaskAdvancedToggle extends StatelessWidget {
-  const CreateTaskAdvancedToggle({super.key, required this.expanded, required this.onPressed});
-
-  final bool expanded;
-  final VoidCallback onPressed;
-
-  @override
-  Widget build(BuildContext context) {
-    final palette = AppPalette.of(context);
-    final reduceMotion = MediaQuery.disableAnimationsOf(context);
-    return Semantics(
-      expanded: expanded,
-      child: ButtonStyleOverride.inherit(
-        padding: (context, states, value) => const EdgeInsets.symmetric(vertical: AppDesignTokens.space12),
-        child: GhostButton(
-          onPressed: onPressed,
-          child: ConstrainedBox(
-            constraints: const BoxConstraints(minHeight: 20),
-            child: Row(
-              mainAxisSize: MainAxisSize.min,
-              children: [
-                Flexible(
-                  child: Text(
-                    context.l10n.advanced,
-                    style: TextStyle(color: palette.textPrimary, fontSize: 14, fontWeight: FontWeight.w600),
-                  ),
-                ),
-                const SizedBox(width: AppDesignTokens.space8),
-                AnimatedRotation(
-                  turns: expanded ? 0.5 : 0,
-                  duration: reduceMotion ? Duration.zero : const Duration(milliseconds: 180),
-                  curve: Curves.easeOutCubic,
-                  child: Icon(Icons.keyboard_arrow_down, size: 16, color: palette.textSecondary),
-                ),
-              ],
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}

ui/flutter/lib/l10n/app_ar.arb

@@ -208,7 +208,7 @@
   "categoryName": "اسم الفئة",
   "categoryPath": "مسار الفئة",
   "autoCategorizeByExtension": "تصنيف تلقائي حسب نوع الملف",
-  "autoCategorizeByExtensionDescription": "توجيه التنزيلات إلى مجلد الفئة تلقائيًا حسب امتداد الملف عند الحفظ في مجلد التنزيل الافتراضي",
+  "autoCategorizeByExtensionDescription": "توجيه التنزيلات إلى مجلد الفئة تلقائيًا حسب امتداد الملف عند الحفظ في مجلد التنزيل الافتراضي.",
   "categoryExtensions": "امتدادات الملفات",
   "categoryExtensionsUsageHint": "افصل الامتدادات بفواصل أو مسافات ثم اضغط Enter.",
   "categoryExtensionsEmptyHint": "بدون الامتدادات، لن تُحفظ الملفات في هذا التصنيف تلقائيًا.",

ui/flutter/lib/l10n/app_az.arb

@@ -215,7 +215,7 @@
   "categoryName": "Kateqoriyanın Adı",
   "categoryPath": "Kateqoriyanın Yolu",
   "autoCategorizeByExtension": "Fayl tipinə görə avtomatik kateqoriyalaşdırma",
-  "autoCategorizeByExtensionDescription": "Standart yükləmə qovluğuna yadda saxlanarkən yükləmələr fayl uzantısına görə avtomatik olaraq kateqoriya qovluğuna yönləndirilir",
+  "autoCategorizeByExtensionDescription": "Standart yükləmə qovluğuna yadda saxlanarkən yükləmələr fayl uzantısına görə avtomatik olaraq kateqoriya qovluğuna yönləndirilir.",
   "categoryExtensions": "Fayl uzantıları",
   "categoryExtensionsUsageHint": "Uzantıları vergül və ya boşluqla ayırın, sonra Enter-a basın.",
   "categoryExtensionsEmptyHint": "Uzantı yoxdursa, fayllar bu kateqoriyaya avtomatik olaraq saxlanmır.",

ui/flutter/lib/l10n/app_ca.arb

@@ -208,7 +208,7 @@
   "categoryName": "Nom de la categoria",
   "categoryPath": "Ruta de la categoria",
   "autoCategorizeByExtension": "Categoritza automàticament segons el tipus de fitxer",
-  "autoCategorizeByExtensionDescription": "Les baixades es desen a la carpeta de categoria segons l'extensió del fitxer en utilitzar la carpeta de baixades predeterminada",
+  "autoCategorizeByExtensionDescription": "Les baixades es desen a la carpeta de categoria segons l'extensió del fitxer en utilitzar la carpeta de baixades predeterminada.",
   "categoryExtensions": "Extensions de fitxer",
   "categoryExtensionsUsageHint": "Separa les extensions amb comes o espais i prem Retorn.",
   "categoryExtensionsEmptyHint": "Sense extensions, els fitxers no es desaran aquí automàticament.",

ui/flutter/lib/l10n/app_de.arb

@@ -208,7 +208,7 @@
   "categoryName": "Kategoriename",
   "categoryPath": "Kategoriepfad",
   "autoCategorizeByExtension": "Nach Dateityp automatisch kategorisieren",
-  "autoCategorizeByExtensionDescription": "Downloads werden beim Speichern im Standard-Download-Ordner anhand der Dateiendung automatisch einem Kategorieordner zugeordnet",
+  "autoCategorizeByExtensionDescription": "Downloads werden beim Speichern im Standard-Download-Ordner anhand der Dateiendung automatisch einem Kategorieordner zugeordnet.",
   "categoryExtensions": "Dateiendungen",
   "categoryExtensionsUsageHint": "Trenne Endungen mit Kommas oder Leerzeichen und drücke Enter.",
   "categoryExtensionsEmptyHint": "Ohne Endungen werden Dateien nicht automatisch dieser Kategorie zugeordnet.",

