UndefinedFunctionError when creating LiveView

Hello, I’m trying to create my first LiveView

I have

router.ex

scope "/", TestWeb do
  pipe_through :browser
  live "/app", AppLive
end

app_live.ex

defmodule TestWeb.AppLive do
  use TestWeb, :live_view
  
  def render(assigns) do
    ~H"""
    test
    """
  end

  def mount(_params, _session, _socket) do
  end
end

but I get

UndefinedFunctionError at GET /app

function TestWeb.AppLive.__live__/0 is undefined (module TestWeb.AppLive is not available)

Can you share a code ob TestWeb module please? It appears that the project was generated without live_view support

I don’t really have other TestWeb module other than the standards modules generate by phx.new (I used phx.new 1.7.6 so I think there is LiveView support by default ?)

I have this for example

defmodule TestWeb.AppController do
  use TestWeb, :controller
end

defmodule TestWeb.PageController do
  use TestWeb, :controller

  def home(conn, _params) do
    # The home page is often custom made,
    # so skip the default app layout.
    render(conn, :home, layout: false)
  end
end

No, you have TestWeb module. It should be located at lib/test_web.ex

Yes I have

defmodule TestWeb do
  @moduledoc """
  The entrypoint for defining your web interface, such
  as controllers, components, channels, and so on.

  This can be used in your application as:

      use TestWeb, :controller
      use TestWeb, :html

  The definitions below will be executed for every controller,
  component, etc, so keep them short and clean, focused
  on imports, uses and aliases.

  Do NOT define functions inside the quoted expressions
  below. Instead, define additional modules and import
  those modules here.
  """

  def static_paths, do: ~w(assets fonts images favicon.ico robots.txt)

  def router do
    quote do
      use Phoenix.Router, helpers: false

      # Import common connection and controller functions to use in pipelines
      import Plug.Conn
      import Phoenix.Controller
      import Phoenix.LiveView.Router
    end
  end

  def channel do
    quote do
      use Phoenix.Channel
    end
  end

  def controller do
    quote do
      use Phoenix.Controller,
        formats: [:html, :json],
        layouts: [html: TestWeb.Layouts]

      import Plug.Conn
      import TestWeb.Gettext

      unquote(verified_routes())
    end
  end

  def live_view do
    quote do
      use Phoenix.LiveView,
        layout: {TestWeb.Layouts, :app}

      unquote(html_helpers())
    end
  end

  def live_component do
    quote do
      use Phoenix.LiveComponent

      unquote(html_helpers())
    end
  end

  def html do
    quote do
      use Phoenix.Component

      # Import convenience functions from controllers
      import Phoenix.Controller,
        only: [get_csrf_token: 0, view_module: 1, view_template: 1]

      # Include general helpers for rendering HTML
      unquote(html_helpers())
    end
  end

  defp html_helpers do
    quote do
      # HTML escaping functionality
      import Phoenix.HTML
      # Core UI components and translation
      import TestWeb.CoreComponents
      import TestWeb.Gettext

      # Shortcut for generating JS commands
      alias Phoenix.LiveView.JS

      # Routes generation with the ~p sigil
      unquote(verified_routes())
    end
  end

  def verified_routes do
    quote do
      use Phoenix.VerifiedRoutes,
        endpoint: TestWeb.Endpoint,
        router: TestWeb.Router,
        statics: TestWeb.static_paths()
    end
  end

  @doc """
  When used, dispatch to the appropriate controller/view/etc.
  """
  defmacro __using__(which) when is_atom(which) do
    apply(__MODULE__, which, [])
  end
end

Where did you put module TestWeb.AppLive?

In test/lib/test_web/live/app_live.ex

Maybe I have the same error that this issue Live Components suddenly not compiling, app crashing with UndefinedFunctionError ?

[No working]

By creating a new app (without database) I have no longer this warning: Couldn't watch /home/computer/test: Too many open files (can be a link ?)
And it’s working

That’s definitely not a solution. What happens when you actually do add it?

Also you never followed up on your other thread about the too many open files – there is a solution but it seems you either did not pursue it, or have not updated the thread.

I came to this thread while searching for the following error in my test output.

MyAppWeb.Dashboard.OrderLive.__live__/0 is undefined or private

The issue for me was that I had named my test module incorrectly. I forgot to add Test at the end.

Updating the test module from MyAppWeb.Dashboard.OrderLive to MyAppWeb.Dashboard.OrderLiveTest fixed my issue.