List Model Index returns index offset based on filtered list, but SetItem expects global offset in items list.

[blkt]

Describe the bug
The index value retrieved by using Index returns an offset that implicitly takes into account whether filtering is active, so an hypothetical value o 0 is actually the first item in the filtered list of items.

On the other hand, SetItem expects an index to be used with the global list of items, both filtered and unfiltered.

This makes it hard (if not impossible) to update an item within a filtered list.

I definitely might be using bubbletea list wrong, please let me know if that's the case.

Setup
Please complete the following information along with version numbers, if applicable.

• OS macOS
• Shell zsh
• Terminal Emulator iterm
• Terminal Multiplexer none
• Locale en_US.UTF-8

To Reproduce
Using code below:

1. using / filter by b
2. push space on the first item
3. remove filtering
4. item at position 0, i.e. a, was replaced instead of b

Source Code
Here is a minimal model usable to reproduce the issue, also found here.

package main

import (
	"cmp"
	"fmt"
	"io"
	"slices"
	"strings"

	"github.com/charmbracelet/bubbles/key"
	"github.com/charmbracelet/bubbles/list"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
)

func MultiSelect(choices []string) ([]string, error) {
	items := make([]list.Item, 0, len(choices))
	for _, c := range choices {
		items = append(items, item{title: c})
	}

	slices.SortFunc(items, func(a, b list.Item) int {
		return cmp.Compare(a.(item).title, b.(item).title)
	})

	l := list.New(items, itemDelegate{}, 0, 0)
	l.Title = "Select repos to register"
	l.AdditionalShortHelpKeys = extraKeys
	l.AdditionalFullHelpKeys = extraKeys

	height := 30 // 20 + 10, 10 is a magic number to show 20 items
	if size := len(items); size < 20 {
		height = size + 10
	}
	model := model{list: l, height: height}
	p := tea.NewProgram(model)
	if _, err := p.Run(); err != nil {
		return nil, err
	}

	selection := make([]string, 0, len(items))
	for _, listItem := range items {
		item := listItem.(item)
		if item.checked {
			selection = append(selection, item.title)
		}
	}

	return selection, nil
}

var (
	itemStyle         = lipgloss.NewStyle().PaddingLeft(4)
	selectedItemStyle = lipgloss.NewStyle().PaddingLeft(2)
)

type item struct {
	title   string
	checked bool
}

func (i item) Title() string       { return i.title }
func (_ item) Description() string { return "" }
func (i item) FilterValue() string { return i.title }

type itemDelegate struct{}

func (_ itemDelegate) Height() int                             { return 1 }
func (_ itemDelegate) Spacing() int                            { return 0 }
func (_ itemDelegate) Update(_ tea.Msg, _ *list.Model) tea.Cmd { return nil }
func (_ itemDelegate) Render(w io.Writer, m list.Model, index int, listItem list.Item) {
	i, ok := listItem.(item)
	if !ok {
		return
	}

	fn := itemStyle.Render
	if index == m.Index() {
		fn = func(s ...string) string {
			return selectedItemStyle.Render("> " + strings.Join(s, " "))
		}
	}

	checked := "[ ]"
	if i.checked {
		checked = "[x]"
	}

	fmt.Fprint(w, fn(checked, i.title))
}

type model struct {
	list   list.Model
	height int
}

func (_ model) Init() tea.Cmd {
	return nil
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.list.SetSize(0, m.height)

	case tea.KeyMsg:
		switch msg.String() {
		case "ctrl+c", "enter":
			return m, tea.Quit
		case " ":
			idx := m.list.Index()
			oldItem := m.list.SelectedItem().(item)
			cmd := m.list.SetItem(idx, item{
				title:   oldItem.title,
				checked: !oldItem.checked,
			})
			return m, cmd
		}
	}

	var cmd tea.Cmd
	m.list, cmd = m.list.Update(msg)
	return m, cmd
}

func (m model) View() string {
	return m.list.View()
}

func extraKeys() []key.Binding {
	return []key.Binding{
		key.NewBinding(
			key.WithKeys("space"),
			key.WithHelp("space", "select item"),
		),
	}
}

func main() {
	MultiSelect([]string{"a", "b1", "b2", "b3", "c"})
}

Expected behavior
The item under selection is modified and not an arbitrary one.

[nobe4]

👋 @blkt I have potentially found a solution for this, and implemented a fix in #574

[blkt]

That's great @nobe4, thank you for looking into this!