ui/flutter/lib/l10n/app_en.arb

@@ -222,7 +222,7 @@
   "categoryName": "Category Name",
   "categoryPath": "Category Path",
   "autoCategorizeByExtension": "Auto-categorize by file type",
-  "autoCategorizeByExtensionDescription": "Automatically route downloads into a category folder based on the file name when saving to the default download folder",
+  "autoCategorizeByExtensionDescription": "Automatically route downloads into a category folder based on the file name when saving to the default download folder.",
   "categoryExtensions": "Associated Extensions",
   "categoryExtensionsUsageHint": "Separate suffixes with commas or spaces, then press Enter.",
   "categoryExtensionsEmptyHint": "Without extensions, files won't be saved into this category automatically.",

ui/flutter/lib/l10n/app_es.arb

@@ -208,7 +208,7 @@
   "categoryName": "Nombre de categoría",
   "categoryPath": "Ruta de categoría",
   "autoCategorizeByExtension": "Categorizar automáticamente por tipo de archivo",
-  "autoCategorizeByExtensionDescription": "Las descargas se guardan automáticamente en la carpeta de categoría según la extensión del archivo al usar la carpeta de descargas predeterminada",
+  "autoCategorizeByExtensionDescription": "Las descargas se guardan automáticamente en la carpeta de categoría según la extensión del archivo al usar la carpeta de descargas predeterminada.",
   "categoryExtensions": "Extensiones de archivo",
   "categoryExtensionsUsageHint": "Separa las extensiones con comas o espacios y pulsa Intro.",
   "categoryExtensionsEmptyHint": "Sin extensiones, los archivos no se guardarán automáticamente en esta categoría.",

ui/flutter/lib/l10n/app_fa.arb

@@ -208,7 +208,7 @@
   "categoryName": "نام دسته‌بندی",
   "categoryPath": "مسیر دسته‌بندی",
   "autoCategorizeByExtension": "دسته‌بندی خودکار بر اساس نوع فایل",
-  "autoCategorizeByExtensionDescription": "هنگام ذخیره در پوشه پیش‌فرض دانلود، دانلودها بر اساس پسوند فایل به پوشه دسته مربوطه منتقل می‌شوند",
+  "autoCategorizeByExtensionDescription": "هنگام ذخیره در پوشه پیش‌فرض دانلود، دانلودها بر اساس پسوند فایل به پوشه دسته مربوطه منتقل می‌شوند.",
   "categoryExtensions": "پسوندهای فایل",
   "categoryExtensionsUsageHint": "پسوندها را با ویرگول یا فاصله جدا کنید و Enter را بزنید.",
   "categoryExtensionsEmptyHint": "بدون پسوندها، فایل‌ها به‌صورت خودکار در این دسته ذخیره نمی‌شوند.",

ui/flutter/lib/l10n/app_fr.arb

@@ -208,7 +208,7 @@
   "categoryName": "Nom de la catégorie",
   "categoryPath": "Chemin de la catégorie",
   "autoCategorizeByExtension": "Catégoriser automatiquement selon le type de fichier",
-  "autoCategorizeByExtensionDescription": "Les téléchargements sont placés dans un dossier de catégorie selon l'extension du fichier lors de l'enregistrement dans le dossier de téléchargement par défaut",
+  "autoCategorizeByExtensionDescription": "Les téléchargements sont placés dans un dossier de catégorie selon l'extension du fichier lors de l'enregistrement dans le dossier de téléchargement par défaut.",
   "categoryExtensions": "Extensions de fichier",
   "categoryExtensionsUsageHint": "Séparez les extensions par virgules ou espaces, puis appuyez sur Entrée.",
   "categoryExtensionsEmptyHint": "Sans extensions, les fichiers ne seront pas enregistrés ici automatiquement.",

ui/flutter/lib/l10n/app_hu.arb

@@ -208,7 +208,7 @@
   "categoryName": "Kategória neve",
   "categoryPath": "Kategória útvonala",
   "autoCategorizeByExtension": "Automatikus kategorizálás fájltípus szerint",
-  "autoCategorizeByExtensionDescription": "Az alapértelmezett letöltési mappa használatakor a letöltések a fájl kiterjesztése alapján automatikusan a kategória mappájába kerülnek",
+  "autoCategorizeByExtensionDescription": "Az alapértelmezett letöltési mappa használatakor a letöltések a fájl kiterjesztése alapján automatikusan a kategória mappájába kerülnek.",
   "categoryExtensions": "Fájlkiterjesztések",
   "categoryExtensionsUsageHint": "A kiterjesztéseket vesszővel vagy szóközzel válaszd el, majd nyomd le az Enter billentyűt.",
   "categoryExtensionsEmptyHint": "Kiterjesztések nélkül a fájlok nem kerülnek automatikusan ebbe a kategóriába.",

ui/flutter/lib/l10n/app_id.arb

@@ -208,7 +208,7 @@
   "categoryName": "Nama Kategori",
   "categoryPath": "Path Kategori",
   "autoCategorizeByExtension": "Kategorikan otomatis berdasarkan jenis file",
-  "autoCategorizeByExtensionDescription": "Unduhan dialihkan ke folder kategori berdasarkan ekstensi file saat disimpan ke folder unduhan bawaan",
+  "autoCategorizeByExtensionDescription": "Unduhan dialihkan ke folder kategori berdasarkan ekstensi file saat disimpan ke folder unduhan bawaan.",
   "categoryExtensions": "Ekstensi file",
   "categoryExtensionsUsageHint": "Pisahkan ekstensi dengan koma atau spasi, lalu tekan Enter.",
   "categoryExtensionsEmptyHint": "Tanpa ekstensi, file tidak akan otomatis disimpan ke kategori ini.",

