/golang-language

name: golang-language
description: Core idioms, style guides, and best practices for writing idiomatic Go code. Use when writing Go code following official style guides and idiomatic patterns.
metadata:
  triggers:
    files:
    - 'go.mod'
    keywords:
    - golang
    - go code
    - idiomatic
    - gofmt
    - goimports
    - iota
    - golang style

Golang Language Standards

**Priority: P0 (CRITICAL)**

Guidelines

• **Formatting**: Run **`gofmt`** or **`goimports`** on save. Use **`gopls`** for LSP features.
• **Naming**: Use **`camelCase`** for internal (unexported) and **`PascalCase`** for public (exported) symbols.
• **Packages**: Use short, lowercase, singular names (e.g., **`http`**, **`user`**). Avoid `_` or `camelCase` in package names.
• **Interfaces**: Small interfaces — 1-2 methods max. Define where used (consumer side), not where implemented.
• **Errors**: Return **`error`** as last return value. Handle errors **immediately** at call-site.
• **Slices**: Use **`make(slice, len, cap)`** to pre-allocate capacity and avoid redundant re-allocations.
• **Enums**: Use const block with iota for type-safe enumerations.
• **Zero Values**: Leverage **`zero-value`** initialization over explicit `nil` checks where possible.

Anti-Patterns

• **No init**: Use constructors (NewService()), not init(). (not init() — it runs implicitly and makes testing harder)
• **No Globals**: Use DI, not global mutable state.
• **No `panic`**: Return errors, don't panic.
• **No `_` ignored errors**: Always check and handle errors.
• **No stutter**: `log.Error`, not `log.LogError`.

Verification Workflow (Mandatory)

After writing or modifying Go code:

1. **`mcp__ide__getDiagnostics`** — catch compile errors and gopls type diagnostics immediately 2. **`go vet ./...`** — catch common mistakes (printf mismatches, unreachable code, shadowed vars) 3. **`goimports -w .`** — fix imports and formatting in one pass

References

• [Idioms](references/idioms.md)
• [Effective Go Summary](references/effective-go-summary.md)