steid

steid/src/domain/error.rs

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1e1ae56feat: identity domain model1mo	1	use std::fmt;
	2
	3	/// Every way a domain rule can be violated.
	4	///
	5	/// Deliberately coarse: a variant earns its place when a caller needs to react to it
	6	/// differently, not merely to describe a failure more precisely.
	7	#[derive(Debug, Clone, PartialEq, Eq)]
	8	pub enum DomainError {
	9	/// A value failed validation. Carries the field and the reason.
	10	Validation { field: String, reason: String },
	11	/// The requested entity does not exist.
	12	NotFound { entity: &'static str },
	13	/// The entity already exists and the operation requires it not to.
	14	AlreadyExists { entity: &'static str },
	15	/// Credentials did not match. Deliberately says nothing about which part failed.
	16	InvalidCredentials,
	17	}
	18
	19	impl DomainError {
	20	pub fn validation(field: impl Into<String>, reason: impl Into<String>) -> Self {
	21	Self::Validation {
	22	field: field.into(),
	23	reason: reason.into(),
	24	}
	25	}
	26	}
	27
	28	impl fmt::Display for DomainError {
	29	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	30	match self {
	31	Self::Validation { field, reason } => write!(f, "invalid {field}: {reason}"),
	32	Self::NotFound { entity } => write!(f, "{entity} not found"),
	33	Self::AlreadyExists { entity } => write!(f, "{entity} already exists"),
	34	Self::InvalidCredentials => f.write_str("invalid credentials"),
	35	}
	36	}
	37	}
	38
	39	impl std::error::Error for DomainError {}