# Upgrading to v0.19

## Bump Your Deps

Update Backpex to the latest version:

```elixir
defp deps do
  [
    {:backpex, "~> 0.19.0"}
  ]
end
```

## `Backpex.LiveResource` now imports `Phoenix.Component` instead of using it

Previously, `use Backpex.LiveResource` brought in the full `use Phoenix.Component` (transitively, via `use BackpexWeb, :html`). It now only *imports* `Phoenix.Component`.

### Why this changed

`use Phoenix.Component` registers a `@before_compile` hook that Elixir does not deduplicate. If your LiveResource also brought in `Phoenix.Component` — for example through `use MyAppWeb, :html` (to get your app's components, gettext and verified routes) — that hook ran twice and generated its compile-time component verification code twice. Elixir 1.20+ rejects the resulting duplicate function clause as a redundant clause, failing compilation under `--warnings-as-errors`.

A LiveResource only needs the `~H` sigil (for the injected `render_resource_slot/3` clauses and for your own render functions), and `import Phoenix.Component` provides that without registering the hook. This resolves the compile failure.

### Do you need to change anything?

**No changes required in the common case.** LiveResources that only use the `~H` sigil — in `render_resource_slot/3` overrides or inline `render:` field closures — continue to work unchanged.

**Action required only if** you declare your own function components with `attr`/`slot` (or `embed_templates`, or the component-aware `def`) *directly inside a LiveResource module*. This previously worked because `Phoenix.Component` was pulled in via `use`. Now you must additionally bring it in yourself with `use MyAppWeb, :html` (or `use Phoenix.Component`):

**Before (worked in v0.18):**

```elixir
defmodule MyAppWeb.PostLive do
  use Backpex.LiveResource,
    adapter_config: [...]

  attr :label, :string, required: true

  def badge(assigns) do
    ~H"""
    <span class="badge">{@label}</span>
    """
  end
end
```

**After:**

```elixir
defmodule MyAppWeb.PostLive do
  use Backpex.LiveResource,
    adapter_config: [...]

  use MyAppWeb, :html # or `use Phoenix.Component`

  attr :label, :string, required: true

  def badge(assigns) do
    ~H"""
    <span class="badge">{@label}</span>
    """
  end
end
```