golang-naming

Community default. A company skill that explicitly supersedes samber/cc-skills-golang@golang-naming skill takes precedence. Go Naming Conventions Go favors short, readable names. Capitalization controls visibility — uppercase is exported, lowercase is unexported. All identifiers MUST use MixedCaps, NEVER underscores. "Clear is better than clever." — Go Proverbs "Design the architecture, name the components, document the details." — Go Proverbs To ignore a rule, just add a comment to the code. Quick Reference Element Convention Example Package lowercase, single word, _test suffix OK for test files json , http , tabwriter , http_test File lowercase, underscores OK user_handler.go Exported name UpperCamelCase ReadAll , HTTPClient Unexported lowerCamelCase parseToken , userCount Interface method name + -er Reader , Closer , Stringer Struct MixedCaps noun Request , FileHeader Constant MixedCaps (not ALL_CAPS) MaxRetries , defaultTimeout Receiver 1-2 letter abbreviation func (s Server) , func (b Buffer) Error variable Err prefix ErrNotFound , ErrTimeout Error type Error suffix PathError , SyntaxError Constructor New (single type) or NewTypeName (multi-type) ring.New , http.NewRequest Boolean field is , has , can prefix on fields and methods isReady , IsConnected() Test function Test + function name TestParseToken Acronym all caps or all lower URL , HTTPServer , xmlParser Variant: context WithContext suffix FetchWithContext , QueryContext Variant: in-place In suffix SortIn() , ReverseIn() Variant: error Must prefix MustParse() , MustLoadConfig() Option func With + field name WithPort() , WithLogger() Enum (iota) type name prefix, zero-value = unknown StatusUnknown at 0, StatusReady Named return descriptive, for docs only (n int, err error) Error string lowercase (incl. acronyms), no punctuation "image: unknown format" , "invalid id" Import alias short, only on collision mrand "math/rand" , pb "app/proto" Format func f suffix Errorf , Wrapf , Logf Test table fields got / expected prefixes input string , expected int MixedCaps All 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. // ✓ Good MaxPacketSize userCount parseHTTPResponse // ✗ Bad — these conventions conflict with Go's export mechanism and tooling expectations MAX_PACKET_SIZE // C/Python style max_packet_size // snake_case kMaxBufferSize // Hungarian notation Avoid Stuttering Go 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. // Good — clean at the call site http . Client // not http.HTTPClient json . Decoder // not json.JSONDecoder user . New ( ) // not user.NewUser() config . Parse ( ) // not config.ParseConfig() // In package sqldb: type Connection struct { } // not DBConnection — "db" is already in the package name // Anti-stutter applies to ALL exported types, not just the primary struct: // In package dbpool: type Pool struct { } // not DBPool type Status struct { } // not PoolStatus — callers write dbpool.Status type Option func ( * Pool ) // not PoolOption Frequently Missed Conventions These conventions are correct but non-obvious — they are the most common source of naming mistakes: 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 ). 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. 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") . 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. 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" . Detailed Categories For complete rules, examples, and rationale, see: Packages, Files & Import Aliasing — Package naming (single word, lowercase, no plurals), file naming conventions, import alias patterns (only use on collision to avoid cognitive load), and directory structure. Variables, Booleans, Receivers & Acronyms — 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). Functions, Methods & Options — 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 ). Types, Constants & Errors — 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). Test Naming — Test function naming ( TestFunctionName ), table-driven test field conventions ( input , expected ), test helper naming, and subcase naming patterns. Common Mistakes Mistake Fix ALL_CAPS constants Go reserves casing for visibility, not emphasis — use MixedCaps ( MaxRetries ) 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 Url , Http , Json acronyms Mixed-case acronyms create ambiguity ( HttpsUrl — is it Https+Url ?). Use all caps or all lower this or self receiver Go methods are called frequently — use 1-2 letter abbreviation ( s for Server ) to reduce visual noise util , helper packages These names say nothing about content — use specific names that describe the abstraction http.HTTPClient stuttering Package name is always present at call site — http.Client avoids reading "HTTP" twice user.NewUser() constructor Single primary type uses New() — user.New() avoids repeating the type name connected bool field Bare adjective is ambiguous — use isConnected so the field reads as a true/false question "invalid message ID" error Error strings must be fully lowercase including acronyms — "invalid message id" StatusReady at iota 0 Zero value should be a sentinel — StatusUnknown at 0 catches uninitialized values "not found" error string Sentinel errors should include the package name — "mypackage: not found" identifies the origin userSlice type-in-name Types encode implementation detail — users describes what it holds, not how Inconsistent receiver names Switching names across methods of the same type confuses readers — use one name consistently snake_case identifiers Underscores conflict with Go's MixedCaps convention and tooling expectations — use mixedCaps Long names for short scopes Name length should match scope — i is fine for a 3-line loop, userIndex is noise Naming constants by value Values change, roles don't — DefaultPort survives a port change, Port8080 doesn't FetchCtx() context variant WithContext is the standard Go suffix — FetchWithContext() is instantly recognizable sort() in-place but no In Readers assume functions return new values. SortIn() signals mutation parse() panicking on error MustParse() warns callers that failure panics — surprises belong in the name Mixing With , Set , Use Consistency across the codebase — With is the Go convention for functional options Plural package names Go convention is singular ( net/url not net/urls ) — keeps import paths consistent Wrapf without f suffix The f suffix signals format-string semantics — Wrapf , Errorf tell callers to pass format args Unnecessary import aliases Aliases add cognitive load. Only alias on collision — mrand "math/rand" Inconsistent concept names Using user / account / person for the same concept forces readers to track synonyms — pick one name Enforce with Linters Many naming convention issues are caught automatically by linters: revive , predeclared , misspell , errname . See samber/cc-skills-golang@golang-linter skill for configuration and usage. Cross-References → See samber/cc-skills-golang@golang-code-style skill for broader formatting and style decisions → See samber/cc-skills-golang@golang-structs-interfaces skill for interface naming depth and receiver design → See samber/cc-skills-golang@golang-linter skill for automated enforcement (revive, predeclared, misspell, errname)