existential-birds/beagle/bubbletea-code-review

BubbleTea Code Review

Hard gates (sequence)

Advance only when each pass condition is objectively true (reduces false positives on tea.Cmd and unsubstantiated blocking claims):

Quick Reference

CRITICAL: Avoid False Positives

Read [elm-architecture.md](references/elm-architecture.md) first! The most common review mistake is flagging correct patterns as bugs.

NOT Issues (Do NOT Flag These)

ACTUAL Issues (DO Flag These)

Review Checklist

Architecture

• [ ] No blocking I/O in Update() (file, network, sleep)
• [ ] Helper functions returning tea.Cmd are NOT flagged as blocking
• [ ] Commands used for all async operations

Model & Update

• [ ] Model is immutable (Update returns new model, not mutates)
• [ ] Init returns proper initial command (or nil)
• [ ] Update handles all expected message types
• [ ] WindowSizeMsg handled for responsive layout
• [ ] tea.Batch used for multiple commands
• [ ] tea.Quit used correctly for exit

View & Styling

• [ ] View is a pure function (no side effects)
• [ ] Lipgloss styles defined once, not in View
• [ ] Key bindings use key.Matches with help.KeyMap

Components

• [ ] Sub-component updates propagated correctly
• [ ] Bubbles components initialized with dimensions
• [ ] Huh forms embedded via Update loop (not Run())

Critical Patterns

Model Must Be Immutable

// BAD - mutates model
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
    m.items = append(m.items, newItem)  // mutation!
    return m, nil
}
 
// GOOD - returns new model
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
    newItems := make([]Item, len(m.items)+1)
    copy(newItems, m.items)
    newItems[len(m.items)] = newItem
    m.items = newItems
    return m, nil
}

Commands for Async/IO

// BAD - blocking in Update
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
    data, _ := os.ReadFile("config.json")  // blocks UI!
    m.config = parse(data)
    return m, nil
}
 
// GOOD - use commands
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
    return m, loadConfigCmd()
}
 
func loadConfigCmd() tea.Cmd {
    return func() tea.Msg {
        data, err := os.ReadFile("config.json")
        if err != nil {
            return errMsg{err}
        }
        return configLoadedMsg{parse(data)}
    }
}

Styles Defined Once

// BAD - creates new style each render
func (m Model) View() string {
    style := lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("205"))
    return style.Render("Hello")
}
 
// GOOD - define styles at package level or in model
var titleStyle = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("205"))
 
func (m Model) View() string {
    return titleStyle.Render("Hello")
}

When to Load References

• First time reviewing BubbleTea → elm-architecture.md (prevents false positives)
• Reviewing Update function logic → model-update.md
• Reviewing View function, styling → view-styling.md
• Reviewing component hierarchy → composition.md
• Using Bubbles components → bubbles-components.md

Review Questions

1. Is Update() free of blocking I/O? (NOT: "is the cmd helper blocking?")
2. Is the model immutable in Update?
3. Are Lipgloss styles defined once, not in View?
4. Is WindowSizeMsg handled for resizing?
5. Are key bindings documented with help.KeyMap?
6. Are Bubbles components sized correctly?