Golang Naming

1---2name: golang-naming3description: "Go (Golang) naming conventions — covers packages, constructors, structs, interfaces, constants, enums, errors, booleans, receivers, getters/setters, functional options, acronyms, test functions, and subtest names. Use this skill when writing new Go code, reviewing or refactoring, choosing between naming alternatives (New vs NewTypeName, isConnected vs connected, ErrNotFound vs NotFoundError, StatusReady vs StatusUnknown at iota 0), debating Go package names (utils/helpers anti-patterns), or asking about Go naming best practices. Also trigger when the user mentions MixedCaps vs snake_case, ALL_CAPS constants, Get-prefix on getters, or error string casing. Do NOT use for general Go implementation questions that don't involve naming decisions."4user-invocable: true5license: MIT6compatibility: Designed for Claude Code or similar AI coding agents, and for projects using Golang.7metadata:8  author: samber9  version: "1.1.1"10  openclaw:11    emoji: "🏷️"12    homepage: https://github.com/samber/cc-skills-golang13    requires:14      bins:15        - go16    install: []17allowed-tools: Read Edit Write Glob Grep Bash(go:*) Bash(golangci-lint:*) Bash(git:*) Agent18---19 20> **Community default.** A company skill that explicitly supersedes `samber/cc-skills-golang@golang-naming` skill takes precedence.21 22# Go Naming Conventions23 24Go favors short, readable names. Capitalization controls visibility — uppercase is exported, lowercase is unexported. All identifiers MUST use MixedCaps, NEVER underscores.25 26> "Clear is better than clever." — Go Proverbs27>28> "Design the architecture, name the components, document the details." — Go Proverbs29 30To ignore a rule, just add a comment to the code.31 32## Quick Reference33 34| Element | Convention | Example |35| --- | --- | --- |36| Package | lowercase, single word, _test suffix OK for test files | `json`, `http`, `tabwriter`, `http_test` |37| File | lowercase, underscores OK | `user_handler.go` |38| Exported name | UpperCamelCase | `ReadAll`, `HTTPClient` |39| Unexported | lowerCamelCase | `parseToken`, `userCount` |40| Interface | method name + `-er` | `Reader`, `Closer`, `Stringer` |41| Struct | MixedCaps noun | `Request`, `FileHeader` |42| Constant | MixedCaps (not ALL_CAPS) | `MaxRetries`, `defaultTimeout` |43| Receiver | 1-2 letter abbreviation | `func (s *Server)`, `func (b *Buffer)` |44| Error variable | `Err` prefix | `ErrNotFound`, `ErrTimeout` |45| Error type | `Error` suffix | `PathError`, `SyntaxError` |46| Constructor | `New` (single type) or `NewTypeName` (multi-type) | `ring.New`, `http.NewRequest` |47| Boolean field | `is`, `has`, `can` prefix on **fields** and methods | `isReady`, `IsConnected()` |48| Test function | `Test` + function name | `TestParseToken` |49| Acronym | all caps or all lower | `URL`, `HTTPServer`, `xmlParser` |50| Variant: context | `WithContext` suffix | `FetchWithContext`, `QueryContext` |51| Variant: in-place | `In` suffix | `SortIn()`, `ReverseIn()` |52| Variant: error | `Must` prefix | `MustParse()`, `MustLoadConfig()` |53| Option func | `With` + field name | `WithPort()`, `WithLogger()` |54| Enum (iota) | type name prefix, zero-value = unknown | `StatusUnknown` at 0, `StatusReady` |55| Named return | descriptive, for docs only | `(n int, err error)` |56| Error string | lowercase (incl. acronyms), no punctuation | `"image: unknown format"`, `"invalid id"` |57| Import alias | short, only on collision | `mrand "math/rand"`, `pb "app/proto"` |58| Format func | `f` suffix | `Errorf`, `Wrapf`, `Logf` |59| Test table fields | `got`/`expected` prefixes | `input string`, `expected int` |60 61## MixedCaps62 63All Go identifiers MUST use `MixedCaps` (or `mixedCaps`). NEVER use underscores in identifiers — the only exceptions are test function subcases (`TestFoo_InvalidInput`), generated code, and OS/cgo interop. This is load-bearing, not cosmetic — Go's export mechanism relies on capitalization, and tooling assumes MixedCaps