Stop a table cursor from getting stuck at -1

Assigning an on-call week panicked with "index out of range [-1]" on an
ordinary schedule. The index came from scheduleTable.Cursor().

The cursor is not ours. bubbles' SetRows clamps it down when rows shrink
(`if m.cursor > len(rows)-1`) but never back up, so setting zero rows drives it
to -1 and filling the table afterwards leaves it there -- -1 is not greater
than len-1, so nothing corrects it. Every table in this package is rebuilt from
empty exactly once, when the first WindowSizeMsg arrives before any fetch has
returned, so every cursor started at -1 and stayed there until the user pressed
up or down. Pressing a direction key first is why this was survivable at all.

setRows restores the invariant the rest of the package already assumes: a table
with rows has a usable cursor. Every rebuild goes through it.

Five call sites also bounds-checked only the top of the range, and are now
consistent with their siblings, which already had `i < 0 ||`. They were the
same latent panic: deleting a schedule entry, deleting a user, editing a topic,
opening the API key menu, and the week assignment that actually fired.

The regression test deliberately never calls SetCursor. That is what the
existing schedule tests do, and SetCursor clamps, which is exactly how this got
past them. It drives the real order instead: size, then data, then keys.

Also carries a gofmt pass, which is why untouched files appear in the diff.
The move to git.ryuvia.com rewrote import paths without re-sorting them, and
the new path sorts before github.com/charmbracelet/..., where the old one
sorted after. go vet does not look at import order, so CI had nothing to say.

internal/tui/model.go

@@ -4,13 +4,13 @@ import (
 	"fmt"
 	"time"
 
+	"git.ryuvia.com/niklas/terdut-tui/internal/api"
 	"github.com/charmbracelet/bubbles/help"
 	"github.com/charmbracelet/bubbles/table"
 	"github.com/charmbracelet/bubbles/textinput"
 	"github.com/charmbracelet/bubbles/viewport"
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
-	"git.ryuvia.com/niklas/terdut-tui/internal/api"
 )
 
 // ── Enums ──────────────────────────────────────────────────────────────────
@@ -354,27 +354,45 @@ func defaultTableStyles() table.Styles {
 	return s
 }
 
+// setRows replaces a table's rows and keeps its cursor in a state the rest of
+// this package can rely on: valid whenever the table has any rows at all.
+//
+// bubbles does not do that on its own. SetRows only clamps the cursor *down*
+// (`if m.cursor > len(rows)-1`), so setting zero rows drives it to -1 and
+// nothing ever brings it back — filling the table later leaves -1 in place,
+// because -1 is not greater than len-1. Every table here is rebuilt from empty
+// once at startup, when the first WindowSizeMsg arrives before any fetch has
+// returned, so without this every cursor is -1 until the user happens to press
+// up or down. Indexing a slice with that panics, which is exactly what
+// assigning an on-call week did.
+func setRows(t *table.Model, rows []table.Row) {
+	t.SetRows(rows)
+	if len(rows) > 0 && t.Cursor() < 0 {
+		t.SetCursor(0)
+	}
+}
+
 func (m *Model) rebuildIncidentTable() {
 	m.incidentTable.SetColumns(incidentColumns(m.width))
-	m.incidentTable.SetRows(incidentRows(m.incidents))
+	setRows(&m.incidentTable, incidentRows(m.incidents))
 	m.incidentTable.SetHeight(tableHeight(m.height, 8))
 }
 
 func (m *Model) rebuildTable() {
 	m.alertTable.SetColumns(alertColumns(m.width))
-	m.alertTable.SetRows(alertRows(m.alerts))
+	setRows(&m.alertTable, alertRows(m.alerts))
 	m.alertTable.SetHeight(tableHeight(m.height, 8))
 }
 
 func (m *Model) rebuildArchivedTable() {
 	m.archivedTable.SetColumns(incidentColumns(m.width))
-	m.archivedTable.SetRows(incidentRows(m.archivedIncidents))
+	setRows(&m.archivedTable, incidentRows(m.archivedIncidents))
 	m.archivedTable.SetHeight(tableHeight(m.height, 8))
 }
 
 func (m *Model) rebuildScheduleTable() {
 	m.scheduleTable.SetColumns(scheduleColumns(m.width))
-	m.scheduleTable.SetRows(scheduleRows(m.scheduleDays))
+	setRows(&m.scheduleTable, scheduleRows(m.scheduleDays))
 	m.scheduleTable.SetHeight(tableHeight(m.height, 10))
 }
 
