NOTE
Errors in Go
Explicit error returns, wrapping, classification, inspection, and preserving operational context.
This is a historical learning note and may contain outdated or incomplete understanding.
Go represents ordinary failures as values implementing error. Callers handle them explicitly, and wrapping with %w can preserve a causal chain for errors.Is/errors.As inspection.
Return enough context to diagnose the operation while preserving stable machine-checkable error categories. Do not compare formatted error strings as an API contract. Panic is reserved for exceptional unrecoverable programmer/runtime situations, not routine I/O or validation failures.