10. Revised error handling using miette

Date: 2025-07-31

Status

Accepted

Context

ADR 0007 introduced an error handling scheme using anyhow and thiserror.

This had several issues:

• error messages lacked context
• the task of implementing it was rather intensive (and not yet complete)

Decision

Use miette as the means of error handling, following the usage guide.

In short:

• use miette::Result<T> as the default return type of fallible operations
• use into_diagnostic() to convert errors
• use with_context() as appropriate
• enable the fancy feature on binary crates
• continue to use thiserror as appropriate
• remove all use of anyhow

Consequences

• error messages will include context, making them more useful in diagnosing problems
• less code will be required compared to ADR 0007