fix: long threads out of bounds

difflet_test.go

@@ -72,6 +72,52 @@ func TestDiffletStylesOnlyDiffSigns(t *testing.T) {
 	}
 }
 
+func TestDiffletAnimationDoesNotChangeThreadCommentRows(t *testing.T) {
+	if err := applyTheme("dark"); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = applyTheme("dark") })
+
+	app := NewAppWithSettings(
+		&recordingService{}, "owner", "repository", false, 10, 10,
+		AppSettings{Mascot: true, MascotAnimated: true},
+	)
+	app.screen = threadScreen
+	app.loading = false
+	app.details = PRDetails{
+		PullRequest: PullRequest{
+			Owner: "owner", Repository: "repository",
+			RepoWithOwner: "owner/repository", Number: 42,
+			Title: "Stable highlighted comments",
+		},
+		Threads: []ReviewThread{{
+			ID: "thread", Path: "main.go",
+			Comments: []ReviewComment{{
+				ID: "comment", Author: "reviewer",
+				Body: "```go\nfunc main() {\n\tprintln(\"stable\")\n}\n```",
+			}},
+		}},
+	}
+	updated, _ := app.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	app = updated.(App)
+	before := strings.Split(app.View(), "\n")
+
+	generation := app.difflet.generation
+	updated, _ = app.Update(diffletTickMsg{generation: generation})
+	app = updated.(App)
+	after := strings.Split(app.View(), "\n")
+
+	if len(before) != len(after) {
+		t.Fatalf("animation changed frame height from %d to %d", len(before), len(after))
+	}
+	for row := diffletHeight; row < len(before); row++ {
+		if before[row] != after[row] {
+			t.Fatalf("animation changed non-mascot row %d:\nbefore %q\nafter  %q",
+				row, before[row], after[row])
+		}
+	}
+}
+
 func TestDiffletEnabledSitsRightOfWrappingHeader(t *testing.T) {
 	app := NewAppWithSettings(
 		&recordingService{}, "owner", "repository", false, 10, 10,

markdown.go

@@ -97,6 +97,7 @@ func commentMarkdownRenderer(width int) (*glamour.TermRenderer, error) {
 	style.Code.Suffix = ""
 	renderer, err := glamour.NewTermRenderer(
 		glamour.WithStyles(style),
+		glamour.WithChromaFormatter("terminal16m"),
 		glamour.WithWordWrap(width),
 		glamour.WithTableWrap(true),
 		glamour.WithPreservedNewLines(),

terminal_cursor.go

@@ -49,6 +49,21 @@ func (o *terminalCursorOutput) Write(value []byte) (int, error) {
 	o.mu.Lock()
 	defer o.mu.Unlock()
 
+	// Bubble Tea v1 can expose intermediate rows from an animated partial
+	// repaint. This is especially visible when unchanged Markdown code blocks
+	// below the changed rows contain dense ANSI styling. Terminals that support
+	// synchronized output hold the completed frame until the reset sequence;
+	// terminals that do not support it safely ignore both sequences.
+	if !bytes.Equal(value, []byte(ansi.ShowCursor)) &&
+		!bytes.Equal(value, []byte(ansi.HideCursor)) {
+		if _, err := io.WriteString(o.file, ansi.SetSynchronizedOutputMode); err != nil {
+			return 0, err
+		}
+		defer func() {
+			_, _ = io.WriteString(o.file, ansi.ResetSynchronizedOutputMode)
+		}()
+	}
+
 	written, err := o.file.Write(value)
 	if err != nil || written != len(value) {
 		return written, err

terminal_cursor_test.go

@@ -25,7 +25,7 @@ func TestTerminalCursorOutputPositionsHardwareBarAfterFrame(t *testing.T) {
 		t.Fatal(err)
 	}
 	wantSuffix := ansi.SetCursorStyle(5) + ansi.CursorPosition(7, 4) + ansi.ShowCursor
-	if !strings.HasSuffix(string(content), wantSuffix) {
+	if !strings.HasSuffix(string(content), wantSuffix+ansi.ResetSynchronizedOutputMode) {
 		t.Fatalf("cursor output = %q, want suffix %q", content, wantSuffix)
 	}
 }
@@ -46,7 +46,33 @@ func TestTerminalCursorOutputHidesCursorOutsideInsertMode(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if !strings.HasSuffix(string(content), ansi.HideCursor) {
+	if !strings.HasSuffix(
+		string(content),
+		ansi.HideCursor+ansi.ResetSynchronizedOutputMode,
+	) {
 		t.Fatalf("cursor output did not hide cursor: %q", content)
 	}
 }
+
+func TestTerminalCursorOutputSynchronizesCompletedFrames(t *testing.T) {
+	file, err := os.CreateTemp(t.TempDir(), "cursor-output")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file.Close()
+
+	output := newTerminalCursorOutput(file)
+	output.SetCursor(false, 0, 0)
+	if _, err := output.Write([]byte("animated frame")); err != nil {
+		t.Fatal(err)
+	}
+	content, err := os.ReadFile(file.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := ansi.SetSynchronizedOutputMode + "animated frame" +
+		ansi.HideCursor + ansi.ResetSynchronizedOutputMode
+	if string(content) != want {
+		t.Fatalf("synchronized frame output = %q, want %q", content, want)
+	}
+}