ui/flutter/lib/l10n/app_it.arb

@@ -208,7 +208,7 @@
   "categoryName": "Nome categoria",
   "categoryPath": "Percorso categoria",
   "autoCategorizeByExtension": "Categorizza automaticamente per tipo di file",
-  "autoCategorizeByExtensionDescription": "Il download viene instradato automaticamente nella cartella della categoria in base all'estensione quando si salva nella cartella di download predefinita",
+  "autoCategorizeByExtensionDescription": "Il download viene instradato automaticamente nella cartella della categoria in base all'estensione quando si salva nella cartella di download predefinita.",
   "categoryExtensions": "Estensioni file",
   "categoryExtensionsUsageHint": "Separa le estensioni con virgole o spazi e premi Invio.",
   "categoryExtensionsEmptyHint": "Senza estensioni, i file non verranno salvati qui automaticamente.",

ui/flutter/lib/l10n/app_ja.arb

@@ -208,7 +208,7 @@
   "categoryName": "カテゴリ名",
   "categoryPath": "カテゴリパス",
   "autoCategorizeByExtension": "ファイル種別で自動分類",
-  "autoCategorizeByExtensionDescription": "既定のダウンロードフォルダーに保存する際、拡張子に基づいて分類フォルダーへ自動的に振り分けます",
+  "autoCategorizeByExtensionDescription": "既定のダウンロードフォルダーに保存する際、拡張子に基づいて分類フォルダーへ自動的に振り分けます。",
   "categoryExtensions": "ファイル拡張子",
   "categoryExtensionsUsageHint": "カンマやスペースで拡張子を区切り、Enterで追加します。",
   "categoryExtensionsEmptyHint": "拡張子が未設定の場合、ファイルは自動的にこの分類へ保存されません。",

ui/flutter/lib/l10n/app_ko.arb

@@ -208,7 +208,7 @@
   "categoryName": "카테고리 이름",
   "categoryPath": "카테고리 경로",
   "autoCategorizeByExtension": "파일 형식별 자동 분류",
-  "autoCategorizeByExtensionDescription": "기본 다운로드 폴더에 저장할 때 확장자에 따라 분류 폴더로 자동 이동합니다",
+  "autoCategorizeByExtensionDescription": "기본 다운로드 폴더에 저장할 때 확장자에 따라 분류 폴더로 자동 이동합니다.",
   "categoryExtensions": "파일 확장자",
   "categoryExtensionsUsageHint": "쉼표나 공백으로 확장자를 구분하고 Enter를 눌러 추가하세요.",
   "categoryExtensionsEmptyHint": "확장자가 없으면 파일이 이 분류로 자동 저장되지 않습니다.",

ui/flutter/lib/l10n/app_pl.arb

@@ -208,7 +208,7 @@
   "categoryName": "Nazwa kategorii",
   "categoryPath": "Ścieżka kategorii",
   "autoCategorizeByExtension": "Automatyczna kategorizacja według typu pliku",
-  "autoCategorizeByExtensionDescription": "Pobierane pliki są automatycznie zapisywane w folderze kategorii na podstawie rozszerzenia, gdy używany jest domyślny folder pobierania",
+  "autoCategorizeByExtensionDescription": "Pobierane pliki są automatycznie zapisywane w folderze kategorii na podstawie rozszerzenia, gdy używany jest domyślny folder pobierania.",
   "categoryExtensions": "Rozszerzenia plików",
   "categoryExtensionsUsageHint": "Rozdzielaj rozszerzenia przecinkami lub spacjami i naciskaj Enter.",
   "categoryExtensionsEmptyHint": "Bez rozszerzeń pliki nie będą automatycznie zapisywane w tej kategorii.",

ui/flutter/lib/l10n/app_pt.arb

@@ -208,7 +208,7 @@
   "categoryName": "Nome da Categoria",
   "categoryPath": "Caminho da Categoria",
   "autoCategorizeByExtension": "Categorizar automaticamente por tipo de arquivo",
-  "autoCategorizeByExtensionDescription": "Envia os downloads para a pasta da categoria com base na extensão ao salvar na pasta de download padrão",
+  "autoCategorizeByExtensionDescription": "Envia os downloads para a pasta da categoria com base na extensão ao salvar na pasta de download padrão.",
   "categoryExtensions": "Extensões de arquivo",
   "categoryExtensionsUsageHint": "Separe as extensões com vírgulas ou espaços e prima Enter.",
   "categoryExtensionsEmptyHint": "Sem extensões, os ficheiros não serão guardados aqui automaticamente.",

