An exception that is raised when an application depends on one or more missing applications.

This exception is used by Mix and other tools. It can also be used by library authors when their library only requires an external application (like a dependency) for a subset of features.

The fields of this exception are public. See t/0.

Available since v1.18.0.

Examples

unless Application.spec(:plug, :vsn) do
  raise MissingApplicationsError,
    description: "application :plug is required for testing Plug-related functionality",
    apps: [{:plug, "~> 1.0"}]
end