go-modern

name	go-modern
description	Apply modern Go idioms that match the repo's Go version before writing or reviewing Go code.

@go-modern

Use this skill when editing or reviewing Go in sdp.

The repo targets modern Go. Prefer standard-library idioms that are already available in the checked-in Go version.

Core Rule

Before changing Go code:

1. Detect the module Go version from go.mod or sdp-plugin/go.mod.
2. Use only language and stdlib features supported by that version.
3. Prefer standard-library modernizations that reduce custom code without changing behavior.

Prefer These Patterns

• slices.SortFunc over sort.Slice
• slices.Contains over manual membership loops
• maps.Copy or maps.Clone over manual copy loops
• strings.Cut over strings.SplitN(..., 2) or strings.Index plus slicing
• strings.CutPrefix and strings.CutSuffix over HasPrefix or HasSuffix plus trim
• min(...) and max(...) over trivial compare-and-assign blocks
• any over interface{} for parameters, locals, and variadics when behavior does not change

First-Wave Safe Changes

Use these freely in polish PRs when tests stay green:

• mechanical helper swaps (Cut, CutPrefix, SortFunc, Contains, Copy, Clone)
• removing tiny custom helpers now replaced by stdlib
• local interface{} to any updates
• comments or docs that replace outdated Go guidance such as golint

Avoid In The First Pass

Do not batch risky modernizations into a style PR:

• context plumbing solely to replace exec.Command with exec.CommandContext
• wide JSON tag changes such as omitempty to omitzero
• concurrency rewrites (wg.Go, atomics, cancellation semantics) unless the feature already needs them
• broad repo-wide interface{} churn across public structs or serialized payloads

Review Checklist

When reviewing Go changes, ask:

1. Is there a standard-library helper that makes this code shorter and clearer?
2. Is the rewrite behavior-preserving and easy to verify?
3. Is the new idiom supported by the module's Go version?
4. Does the change remove custom parsing, sorting, or copying logic instead of adding abstraction?

Verification

After modernization changes:

• run package tests for touched areas
• run go build ./..., go test ./..., and go vet ./...
• run golangci-lint run ./... where configured
• use golangci-lint run --enable-only modernize --issues-exit-code 0 ./... for audit snapshots

Recovery

Symptom	Fix
Skill produces no output	Check working directory is project root with docs/workstreams/backlog/
"checkpoint not found"	Run sdp-orchestrate --feature <ID> to create initial checkpoint
"workstream files missing"	Run sdp-orchestrate --index to verify, then @feature to regenerate
Skill hangs / no progress	Check .sdp/log/events.jsonl for last event; use sdp reset --feature <ID> if stuck
Review loop exceeds 3 rounds	Use @review --override "reason", @review --partial, or @review --escalate

See Also

• @build - implementation workflow
• @review - multi-agent review
• CONTRIBUTING.md - repository code style
• DEVELOPMENT.md - local verification flow