README.md

masterror-derive

Procedural macros that power masterror's #[derive(Error)]. The derive generates ergonomic std::error::Error and Display implementations together with seamless integration into masterror's domain-centric AppError type.

Tip: Depend on the masterror crate in application code and import the macros from there (use masterror::Error;). This standalone crate is published to make cargo install/cargo package flows happy and to support advanced macro integrations.

Quick start

[dependencies]
masterror = "0.10"

use masterror::{AppError, Error};

#[derive(Error)]
#[error(display = "failed to parse payload: {source}")]
#[app_error(kind = "BadRequest")]
pub struct PayloadInvalid {
    #[source]
    pub source: serde_json::Error,
}

fn parse(input: &str) -> Result<(), AppError> {
    serde_json::from_str::<serde_json::Value>(input)
        .map(|_| ())
        .map_err(PayloadInvalid::from)
}

The derive implements Display, std::error::Error, and conversion glue so you can return rich AppError values with a single ?.

Supported attributes

• #[error(display = ...)] – formats the error message using captured fields.
• #[source] / #[from] – wires source error propagation and conversion.
• #[backtrace] – exposes an optional captured Backtrace.
• #[app_error(...)] – configures how the error maps into AppError (kind, HTTP status, telemetry).
• #[provide(...)] – attaches structured telemetry providers that surface typed context (IDs, domains, tenant information) through tracing layers.

See the main masterror README for an end-to-end guide and advanced examples covering templated display strings, telemetry providers and OpenAPI/schema integrations.

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be licensed as above, without any additional terms or conditions.