Struct ExtKey 

pub struct ExtKey<T> { /* private fields */ }

Typed handle for extension component storage.

Constructed via ExtKey::new with an explicit name, or ExtKey::from_type_name which uses std::any::type_name::<T>().

Snapshot stability

The name is the wire-format key for snapshot extension storage. Prefer ExtKey::new with an explicit string for any production or persisted scenario — std::any::type_name::<T>() is documented as not guaranteed stable across compilations and can drift in practice (renamed crates, generic monomorphization choices, future compiler releases). A snapshot saved on one build profile and restored on another whose type_name<T>() differs will silently drop the extension data.

assert_ext_name_unique (called by register_ext and insert_ext) panics on in-process collisions, so in-memory drift is loud; the silent failure mode is purely a snapshot-restore-on-a different-build issue.

Implementations

impl<T> ExtKey<T>

pub const fn new(name: &'static str) -> Self

Create a key with an explicit storage name.

pub fn from_type_name() -> Self

Create a key using std::any::type_name::<T>() as the storage name.

Convenient for prototyping and tests, but the resulting name is not snapshot-stable across builds — see the type-level “Snapshot stability” note. Production code that persists snapshots should use ExtKey::new with an explicit name.

pub const fn name(&self) -> &'static str

The storage name for this key.

Trait Implementations

impl<T> Clone for ExtKey<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for ExtKey<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Default for ExtKey<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> Copy for ExtKey<T>