throughout.64 65```go66// ✓ Good67MaxPacketSize68userCount69parseHTTPResponse70 71// ✗ Bad — these conventions conflict with Go's export mechanism and tooling expectations72MAX_PACKET_SIZE   // C/Python style73max_packet_size   // snake_case74kMaxBufferSize    // Hungarian notation75```76 77## Avoid Stuttering78 79Go call sites always include the package name, so repeating it in the identifier wastes the reader's time — `http.HTTPClient` forces parsing "HTTP" twice. A name MUST NOT repeat information already present in the package name, type name, or surrounding context.80 81```go82// Good — clean at the call site83http.Client       // not http.HTTPClient84json.Decoder      // not json.JSONDecoder85user.New()        // not user.NewUser()86config.Parse()    // not config.ParseConfig()87 88// In package sqldb:89type Connection struct{}  // not DBConnection — "db" is already in the package name90 91// Anti-stutter applies to ALL exported types, not just the primary struct:92// In package dbpool:93type Pool struct{}        // not DBPool94type Status struct{}      // not PoolStatus — callers write dbpool.Status95type Option func(*Pool)   // not PoolOption96```97 98## Frequently Missed Conventions99 100These conventions are correct but non-obvious — they are the most common source of naming mistakes:101 102**Constructor naming:** When a package exports a single primary type, the constructor is `New()`, not `NewTypeName()`. This avoids stuttering — callers write `apiclient.New()` not `apiclient.NewClient()`. Use `NewTypeName()` only when a package has multiple constructible types (like `http.NewRequest`, `http.NewServeMux`).103 104**Boolean struct fields:** Unexported boolean fields MUST use `is`/`has`/`can` prefix — `isConnected`, `hasPermission`, not bare `connected` or `permission`. The exported getter keeps the prefix: `IsConnected() bool`. This reads naturally as a question and distinguishes booleans from other types.105 106**Error strings are fully lowercase — including acronyms.** Write `"invalid message id"` not `"invalid message ID"`, because error strings are often concatenated with other context (`fmt.Errorf("parsing token: %w", err)`) and mixed case looks wrong mid-sentence. Sentinel errors should include the package name as prefix: `errors.New("apiclient: not found")`.107 108**Enum zero values:** Always place an explicit `Unknown`/`Invalid` sentinel at iota position 0. A `var s Status` silently becomes 0 — if that maps to a real state like `StatusReady`, code can behave as if a status was deliberately chosen when it wasn't.109 110**Subtest names:** Table-driven test case names in `t.Run()` should be fully lowercase descriptive phrases: `"valid id"`, `"empty input"` — not `"valid ID"` or `"Valid Input"`.111 112## Detailed Categories113 114For complete rules, examples, and rationale, see:115 116- **[Packages, Files & Import Aliasing](./references/packages-files.md)** — Package naming (single word, lowercase, no plurals), file naming conventions, import alias patterns (only use on collision to avoid cognitive load), and directory structure.117 118- **[Variables, Booleans, Receivers & Acronyms](./references/identifiers.md)** — Scope-based naming (length matches scope: `i` for 3-line loops, longer names for package-level), single-letter receiver conventions (`s` for Server), acronym casing (URL not Url, HTTPServer not HttpServer), and boolean naming patterns (isReady, hasPrefix).119 120- **[Functions, Methods & Options](./references/functions-methods.md)** — Getter/setter patterns (Go omits `Get` so `user.Name()` reads naturally), constructor conventions (`New` or `NewTypeName`), named returns (for documentation only), format function suffixes (`Errorf`, `Wrapf`), and functional options (`WithPort`, `WithLogger`).121 122- **[Types, Constants & Errors](./references/types-errors.md)** — Interface naming (`Reader`, `Closer` suffix with `-er`), struct naming (nouns, MixedCaps), constants (MixedCaps, not ALL_CAPS), enums (type name prefix like `StatusReady`), sentinel