golang-naming

SKILL.md

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-lint 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-lint skill for automated enforcement (revive, predeclared, misspell, errname)