ui/flutter/lib/l10n/app_ru.arb

@@ -208,7 +208,7 @@
   "categoryName": "Название категории",
   "categoryPath": "Путь категории",
   "autoCategorizeByExtension": "Автокатегоризация по типу файла",
-  "autoCategorizeByExtensionDescription": "Загрузки автоматически сохраняются в папку категории по расширению файла, если выбрана папка загрузки по умолчанию",
+  "autoCategorizeByExtensionDescription": "Загрузки автоматически сохраняются в папку категории по расширению файла, если выбрана папка загрузки по умолчанию.",
   "categoryExtensions": "Расширения файлов",
   "categoryExtensionsUsageHint": "Разделяйте расширения запятыми или пробелами и нажимайте Enter.",
   "categoryExtensionsEmptyHint": "Без расширений файлы не будут автоматически сохранены в эту категорию.",

ui/flutter/lib/l10n/app_sk.arb

@@ -222,7 +222,7 @@
   "categoryName": "Názov kategórie",
   "categoryPath": "Cesta kategórie",
   "autoCategorizeByExtension": "Automatická kategorizácia podľa typu súboru",
-  "autoCategorizeByExtensionDescription": "Sťahovania sa pri ukladaní do predvoleného priečinka sťahovania automaticky presúvajú do priečinka kategórie podľa prípony súboru",
+  "autoCategorizeByExtensionDescription": "Sťahovania sa pri ukladaní do predvoleného priečinka sťahovania automaticky presúvajú do priečinka kategórie podľa prípony súboru.",
   "categoryExtensions": "Prípony súborov",
   "categoryExtensionsUsageHint": "Oddeľujte prípony čiarkami alebo medzerami a stlačte Enter.",
   "categoryExtensionsEmptyHint": "Bez prípon sa súbory automaticky neuložia do tejto kategórie.",

ui/flutter/lib/l10n/app_ta.arb

@@ -208,7 +208,7 @@
   "categoryName": "வகை பெயர்",
   "categoryPath": "வகை பாதை",
   "autoCategorizeByExtension": "கோப்பு வகை வாரியாக தானாக வகைப்படுத்து",
-  "autoCategorizeByExtensionDescription": "இயல்புநிலை பதிவிறக்கக் கோப்புறையில் சேமிக்கும்போது, கோப்பு நீட்டிப்பின் அடிப்படையில் வகைக் கோப்புறைக்கு தானாக அனுப்பப்படும்",
+  "autoCategorizeByExtensionDescription": "இயல்புநிலை பதிவிறக்கக் கோப்புறையில் சேமிக்கும்போது, கோப்பு நீட்டிப்பின் அடிப்படையில் வகைக் கோப்புறைக்கு தானாக அனுப்பப்படும்.",
   "categoryExtensions": "கோப்பு நீட்டிப்புகள்",
   "categoryExtensionsUsageHint": "நீட்டிப்புகளை காற்புள்ளிகள் அல்லது இடைவெளிகளால் பிரித்து Enter அழுத்தவும்.",
   "categoryExtensionsEmptyHint": "நீட்டிப்புகள் இல்லாததால், கோப்புகள் இந்த வகைப்பாட்டில் தானாகச் சேமிக்கப்படாது.",

ui/flutter/lib/l10n/app_tr.arb

@@ -208,7 +208,7 @@
   "categoryName": "Kategori Adı",
   "categoryPath": "Kategori Yolu",
   "autoCategorizeByExtension": "Dosya tipine göre otomatik sınıflandır",
-  "autoCategorizeByExtensionDescription": "Varsayılan indirme klasörüne kaydedilirken dosya uzantısına göre ilgili klasöre otomatik yönlendirir",
+  "autoCategorizeByExtensionDescription": "Varsayılan indirme klasörüne kaydedilirken dosya uzantısına göre ilgili klasöre otomatik yönlendirir.",
   "categoryExtensions": "Dosya uzantıları",
   "categoryExtensionsUsageHint": "Sonekleri virgül veya boşlukla ayırıp Enter'a basın.",
   "categoryExtensionsEmptyHint": "Uzantı yoksa dosyalar bu kategoriye otomatik olarak kaydedilmez.",

ui/flutter/lib/l10n/app_uk.arb

@@ -208,7 +208,7 @@
   "categoryName": "Назва категорії",
   "categoryPath": "Шлях категорії",
   "autoCategorizeByExtension": "Автокатегоризація за типом файлу",
-  "autoCategorizeByExtensionDescription": "Завантаження автоматично зберігаються в папку категорії за розширенням файлу, якщо вибрано папку завантаження за замовчуванням",
+  "autoCategorizeByExtensionDescription": "Завантаження автоматично зберігаються в папку категорії за розширенням файлу, якщо вибрано папку завантаження за замовчуванням.",
   "categoryExtensions": "Розширення файлів",
   "categoryExtensionsUsageHint": "Розділяйте розширення комами або пробілами та натискайте Enter.",
   "categoryExtensionsEmptyHint": "Без розширень файли не зберігатимуться в цю категорію автоматично.",

ui/flutter/lib/l10n/app_vi.arb

@@ -208,7 +208,7 @@
   "categoryName": "Tên danh mục",
   "categoryPath": "Đường dẫn danh mục",
   "autoCategorizeByExtension": "Tự động phân loại theo loại tệp",
-  "autoCategorizeByExtensionDescription": "Tải xuống sẽ được chuyển vào thư mục danh mục dựa trên phần mở rộng tệp khi lưu vào thư mục tải xuống mặc định",
+  "autoCategorizeByExtensionDescription": "Tải xuống sẽ được chuyển vào thư mục danh mục dựa trên phần mở rộng tệp khi lưu vào thư mục tải xuống mặc định.",
   "categoryExtensions": "Phần mở rộng tệp",
   "categoryExtensionsUsageHint": "Phân tách phần mở rộng bằng dấu phẩy hoặc khoảng trắng rồi nhấn Enter.",
   "categoryExtensionsEmptyHint": "Không có phần mở rộng, tệp sẽ không tự động được lưu vào danh mục này.",