@@ -384,7 +402,7 @@ func (m *Model) rebuildUserPickerTable() {
 	for i, u := range m.users {
 		rows[i] = table.Row{u.Username, u.Email}
 	}
-	m.userPickerTable.SetRows(rows)
+	setRows(&m.userPickerTable, rows)
 	m.userPickerTable.SetHeight(tableHeight(m.height, 10))
 }
 
@@ -398,7 +416,7 @@ func (m *Model) rebuildUserManageTable() {
 		}
 		rows[i] = table.Row{u.Username, u.Email, topic, u.CreatedAt.UTC().Format("2006-01-02")}
 	}
-	m.userManageTable.SetRows(rows)
+	setRows(&m.userManageTable, rows)
 	m.userManageTable.SetHeight(tableHeight(m.height, 10))
 }
 

internal/tui/model_test.go

@@ -4,8 +4,8 @@ import (
 	"testing"
 	"time"
 
-	"github.com/charmbracelet/bubbles/table"
 	"git.ryuvia.com/niklas/terdut-tui/internal/api"
+	"github.com/charmbracelet/bubbles/table"
 )
 
 func TestNextFilter(t *testing.T) {

internal/tui/styles.go

@@ -3,8 +3,8 @@ package tui
 import (
 	"strings"
 
-	"github.com/charmbracelet/lipgloss"
 	"git.ryuvia.com/niklas/terdut-tui/internal/api"
+	"github.com/charmbracelet/lipgloss"
 )
 
 var (

internal/tui/update.go

@@ -4,10 +4,10 @@ import (
 	"strconv"
 	"strings"
 
+	"git.ryuvia.com/niklas/terdut-tui/internal/api"
 	"github.com/atotto/clipboard"
 	"github.com/charmbracelet/bubbles/viewport"
 	tea "github.com/charmbracelet/bubbletea"
-	"git.ryuvia.com/niklas/terdut-tui/internal/api"
 )
 
 func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
@@ -468,7 +468,7 @@ func (m Model) handleDashboardKey(msg tea.KeyMsg) (Model, tea.Cmd) {
 				return m, nil
 			}
 			cursor := m.scheduleTable.Cursor()
-			if cursor >= len(m.scheduleDays) {
+			if cursor < 0 || cursor >= len(m.scheduleDays) {
 				return m, nil
 			}
 			day := m.scheduleDays[cursor]
@@ -484,7 +484,7 @@ func (m Model) handleDashboardKey(msg tea.KeyMsg) (Model, tea.Cmd) {
 				return m, nil
 			}
 			cursor := m.userManageTable.Cursor()
-			if cursor >= len(m.users) {
+			if cursor < 0 || cursor >= len(m.users) {
 				return m, nil
 			}
 			m.selectedUser = m.users[cursor]
@@ -510,7 +510,7 @@ func (m Model) handleDashboardKey(msg tea.KeyMsg) (Model, tea.Cmd) {
 			return m, nil
 		}
 		cursor := m.userManageTable.Cursor()
-		if cursor >= len(m.users) {
+		if cursor < 0 || cursor >= len(m.users) {
 			return m, nil
 		}
 		m.selectedUser = m.users[cursor]
@@ -527,7 +527,7 @@ func (m Model) handleDashboardKey(msg tea.KeyMsg) (Model, tea.Cmd) {
 			return m, nil
 		}
 		cursor := m.userManageTable.Cursor()
-		if cursor >= len(m.users) {
+		if cursor < 0 || cursor >= len(m.users) {
 			return m, nil
 		}
 		m.selectedUser = m.users[cursor]
@@ -893,7 +893,7 @@ func (m Model) handleUserPickerKey(msg tea.KeyMsg) (Model, tea.Cmd) {
 		}
 
 		scheduleCursor := m.scheduleTable.Cursor()
-		if scheduleCursor >= len(m.scheduleDays) {
+		if scheduleCursor < 0 || scheduleCursor >= len(m.scheduleDays) {
 			m.mode = modeDashboard
 			return m, nil
 		}

internal/tui/update_test.go

@@ -5,8 +5,8 @@ import (
 	"testing"
 	"time"
 
