Go Patterns Skill

Umbrella skill for Go development: Google style, testing, concurrency, error handling, failure modes, code review, SAP CC conventions, and quality gates. Load the references relevant to the task.

Google Style Precedence

Use this precedence when guidance differs:

1. The target repository's explicit rules and required compatibility constraints.
2. The Google Go Style Guide's canonical rules.
3. Google Go Style Decisions' normative guidance.
4. Google Go Style Best Practices' non-canonical recommendations.
5. Task-specific references below.

Prefer local consistency only where the Google guide allows judgment. Do not create unrelated churn merely to restyle existing code. For new and nearby changed code, follow the current pinned guidance. Record a conscious exception when repository rules, generated-code constraints, or compatibility requirements require one.

Reference Loading Table

Signal	Load These Files	Why
Google-specific style decisions	Relevant sections under google-style-guide/	Check the pinned conventions needed for the task
Testing	testing.md	Writing, fixing, or reviewing Go tests
Concurrency	concurrency.md	Goroutines, channels, sync primitives, race conditions
Error handling	error-handling.md	Error wrapping, sentinels, custom types, errors.Is/As
Review patterns	preferred-patterns.md	Detecting code smells, over-engineering, bad Go patterns
Code review	code-review.md	Reviewing Go code or PRs for quality
SAP CC conventions	sapcc-conventions.md	Working in sapcc/* repos with go-bits
Quality gate	quality-gate.md	Running make check, linting, pre-commit validation

Instructions

Step 1: Identify the Go Domain

Classify the task into one or more domains, then load the corresponding reference files. Only load what is needed -- do not load all references for every task.

Domain	Load Reference	When
Testing	references/testing.md	Writing, fixing, or reviewing Go tests
Concurrency	references/concurrency.md	Goroutines, channels, sync primitives, race conditions
Error handling	references/error-handling.md	Error wrapping, sentinels, custom types, errors.Is/As
Review patterns	references/preferred-patterns.md	Detecting code smells, over-engineering, bad Go patterns
Code review	references/code-review.md	Reviewing Go code or PRs for quality
SAP CC conventions	references/sapcc-conventions.md	Working in sapcc/* repos with go-bits
Quality gate	references/quality-gate.md	Running make check, linting, pre-commit validation

Multiple domains may apply. For example, reviewing a PR that includes concurrency code should load both code-review.md and concurrency.md.

Step 2: Load and Follow the Reference

Read the selected reference file(s) using ${CLAUDE_SKILL_DIR}/references/<name>.md. Each reference contains the full methodology, phases, code examples, and error handling for that domain. Follow the instructions in the reference as if they were this skill's instructions.

Step 3: Use Domain-Specific Sub-References

Some references point to their own sub-reference files for extended patterns:

Testing sub-references:

• ${CLAUDE_SKILL_DIR}/references/testing/go-test-patterns.md -- Full table-driven test, helper, mock examples
• ${CLAUDE_SKILL_DIR}/references/testing/go-benchmark-and-concurrency.md -- b.Loop() benchmarks, synctest

Concurrency sub-references:

• ${CLAUDE_SKILL_DIR}/references/concurrency/concurrency-patterns.md -- Worker pool, fan-out/fan-in, pipeline, rate limiter, graceful shutdown

Error handling sub-references:

• ${CLAUDE_SKILL_DIR}/references/error-handling/patterns.md -- gopls tracing, HTTP handler patterns, error wrapping in middleware

Review-pattern sub-references:

• ${CLAUDE_SKILL_DIR}/references/preferred-patterns/code-examples.md -- Extended before/after for all 7 failure modes

Code review sub-references:

• ${CLAUDE_SKILL_DIR}/references/code-review/common-review-comments.md -- Go code patterns with good/bad examples

SAP CC conventions sub-references:

• ${CLAUDE_SKILL_DIR}/references/sapcc-conventions/sapcc-code-patterns.md -- Primary reference: code patterns, testing patterns, failure modes (merged from testing-patterns-detailed.md and preferred-patterns.md)
• ${CLAUDE_SKILL_DIR}/references/sapcc-conventions/library-reference.md -- Complete approved/restricted library table
• ${CLAUDE_SKILL_DIR}/references/sapcc-conventions/architecture-patterns.md -- Full 102-rule architecture spec
• ${CLAUDE_SKILL_DIR}/references/sapcc-conventions/review-standards.md -- Lead + secondary review standards (merged)
• ${CLAUDE_SKILL_DIR}/references/sapcc-conventions/extended-patterns.md -- Security, K8s, PR hygiene patterns
• Plus: api-design-detailed.md, build-ci-detailed.md, error-handling-detailed.md, go-bits-philosophy-detailed.md, pr-mining-insights.md

Quality gate sub-references:

• ${CLAUDE_SKILL_DIR}/references/quality-gate/common-lint-errors.json -- Linter descriptions and fix suggestions
• ${CLAUDE_SKILL_DIR}/references/quality-gate/makefile-targets.json -- Available make targets
• ${CLAUDE_SKILL_DIR}/references/quality-gate/expert-review-patterns.md -- Manual review patterns
• ${CLAUDE_SKILL_DIR}/references/quality-gate/examples.md -- Detailed usage examples

Step 4: Execute

Follow the loaded reference methodology. Each reference has its own phases, gates, and completion criteria. Apply them as written.

Available Scripts

Scripts are organized by domain in sub-directories:

• Testing: scripts/gen-table-test.sh, scripts/bench-compare.sh
• Error handling: scripts/check-errors.sh
• Code review: scripts/check-interface-compliance.sh
• SAP CC conventions: scripts/check-sapcc-identify-endpoint.sh, scripts/check-sapcc-auth-ordering.sh, scripts/check-sapcc-json-strict.sh, scripts/check-sapcc-time-now.sh, scripts/check-sapcc-httptest.sh, scripts/check-sapcc-todo-format.sh
• Quality gate: scripts/quality_checker.py, scripts/validate.py
• Google style snapshot: scripts/sync-google-style-guide.py (pinned upstream refresh; requires review before revision changes)

Error Handling

Errors are domain-specific. Load the relevant reference file and check its Error Handling section for troubleshooting guidance.