ui/flutter/lib/l10n/app_zh.arb

@@ -208,7 +208,7 @@
   "categoryName": "分类名称",
   "categoryPath": "分类路径",
   "autoCategorizeByExtension": "按文件类型自动分类",
-  "autoCategorizeByExtensionDescription": "保存到默认下载目录时，根据文件后缀自动归入对应分类文件夹",
+  "autoCategorizeByExtensionDescription": "保存到默认下载目录时，根据文件后缀自动归入对应分类文件夹。",
   "categoryExtensions": "文件后缀关联",
   "categoryExtensionsUsageHint": "支持逗号/空格分隔后缀，按回车添加。",
   "categoryExtensionsEmptyHint": "未设置后缀，文件不会自动归入此分类。",

ui/flutter/lib/l10n/app_zh_TW.arb

@@ -208,7 +208,7 @@
   "categoryName": "分類名稱",
   "categoryPath": "分類路徑",
   "autoCategorizeByExtension": "按檔案類型自動分類",
-  "autoCategorizeByExtensionDescription": "儲存至預設下載目錄時，根據檔案副檔名自動歸入對應分類資料夾",
+  "autoCategorizeByExtensionDescription": "儲存至預設下載目錄時，根據檔案副檔名自動歸入對應分類資料夾。",
   "categoryExtensions": "檔案副檔名",
   "categoryExtensionsUsageHint": "支援逗號/空白分隔後綴，按回車新增。",
   "categoryExtensionsEmptyHint": "未設定後綴，檔案不會自動歸入此分類。",

ui/flutter/test/features/settings/application/settings_controller_test.dart

@@ -99,43 +99,6 @@ void main() {
     expect(saved.saving, isFalse);
   });
 
-  for (final field in ['port', 'DHT', 'PEX']) {
-    test('$field restart notice follows successful persisted changes only', () async {
-      var backend = DownloaderConfig();
-      var failNextSave = false;
-      final registry = CapabilityRegistry(createAppCapabilityCodecs())
-        ..bind(GopeedMethods.getConfig, (_) => DownloaderConfig.fromJson(backend.toJson()))
-        ..bind(GopeedMethods.putConfig, (config) {
-          if (failNextSave) {
-            failNextSave = false;
-            throw StateError('offline');
-          }
-          backend = DownloaderConfig.fromJson(config.toJson());
-          return const RpcUnit();
-        });
-      final container = _settingsContainer(registry);
-      addTearDown(container.dispose);
-      final initial = await container.read(settingsControllerProvider.future);
-      final controller = container.read(settingsControllerProvider.notifier);
-      final draft = DownloaderConfig.fromJson(initial.config.toJson());
-      switch (field) {
-        case 'port':
-          draft.protocolConfig.bt.listenPort = 6881;
-        case 'DHT':
-          draft.protocolConfig.bt.disableDht = true;
-        case 'PEX':
-          draft.protocolConfig.bt.disablePex = true;
-      }
-      failNextSave = true;
-      await expectLater(controller.save(draft), throwsStateError);
-      expect((await controller.save(draft)).btRestartRequired, isTrue);
-      expect((await controller.save(draft)).btRestartRequired, isFalse);
-      draft.protocolConfig.bt.seedRatio = 2;
-      expect((await controller.save(draft)).btRestartRequired, isFalse);
-      expect((await controller.save(initial.config)).btRestartRequired, isTrue);
-    });
-  }
-
   test('rapid full config saves run in order and keep the latest user edits', () async {
     final backend = DownloaderConfig();
     final entered = Completer<void>();
@@ -164,8 +127,7 @@ void main() {
     final savingSecond = controller.save(second);
     expect(puts.length, 1);
     release.complete();
-    final results = await Future.wait([savingFirst, savingSecond]);
+    await Future.wait([savingFirst, savingSecond]);
-    expect(results.map((result) => result.btRestartRequired), [true, false]);
     expect(puts, hasLength(2));
     expect(puts[0].protocolConfig.bt.listenPort, 6881);
     expect(puts[1].protocolConfig.bt.listenPort, 6881);

ui/flutter/test/features/tasks/presentation/create_task_advanced_toggle_test.dart

