Struct CheckContext 

pub struct CheckContext<'a> {
    pub backend: &'a dyn DatabaseBackend,
    pub settings: &'a Settings,
    pub provides_storage: bool,
    pub registered_plugin_names: &'a [&'a str],
}

Context available to a system check at boot.

Holds references to everything a check might consult: the active backend, the validated settings. The model list (M5) and plugin registry (M7) get added when they exist.

Fields

backend: &'a dyn DatabaseBackend

The active database backend.

settings: &'a Settings

The runtime settings, post-load, pre-publish.

provides_storage: bool

true when at least one registered plugin reports crate::plugin::Plugin::provides_storage. The field.storage_backend check reads this to decide whether a model with a FileField / ImageField has a backend to resolve uploads through.

This is the capability flag of the plugin list, not the ambient crate::storage::storage_opt() — storage is registered in on_ready, which runs after this check, so the ambient backend isn’t published yet at check time. App::build populates this from the sorted plugin list before running the checks. Tests that build a CheckContext by hand (without a plugin walk) set true to keep the storage check inert.

registered_plugin_names: &'a [&'a str]

The names of every registered plugin, in topological order, as returned by crate::plugin::Plugin::name. Populated by App::build before running phase 4 checks. Tests that build a CheckContext by hand should supply an empty slice (&[]) to make plugin-aware checks that need a specific set of names inert, or supply the names they want to exercise directly.