change panicking functions in Client and EntityRef to return an AzaleaResult instead

1 files changed, 29 insertions, 0 deletions

diff --git a/azalea/src/client_impl/error.rs b/azalea/src/client_impl/error.rs
new file mode 100644
index 00000000..ce3ecab4
--- /dev/null
+++ b/azalea/src/client_impl/error.rs
@@ -0,0 +1,29 @@
+use bevy_ecs::entity::Entity;
+use thiserror::Error;
+
+/// An error that occurs when we tried to access data from an entity that it
+/// doesn't have.
+///
+/// This could happen because the data does not occur for this type of entity,
+/// or because the entity is not currently loaded.
+///
+/// If this error happened when trying to access data on a client, then it may
+/// be because the client isn't currently in a world.
+///
+/// As an alias for `Result<T, MissingComponentError>`, you may use
+/// [`AzaleaResult`]. Using the `eyre` or `anyhow` crates may also simplify
+/// error handling in your bots.
+#[derive(Error, Debug)]
+#[error("{entity_description} {entity} is missing a required component: '{component}'")]
+pub struct MissingComponentError {
+    /// Should be "Entity" or "Client"
+    pub entity_description: &'static str,
+    pub entity: Entity,
+    pub component: &'static str,
+}
+
+/// An error that occurs when we tried to access data from an entity that it
+/// doesn't have.
+///
+/// See [`MissingComponentError`] for more details.
+pub type AzaleaResult<T> = Result<T, MissingComponentError>;