@@ -1,59 +0,0 @@
-import 'package:flutter/services.dart';
-import 'package:flutter/widgets.dart';
-import 'package:flutter_test/flutter_test.dart';
-import 'package:gopeed/features/tasks/presentation/widgets/create_task_advanced_toggle.dart';
-import 'package:gopeed/shared/theme/app_component_themes.dart';
-import 'package:gopeed/shared/theme/app_theme.dart';
-import 'package:shadcn_flutter/shadcn_flutter.dart' as shad;
-
-void main() {
-  for (final width in [360.0, 768.0, 1024.0]) {
-    testWidgets('advanced disclosure supports keyboard and touch at width $width', (tester) async {
-      tester.view.physicalSize = Size(width, 768);
-      tester.view.devicePixelRatio = 1;
-      addTearDown(tester.view.resetPhysicalSize);
-      addTearDown(tester.view.resetDevicePixelRatio);
-      var expanded = false;
-      await tester.pumpWidget(
-        shad.ShadcnApp(
-          theme: AppTheme.light(),
-          materialTheme: AppTheme.materialLight(),
-          home: AppComponentThemes(
-            child: StatefulBuilder(
-              builder: (context, setState) => Center(
-                child: Padding(
-                  padding: const EdgeInsets.all(16),
-                  child: CreateTaskAdvancedToggle(
-                    expanded: expanded,
-                    onPressed: () => setState(() => expanded = !expanded),
-                  ),
-                ),
-              ),
-            ),
-          ),
-        ),
-      );
-      await tester.pumpAndSettle();
-      expect(tester.getSize(find.byType(shad.GhostButton)).height, greaterThanOrEqualTo(44));
-      expect(
-        find.byWidgetPredicate((widget) => widget is Semantics && widget.properties.expanded == false),
-        findsOneWidget,
-      );
-      await tester.sendKeyEvent(LogicalKeyboardKey.tab);
-      await tester.pump();
-      await tester.sendKeyEvent(LogicalKeyboardKey.enter);
-      await tester.pumpAndSettle();
-      expect(expanded, isTrue);
-      expect(
-        find.byWidgetPredicate((widget) => widget is Semantics && widget.properties.expanded == true),
-        findsOneWidget,
-      );
-      await tester.tap(find.text('Advanced'));
-      await tester.pumpAndSettle();
-      expect(expanded, isFalse);
-      expect(tester.takeException(), isNull);
-      await tester.pumpWidget(const SizedBox.shrink());
-      await tester.pumpAndSettle();
-    });
-  }
-}

ui/flutter/test/widget_test.dart

@@ -1636,46 +1636,6 @@ void main() {
     expect(tester.takeException(), isNull);
   });
 
-  testWidgets('BT settings show a restart message only after an affected auto-save', (tester) async {
-    await _setTestSize(tester, const Size(1024, 900));
-    final controller = FakeSettingsController()..btRestartRequired = true;
-    await tester.pumpWidget(
-      ProviderScope(
-        overrides: [
-          appRuntimeControllerProvider.overrideWith(FakeRuntimeController.new),
-          appPlatformControllerProvider.overrideWith(FakePlatformController.new),
-          settingsControllerProvider.overrideWith(() => controller),
-        ],
-        child: const _SettingsTestApp(),
-      ),
-    );
-    await tester.pumpAndSettle();
-    await tester.tap(find.text('Downloads'));
-    await tester.pumpAndSettle();
-    const message = 'This setting takes effect after restarting the app';
-    expect(find.text(message), findsNothing);
-    final port = find.byKey(const ValueKey('bt-listen-port-input'));
-    await tester.ensureVisible(port);
-    await tester.pumpAndSettle();
-    await tester.enterText(port, '6881');
-    await tester.pump(const Duration(milliseconds: 500));
-    expect(find.text(message), findsNothing);
-    await tester.pump(const Duration(milliseconds: 200));
-    await tester.pump(const Duration(milliseconds: 300));
-    expect(find.text(message), findsOneWidget);
-    expect(tester.widget<AppToastContent>(find.byType(AppToastContent)).type, AppToastType.info);
-    await tester.pump(const Duration(seconds: 6));
-    await tester.pumpAndSettle();
-    controller.btRestartRequired = false;
-    final seedRatio = find.byKey(const ValueKey('bt-seed-ratio-input'));
-    await tester.ensureVisible(seedRatio);
-    await tester.enterText(seedRatio, '2');
-    await tester.pump(const Duration(milliseconds: 700));
-    await tester.pumpAndSettle();
-    expect(find.text(message), findsNothing);
-    expect(tester.takeException(), isNull);
-  });
-
   testWidgets('settings FTP connections save into the FTP protocol config', (WidgetTester tester) async {
     await _setTestSize(tester, const Size(1024, 900));
     final settingsController = FakeSettingsController();
@@ -6221,15 +6181,12 @@ ApiServerState _testApiServerState({
 }
 
 class FakeSettingsController extends SettingsController {
-  bool btRestartRequired = false;
-
   @override
   Future<SettingsState> build() async => SettingsState(config: DownloaderConfig());
 
   @override
-  Future<SettingsSaveResult> save(DownloaderConfig config) async {
+  Future<void> save(DownloaderConfig config) async {
     state = AsyncValue.data(SettingsState(config: config));
-    return SettingsSaveResult(btRestartRequired: btRestartRequired);
   }
 }
 

ui/flutter/windows/runner/CMakeLists.txt

@@ -7,6 +7,7 @@ project(runner LANGUAGES CXX)
 #
 # Any new source files that you add to the application should be added here.
 add_executable(${BINARY_NAME} WIN32
+  "crash_handler.cpp"
   "flutter_window.cpp"
   "main.cpp"
   "utils.cpp"
@@ -34,6 +35,7 @@ target_compile_definitions(${BINARY_NAME} PRIVATE "NOMINMAX")
 # dependencies here.
 target_link_libraries(${BINARY_NAME} PRIVATE flutter flutter_wrapper_app)
 target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
+target_link_libraries(${BINARY_NAME} PRIVATE "dbghelp.lib")
 target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")
 