tui.go

@@ -1906,6 +1906,12 @@ func (m App) dashboardMaxScroll() int {
 }
 
 func (m App) detailPaneSize() (int, int) {
+	if m.contentTop == 0 &&
+		len(m.difflet.frameLines()) == diffletHeight &&
+		!m.diffletHiddenForCurrentView() &&
+		m.screen != dashboardScreen {
+		m, _ = m.diffletContentModel()
+	}
 	topLines := m.threadTopLineCount()
 	height := max(3, m.height-topLines-1)
 	if m.width < 70 || m.listHidden {
@@ -1958,20 +1964,39 @@ func (m App) View() string {
 	if m.screen == dashboardScreen {
 		return m.viewDashboardWithLines(m.dashboardLinesWithDifflet(mascot))
 	}
-	gap := diffletGap
+	content, hasHeader := m.diffletContentModel()
+	if !hasHeader {
+		return lipgloss.NewStyle().Width(m.width).Height(m.height).Render(
+			strings.Join(mascot, "\n") + "\n\n" + content.viewContent(),
+		)
+	}
+	rendered := content.viewContent()
+	header, body, ok := splitHeader(rendered)
+	if !ok {
+		return lipgloss.NewStyle().Width(m.width).Height(m.height).Render(
+			strings.Join(mascot, "\n") + "\n\n" + rendered,
+		)
+	}
+	headerBand := renderHeaderWithDifflet(
+		header, mascot, m.width, content.headerWidth, diffletGap,
+	)
+	return lipgloss.NewStyle().Width(m.width).Height(m.height).Render(
+		headerBand + "\n\n" + body,
+	)
+}
+
+func (m App) diffletContentModel() (content App, hasHeader bool) {
 	headerWidth := diffletHeaderWidth(m.width)
 	if headerWidth < 1 {
 		headerWidth = m.width
 	}
-	content := m
+	content = m
 	content.headerWidth = headerWidth
 	headerLineCount, hasHeader := content.diffletHeaderLineCount()
 	if !hasHeader {
 		content.height = max(1, m.height-diffletHeight-1)
 		content.contentTop = diffletHeight + 1
-		return lipgloss.NewStyle().Width(m.width).Height(m.height).Render(
-			strings.Join(mascot, "\n") + "\n\n" + content.viewContent(),
-		)
+		return content, hasHeader
 	}
 	bandHeight := max(diffletHeight, headerLineCount)
 	addedRows := bandHeight - headerLineCount
@@ -1980,17 +2005,7 @@ func (m App) View() string {
 	}
 	content.height = max(1, m.height-addedRows)
 	content.contentTop = addedRows
-	rendered := content.viewContent()
-	header, body, ok := splitHeader(rendered)
-	if !ok {
-		return lipgloss.NewStyle().Width(m.width).Height(m.height).Render(
-			strings.Join(mascot, "\n") + "\n\n" + rendered,
-		)
-	}
-	headerBand := renderHeaderWithDifflet(header, mascot, m.width, headerWidth, gap)
-	return lipgloss.NewStyle().Width(m.width).Height(m.height).Render(
-		headerBand + "\n\n" + body,
-	)
+	return content, hasHeader
 }
 
 func (m App) diffletHiddenForCurrentView() bool {

tui_test.go

@@ -1189,35 +1189,82 @@ func TestReplyComposerRendersInlineWithCurrentThread(t *testing.T) {
 }
 