-	tea "github.com/charmbracelet/bubbletea"
 	"git.ryuvia.com/niklas/terdut-tui/internal/api"
+	tea "github.com/charmbracelet/bubbletea"
 )
 
 // press sends one key and returns the resulting model and command. A nil command
@@ -676,3 +676,50 @@ func containsAll(s string, subs ...string) bool {
 	}
 	return true
 }
+
+// The bug: assigning an on-call week panicked with "index out of range [-1]"
+// on a perfectly normal schedule, as long as nobody had moved the cursor first.
+//
+// The cause is not in this package. bubbles' SetRows clamps the cursor down but
+// never up, so the empty rebuild every table gets from the first WindowSizeMsg
+// -- which arrives before any fetch returns -- pins the cursor at -1, and
+// loading real rows afterwards leaves it there. Pressing up or down hid it,
+// which is why every existing test missed it: they all call SetCursor, and
+// SetCursor clamps.
+//
+// So this test must NOT touch the cursor. It reproduces the real order of
+// events: size first, data second, keys third.
+func TestSchedule_AssignWeekAfterStartupSizingDoesNotPanic(t *testing.T) {
+	m := NewModel(nil, "http://test", time.Minute)
+	m.connected = true
+	m.activeSection = sectionSchedule
+	m.scheduleWindow = time.Date(2026, 7, 27, 0, 0, 0, 0, time.UTC)
+
+	// 1. Terminal size arrives while every table is still empty.
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 120, Height: 40})
+	m = next.(Model)
+
+	// 2. The schedule and the user list land.
+	next, _ = m.Update(scheduleFetchedMsg{entries: []api.ScheduleEntry{}})
+	m = next.(Model)
+	next, _ = m.Update(usersFetchedMsg{users: []api.User{
+		{ID: 1, Username: "niklas", Email: "n@example.com"},
+	}})
+	m = next.(Model)
+
+	if got := m.scheduleTable.Cursor(); got < 0 {
+		t.Fatalf("schedule cursor is %d after loading %d days; a populated table must have a usable cursor",
+			got, len(m.scheduleDays))
+	}
+
+	// 3. Assign the week to the first user, without ever moving a cursor.
+	m, _ = press(t, m, "W")
+	if m.mode != modeUserPicker {
+		t.Fatalf("W did not open the user picker, got mode %v", m.mode)
+	}
+	m, _ = press(t, m, "enter") // panicked here
+
+	if m.mode == modeUserPicker {
+		t.Fatal("enter left the picker open; the assignment never went anywhere")
+	}
+}

internal/tui/view.go

@@ -6,8 +6,8 @@ import (
 	"strings"
 	"time"
 
-	"github.com/charmbracelet/lipgloss"
 	"git.ryuvia.com/niklas/terdut-tui/internal/api"
+	"github.com/charmbracelet/lipgloss"
 )
 
 // Order must match the section constants — renderTabs indexes this by ordinal.

internal/tui/view_test.go

@@ -6,8 +6,8 @@ import (
 	"testing"
 	"time"
 
-	tea "github.com/charmbracelet/bubbletea"
 	"git.ryuvia.com/niklas/terdut-tui/internal/api"
+	tea "github.com/charmbracelet/bubbletea"
 )
 
 // ansi matches the escape sequences lipgloss emits when it decides the output

main.go

@@ -5,11 +5,11 @@ import (
 	"fmt"
 	"os"
 
-	tea "github.com/charmbracelet/bubbletea"
 	"git.ryuvia.com/niklas/terdut-tui/internal/api"
 	"git.ryuvia.com/niklas/terdut-tui/internal/config"
 	"git.ryuvia.com/niklas/terdut-tui/internal/tui"
 	"git.ryuvia.com/niklas/terdut-tui/internal/updater"
+	tea "github.com/charmbracelet/bubbletea"
 )
 
 var version = "dev"