 # Run the Flutter tool portions of the build. This must not be removed.

ui/flutter/windows/runner/CRASH_DIAGNOSTICS.md

@@ -0,0 +1,31 @@
+# Windows native crash diagnostics
+
+The runner installs diagnostics before starting Flutter and plugins. Files are
+written beside the executable under `storage/logs`, matching Windows app storage:
+
+- `native-crash.log`: UTC timestamp, app version, process/thread, exception code,
+  faulting module/address/offset, and minidump success or the Windows error code.
+- `native-crash.dmp`: the most recent native crash, including thread stacks,
+  loaded modules and unloaded module information.
+- `crash.log`: Go runtime crash output, kept separately from native diagnostics.
+
+Logs are appended and existing dumps survive normal restarts. A subsequent native
+crash replaces the previous dump. Dump generation is best effort, particularly
+for stack exhaustion, heap corruption or unavailable disk space. Process kills
+and fail-fast termination can bypass exception handlers.
+
+The top-level unhandled filter covers native exceptions on process threads. An
+SEH boundary inside the runner's window callback records the original escaping exception
+before Windows wraps a window callback failure as `0xC000041D`. A vectored handler
+also observes that fatal callback status, since it can bypass the unhandled
+filter. All handlers continue exception processing; they do not attempt recovery
+or log ordinary handled first-chance exceptions.
+
+On Windows, verify a release build by exercising tray clicks, Explorer restart,
+system font changes and child-window open/close. In a disposable test build,
+raise an unhandled access violation inside a window callback and on a worker
+thread, then raise `0xC000041D`; check that the log and dump are written and
+survive relaunch. A debugger may intercept these before application handlers.
+Open the dump with WinDbg and matching runner/Flutter/plugin PDBs to locate the
+faulting stack. Minidumps can contain application data; inspect them before
+sharing.

ui/flutter/windows/runner/crash_handler.cpp

@@ -0,0 +1,119 @@
+#include "crash_handler.h"
+
+#include <dbghelp.h>
+#include <strsafe.h>
+
+#include <cstdint>
+#include <cstring>
+#include <filesystem>
+#include <string>
+#include <system_error>
+
+namespace {
+
+HANDLE crash_log = INVALID_HANDLE_VALUE;
+std::wstring dump_path;
+volatile LONG recording = 0;
+LPTOP_LEVEL_EXCEPTION_FILTER previous_filter = nullptr;
+
+void WriteLog(const char* text) {
+  if (crash_log == INVALID_HANDLE_VALUE) return;
+  DWORD written = 0;
+  WriteFile(crash_log, text, static_cast<DWORD>(strlen(text)), &written,
+            nullptr);
+  FlushFileBuffers(crash_log);
+}
+
+LONG WINAPI UnhandledException(EXCEPTION_POINTERS* exception) {
+  RecordNativeCrash(exception);
+  return previous_filter ? previous_filter(exception)
+                         : EXCEPTION_CONTINUE_SEARCH;
+}
+
+LONG CALLBACK FatalCallbackException(EXCEPTION_POINTERS* exception) {
+  // Windows can terminate on this callback exception without invoking the
+  // process's unhandled filter. Ignore ordinary first-chance exceptions (Go,
+  // Dart and plugins may handle those) and observe only this fatal status.
+  if (exception->ExceptionRecord->ExceptionCode == 0xC000041D) {
+    RecordNativeCrash(exception);
+  }
+  return EXCEPTION_CONTINUE_SEARCH;
+}
+
+}  // namespace
+
+LONG RecordNativeCrash(EXCEPTION_POINTERS* exception) {
+  if (!exception || InterlockedCompareExchange(&recording, 1, 0) != 0) {
+    return EXCEPTION_CONTINUE_SEARCH;
+  }
+
+  SYSTEMTIME time;
+  GetSystemTime(&time);
+  const auto* record = exception->ExceptionRecord;
+  HMODULE module = nullptr;
+  wchar_t module_path[MAX_PATH] = L"unknown";
+  GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
+                        GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
+                    reinterpret_cast<LPCWSTR>(record->ExceptionAddress),
+                    &module);
+  if (module) GetModuleFileNameW(module, module_path, MAX_PATH);
+
+  char line[2048] = {};
+  StringCchPrintfA(
+      line, ARRAYSIZE(line),
+      "\r\n%04u-%02u-%02uT%02u:%02u:%02uZ Gopeed %s pid=%lu tid=%lu "
+      "exception=0x%08lX address=%p module=%ls offset=0x%llX\r\n",
+      time.wYear, time.wMonth, time.wDay, time.wHour, time.wMinute,
+      time.wSecond, FLUTTER_VERSION, GetCurrentProcessId(), GetCurrentThreadId(),
+      record->ExceptionCode, record->ExceptionAddress, module_path,
+      static_cast<unsigned long long>(
+          reinterpret_cast<uintptr_t>(record->ExceptionAddress) -
+          reinterpret_cast<uintptr_t>(module)));
+  WriteLog(line);
+
+  HANDLE dump = CreateFileW(dump_path.c_str(), GENERIC_WRITE, 0, nullptr,
+                            CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr);
+  if (dump != INVALID_HANDLE_VALUE) {
+    MINIDUMP_EXCEPTION_INFORMATION info = {};
+    info.ThreadId = GetCurrentThreadId();
+    info.ExceptionPointers = exception;
+    info.ClientPointers = FALSE;
+    const BOOL ok = MiniDumpWriteDump(
+        GetCurrentProcess(), GetCurrentProcessId(), dump,
+        static_cast<MINIDUMP_TYPE>(MiniDumpNormal | MiniDumpWithThreadInfo |
+                                   MiniDumpWithUnloadedModules),
+        &info, nullptr, nullptr);
+    const DWORD error = ok ? ERROR_SUCCESS : GetLastError();
+    FlushFileBuffers(dump);
+    CloseHandle(dump);
+    StringCchPrintfA(line, ARRAYSIZE(line), "minidump success=%d error=%lu\r\n",
+                     ok, error);
+    WriteLog(line);
+  } else {
+    StringCchPrintfA(line, ARRAYSIZE(line), "minidump open error=%lu\r\n",
+                     GetLastError());
+    WriteLog(line);
+  }
+
+  // Do not swallow an exception or resume a potentially corrupted process.
+  return EXCEPTION_CONTINUE_SEARCH;
+}
+
+void InstallCrashHandler() {
+  // Match Dart's Windows storage path independently of the working directory.
+  wchar_t executable[32768] = {};
+  const DWORD length = GetModuleFileNameW(nullptr, executable, ARRAYSIZE(executable));
+  if (length == 0 || length >= ARRAYSIZE(executable)) return;
+  const auto directory = std::filesystem::path(executable).parent_path() /
+                         L"storage" / L"logs";
+  std::error_code error;
+  std::filesystem::create_directories(directory, error);
+  if (error) return;
+
+  dump_path = (directory / L"native-crash.dmp").wstring();
+  crash_log = CreateFileW((directory / L"native-crash.log").c_str(),
+                         FILE_APPEND_DATA, FILE_SHARE_READ, nullptr, OPEN_ALWAYS,
+                         FILE_ATTRIBUTE_NORMAL, nullptr);
+  previous_filter = SetUnhandledExceptionFilter(UnhandledException);
+  AddVectoredExceptionHandler(1, FatalCallbackException);
+}

