| name | go-modern |
| description | Write idiomatic, modern Go (1.25+/1.26) using current language and stdlib features. Use when authoring or reviewing Go code, choosing between stdlib and third-party helpers, working with generics, iterators, contexts, or error wrapping in this workspace. |
Modern Go
Write Go that reads like the standard library: small, explicit, and boring in
the best way. Target the workspace Go version (1.25+/1.26).
When to use
- Implementing or refactoring Go packages, services, or CLIs.
- Reviewing Go for idiomatic style and current stdlib usage.
- Deciding between stdlib, a RonyKIT
x/* helper, and a third-party package.
Core idioms
- Accept interfaces, return structs. Keep interfaces small and defined by the
consumer, not the producer.
- Errors: wrap with
fmt.Errorf("...: %w", err); inspect with errors.Is /
errors.As. In this workspace prefer rony/errs for domain errors.
- Context first.
ctx context.Context is the first parameter; never store it
in a struct. Honor cancellation and deadlines.
- Zero values are useful. Design types so the zero value is ready to use.
- Generics for containers/algorithms only. Don't reach for type parameters
when a concrete type or a small interface is clearer.
Use current stdlib
- Iterators (
iter.Seq, range-over-func), slices, maps, cmp for
collection work instead of hand-rolled loops.
min/max/clear builtins.for i := range n for counted loops.errors.Join to combine multiple failures.context.WithoutCancel, WithDeadlineCause, and AfterFunc where they fit.log/slog for structured logging (or the workspace x/telemetry/logkit).
Package selection (this workspace)
Before importing a third-party or stdlib helper, check for a RonyKIT
equivalent: IDs/JSON-byte casts/string↔number/case/collections → x/rkit;
config → x/settings; DI → x/di; errors → rony/errs; logging →
x/telemetry/logkit. Durable workflows: flow only — never import
go.temporal.io/sdk directly. See knowledge://ronyup/architecture/package-selection.
Concurrency
- Start a goroutine only when you control its lifetime and shutdown.
- Prefer
errgroup / bounded worker pools over unbounded go calls.
- Protect shared state with the smallest possible critical section; prefer
channels for ownership transfer, mutexes for protecting fields.
- Always test with
-race for concurrent code.
Checklist before "done"
gofmt/goimports clean, go vet passes, golangci-lint clean.- No naked
panic in library code; errors returned and wrapped.
- Exported identifiers have doc comments starting with the identifier name.
