# `Localize.LocaleCacheDirError`
[🔗](https://github.com/elixir-localize/localize/blob/v0.41.0/lib/localize/exception/locale_cache_dir_error.ex#L1)

Exception raised when the `:locale_cache_dir` or `:otp_app`
application environment keys are misconfigured.

Three failure modes:

* `:relative_path` — `:locale_cache_dir` is a relative string **and**
  no `:otp_app` is configured to anchor it. A relative path with no
  anchor resolves against the BEAM's current working directory,
  which differs between `mix` tasks (CWD = project root), `mix test`,
  and a release (CWD = release root) — one value cannot be correct
  in all phases.

* `:invalid_form` — `:locale_cache_dir` is set but is not a string.

* `:invalid_otp_app` — `:otp_app` is set but is not an atom.

## Supported configurations

Three forms are accepted:

1. **`:otp_app` only** (recommended) — caches in
   `Application.app_dir(<otp_app>, "priv/localize/locales")`:

        config :localize, otp_app: :my_app

2. **`:otp_app` + relative `:locale_cache_dir`** — caches in
   `Application.app_dir(<otp_app>, <relative>)`:

        config :localize,
          otp_app: :my_app,
          locale_cache_dir: "priv/i18n/cache"

3. **Absolute `:locale_cache_dir`** — used verbatim; `:otp_app`
   is ignored:

        config :localize, locale_cache_dir: "/var/lib/localize/locales"

`:otp_app` follows the Elixir/Phoenix/Ecto/Gettext convention.
`Application.app_dir/2` is re-resolved at every read, so the same
config value produces the correct path in mix tasks
(`_build/<env>/lib/<app>/priv/...`) and in releases
(`/path/to/release/lib/<app>-X.Y.Z/priv/...`) without per-phase
duplication.

# `reason`

```elixir
@type reason() :: :relative_path | :invalid_form | :invalid_otp_app
```

# `t`

```elixir
@type t() :: %Localize.LocaleCacheDirError{
  __exception__: term(),
  detail: String.t() | nil,
  reason: reason() | nil,
  value: term() | nil
}
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*