ui/flutter/windows/runner/crash_handler.h

@@ -0,0 +1,12 @@
+#ifndef RUNNER_CRASH_HANDLER_H_
+#define RUNNER_CRASH_HANDLER_H_
+
+#include <windows.h>
+
+// Installs best-effort native diagnostics before Flutter or plugins start.
+void InstallCrashHandler();
+
+// Records the exception and continues normal Windows exception processing.
+LONG RecordNativeCrash(EXCEPTION_POINTERS* exception);
+
+#endif  // RUNNER_CRASH_HANDLER_H_

ui/flutter/windows/runner/flutter_window.cpp

@@ -63,7 +63,9 @@ FlutterWindow::MessageHandler(HWND hwnd, UINT const message,
 
   switch (message) {
     case WM_FONTCHANGE:
+      if (flutter_controller_ && flutter_controller_->engine()) {
         flutter_controller_->engine()->ReloadSystemFonts();
+      }
       break;
   }
 

ui/flutter/windows/runner/main.cpp

@@ -5,6 +5,7 @@
 #include <desktop_multi_window/desktop_multi_window_plugin.h>
 
 #include "app_links/app_links_plugin_c_api.h"
+#include "crash_handler.h"
 #include "flutter_window.h"
 #include "flutter/generated_plugin_registrant.h"
 #include "utils.h"
@@ -43,6 +44,7 @@ bool IsMultiWindowLaunch(const std::vector<std::string>& arguments) {
 
 int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
                       _In_ wchar_t *command_line, _In_ int show_command) {
+  InstallCrashHandler();
   // Attach to console when present (e.g., 'flutter run') or create a
   // new console when running with a debugger.
   if (!::AttachConsole(ATTACH_PARENT_PROCESS) && ::IsDebuggerPresent()) {
@@ -77,11 +79,12 @@ int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
   window.SetQuitOnClose(true);
 
   ::MSG msg;
-  while (::GetMessage(&msg, nullptr, 0, 0)) {
+  BOOL message_result;
+  while ((message_result = ::GetMessage(&msg, nullptr, 0, 0)) > 0) {
     ::TranslateMessage(&msg);
     ::DispatchMessage(&msg);
   }
 
   ::CoUninitialize();
-  return EXIT_SUCCESS;
+  return message_result == -1 ? EXIT_FAILURE : static_cast<int>(msg.wParam);
 }

ui/flutter/windows/runner/win32_window.cpp

@@ -3,6 +3,7 @@
 #include <dwmapi.h>
 #include <flutter_windows.h>
 
+#include "crash_handler.h"
 #include "resource.h"
 
 namespace {
@@ -158,6 +159,9 @@ LRESULT CALLBACK Win32Window::WndProc(HWND const window,
                                       UINT const message,
                                       WPARAM const wparam,
                                       LPARAM const lparam) noexcept {
+  // Capture inside the callback, before user32 wraps or suppresses an escaping
+  // exception. Keep C++ objects requiring unwinding out of this SEH boundary.
+  __try {
     if (message == WM_NCCREATE) {
       auto window_struct = reinterpret_cast<CREATESTRUCT*>(lparam);
       SetWindowLongPtr(window, GWLP_USERDATA,
@@ -171,6 +175,10 @@ LRESULT CALLBACK Win32Window::WndProc(HWND const window,
     }
 
     return DefWindowProc(window, message, wparam, lparam);
+  } __except (RecordNativeCrash(GetExceptionInformation())) {
+    // The filter always continues the exception search; this is unreachable.
+    return 0;
+  }
 }
 
 LRESULT