 func TestLongThreadCommentRemainsReachableByScrolling(t *testing.T) {
-	m := NewApp(nil, "o", "r", false, 50, time.Second)
-	m.screen, m.loading, m.width, m.height = threadScreen, false, 60, 12
+	for _, mascot := range []bool{false, true} {
+		t.Run(fmt.Sprintf("mascot=%t", mascot), func(t *testing.T) {
+			settings := defaultAppSettings()
+			settings.Mascot = mascot
+			m := NewAppWithSettings(
+				nil, "o", "r", false, 50, time.Second,
+				settings,
+			)
+			m.screen, m.loading = threadScreen, false
+			m.listHidden, m.focus = true, threadDetailPane
+			updated, _ := m.Update(tea.WindowSizeMsg{Width: 60, Height: 12})
+			m = updated.(App)
+			body := strings.Repeat("abcdefghij", 40) + "FINALMARKER"
+			m.details = PRDetails{
+				PullRequest: PullRequest{RepoWithOwner: "o/r", Number: 1, Title: "Title"},
+				Threads: []ReviewThread{{
+					ID: "thread", Path: "main.go", Line: 12,
+					Comments: []ReviewComment{{
+						ID: "comment", Author: "reviewer", Body: body,
+					}},
+				}},
+			}
+
+			width, _ := m.detailPaneSize()
+			lines := m.renderedDetailLines(width)
+			for _, line := range lines {
+				available := max(1, width-2-ansi.StringWidth(line.rail))
+				if got := ansi.StringWidth(line.fixed + line.text); got > available {
+					t.Fatalf("detail line width=%d available=%d text=%q",
+						got, available, ansi.Strip(line.text))
+				}
+			}
+			if m.detailMaxScroll() == 0 {
+				t.Fatal("long comment did not produce scrollable detail rows")
+			}
+			m.scroll = m.detailMaxScroll()
+			if view := ansi.Strip(m.View()); !strings.Contains(view, "FINALMARKER") {
+				t.Fatalf("final comment content is not reachable at maximum scroll:\n%s", view)
+			}
+		})
+	}
+}
+
+func TestLongThreadReplyComposerIsVisibleWithDifflet(t *testing.T) {
+	settings := defaultAppSettings()
+	settings.Mascot = true
+	m := NewAppWithSettings(
+		&recordingService{}, "o", "r", false, 50, time.Second,
+		settings,
+	)
+	m.screen, m.loading = threadScreen, false
 	m.listHidden, m.focus = true, threadDetailPane
-	body := strings.Repeat("abcdefghij", 40) + "FINALMARKER"
+	updated, _ := m.Update(tea.WindowSizeMsg{Width: 60, Height: 12})
+	m = updated.(App)
 	m.details = PRDetails{
-		PullRequest: PullRequest{RepoWithOwner: "o/r", Number: 1, Title: "Title"},
+		PullRequest: PullRequest{
+			ID: "pr", Owner: "o", Repository: "r",
+			RepoWithOwner: "o/r", Number: 1, Title: "Title",
+		},
 		Threads: []ReviewThread{{
-			ID: "thread", Path: "main.go", Line: 12,
+			ID: "thread", Path: "main.go", Line: 12, ViewerCanReply: true,
 			Comments: []ReviewComment{{
-				ID: "comment", Author: "reviewer", Body: body,
+				ID: "comment", Author: "reviewer",
+				Body: strings.Repeat("A long review comment. ", 40),
 			}},
 		}},
 	}
 
-	width, _ := m.detailPaneSize()
-	lines := m.renderedDetailLines(width)
-	for _, line := range lines {
-		available := max(1, width-2-ansi.StringWidth(line.rail))
-		if got := ansi.StringWidth(line.fixed + line.text); got > available {
-			t.Fatalf("detail line width=%d available=%d text=%q", got, available, ansi.Strip(line.text))
+	updated, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune("c")})
+	m = updated.(App)
+	view := ansi.Strip(m.View())
+	for _, wanted := range []string{"Reply draft", "ctrl+s review"} {
+		if !strings.Contains(view, wanted) {
+			t.Fatalf("long-thread reply view is missing %q:\n%s", wanted, view)
 		}
 	}
-	if m.detailMaxScroll() == 0 {
-		t.Fatal("long comment did not produce scrollable detail rows")
-	}
-	m.scroll = m.detailMaxScroll()
-	if view := ansi.Strip(m.viewThreads()); !strings.Contains(view, "FINALMARKER") {
-		t.Fatalf("final comment content is not reachable at maximum scroll:\n%s", view)
-	}
 }
 
 func TestResolveToggleConfirmsAndUsesCurrentThreadState(t *testing.T) {

version.go

@@ -1,3 +1,3 @@
 package main
 
-const dipleVersion = "0.1.1"
+const dipleVersion = "0.1.3"