errors (`ErrNotFound` variables), error types (`PathError` suffix), and error message conventions (lowercase, no punctuation).123 124- **[Test Naming](./references/testing.md)** — Test function naming (`TestFunctionName`), table-driven test field conventions (`input`, `expected`), test helper naming, and subcase naming patterns.125 126## Common Mistakes127 128| Mistake | Fix |129| --- | --- |130| `ALL_CAPS` constants | Go reserves casing for visibility, not emphasis — use `MixedCaps` (`MaxRetries`) |131| `GetName()` getter | Go omits `Get` because `user.Name()` reads naturally at call sites. But `Is`/`Has`/`Can` prefixes are kept for boolean predicates: `IsHealthy() bool` not `Healthy() bool` |132| `Url`, `Http`, `Json` acronyms | Mixed-case acronyms create ambiguity (`HttpsUrl` — is it `Https+Url`?). Use all caps or all lower |133| `this` or `self` receiver | Go methods are called frequently — use 1-2 letter abbreviation (`s` for `Server`) to reduce visual noise |134| `util`, `helper` packages | These names say nothing about content — use specific names that describe the abstraction |135| `http.HTTPClient` stuttering | Package name is always present at call site — `http.Client` avoids reading "HTTP" twice |136| `user.NewUser()` constructor | Single primary type uses `New()` — `user.New()` avoids repeating the type name |137| `connected bool` field | Bare adjective is ambiguous — use `isConnected` so the field reads as a true/false question |138| `"invalid message ID"` error | Error strings must be fully lowercase including acronyms — `"invalid message id"` |139| `StatusReady` at iota 0 | Zero value should be a sentinel — `StatusUnknown` at 0 catches uninitialized values |140| `"not found"` error string | Sentinel errors should include the package name — `"mypackage: not found"` identifies the origin |141| `userSlice` type-in-name | Types encode implementation detail — `users` describes what it holds, not how |142| Inconsistent receiver names | Switching names across methods of the same type confuses readers — use one name consistently |143| `snake_case` identifiers | Underscores conflict with Go's MixedCaps convention and tooling expectations — use `mixedCaps` |144| Long names for short scopes | Name length should match scope — `i` is fine for a 3-line loop, `userIndex` is noise |145| Naming constants by value | Values change, roles don't — `DefaultPort` survives a port change, `Port8080` doesn't |146| `FetchCtx()` context variant | `WithContext` is the standard Go suffix — `FetchWithContext()` is instantly recognizable |147| `sort()` in-place but no `In` | Readers assume functions return new values. `SortIn()` signals mutation |148| `parse()` panicking on error | `MustParse()` warns callers that failure panics — surprises belong in the name |149| Mixing `With*`, `Set*`, `Use*` | Consistency across the codebase — `With*` is the Go convention for functional options |150| Plural package names | Go convention is singular (`net/url` not `net/urls`) — keeps import paths consistent |151| `Wrapf` without `f` suffix | The `f` suffix signals format-string semantics — `Wrapf`, `Errorf` tell callers to pass format args |152| Unnecessary import aliases | Aliases add cognitive load. Only alias on collision — `mrand "math/rand"` |153| Inconsistent concept names | Using `user`/`account`/`person` for the same concept forces readers to track synonyms — pick one name |154 155## Enforce with Linters156 157Many naming convention issues are caught automatically by linters: `revive`, `predeclared`, `misspell`, `errname`. See `samber/cc-skills-golang@golang-linter` skill for configuration and usage.158 159## Cross-References160 161- → See `samber/cc-skills-golang@golang-code-style` skill for broader formatting and style decisions162- → See `samber/cc-skills-golang@golang-structs-interfaces` skill for interface naming depth and receiver design163- → See `samber/cc-skills-golang@golang-linter` skill for automated enforcement (revive, predeclared, misspell, errname)