Code Quality Basics

10 examples to get you started with Go code quality - 7 basic and 3 intermediate.

Prerequisites

• Install Go 1.26.x or later from go.dev/dl.
• Create a module: mkdir quality && cd quality && go mod init example.com/quality.
• Install helpers: go install golang.org/x/tools/cmd/goimports@latest and go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest.

Basic Examples

1. gofmt in place

Rewrite a file to canonical Go formatting.

gofmt -w main.go

package main
 
import "fmt"
 
func main() {fmt.Println("hello")}

After gofmt -w, spacing and indentation match community style.

• gofmt is deterministic: same input always yields same output.
• CI often runs test -z "$(gofmt -l .)" to fail on drift.
• There is no project-level format config to maintain.

Related: gofmt & goimports Enforcement - team formatting policy

2. goimports for imports

Format and fix import blocks in one step.

goimports -w .

package main
 
import "fmt"
 
func main() {
    fmt.Println(time.Now()) // missing import before goimports
}

• goimports adds missing stdlib imports and removes unused ones.
• Use -local example.com/quality to group your module paths separately.
• Editors often run goimports on save via gopls.

Related: gofmt & goimports Enforcement - -local grouping

3. go vet on all packages

Run built-in analyzers across the module.

go vet ./...

package main
 
import "fmt"
 
func main() {
    fmt.Printf("%d", "not-a-number") // vet: Printf format mismatch
}

• Vet reports issues the compiler accepts but are likely bugs.
• Run in CI on every PR; zero findings should be the default.
• New Go releases may add vet checks - read release notes.

Related: go vet & Common Analyzer Diagnostics - common messages

4. Minimal test gate

Quality includes behavior, not just static checks.

go test ./...

package add
 
func Sum(a, b int) int { return a + b }

package add_test
 
import "testing"
 
func TestSum(t *testing.T) {
    if got := add.Sum(2, 3); got != 5 {
        t.Fatalf("got %d", got)
    }
}

• Tests live in *_test.go files in the same package (or _test external package).
• go test compiles tests with the race detector when you pass -race.
• Failing tests should block merge before linter debates matter.

Related: CI Quality Gates: Lint, Test, Race, Vuln - full pipeline

5. List unformatted files

Check formatting without writing files (CI-friendly).

gofmt -l .

• Empty output means every .go file is formatted.
• Non-empty output lists paths that need gofmt -w.
• Pair with git diff --exit-code after format in pre-commit hooks.

Related: Pre-commit Hooks & Review Checklists - local automation

6. golangci-lint first run

Run the standard linter bundle.

golangci-lint run ./...

• First run downloads analyzer binaries; pin version in CI for reproducibility.
• Start with default linters; tune .golangci.yml after baseline is green.
• Fix vet-class issues before chasing style nits.

Related: golangci-lint Configuration - config file patterns

7. Makefile check target

One command for contributors.

.PHONY: check
check:
	gofmt -l . | tee /tmp/gofmt.out && test ! -s /tmp/gofmt.out
	go vet ./...
	go test ./...

make check

• Document make check in README and CONTRIBUTING.
• Expand with golangci-lint run when the team is ready.
• Keep targets fast enough for pre-push hooks (< 2 minutes on laptops).

Related: Linting & Code Quality Best Practices - adoption pacing

Intermediate Examples

8. Race detector in tests

Catch data races that vet misses.

go test -race ./...

package counter
 
import "sync"
 
type Counter struct {
    mu sync.Mutex
    n  int
}
 
func (c *Counter) Inc() {
    c.mu.Lock()
    c.n++
    c.mu.Unlock()
}

• -race slows tests and needs more memory; run in CI, not every save.
• Race failures include goroutine stacks - fix by adding synchronization.
• HTTP handlers sharing mutable state without locks are a common trigger.

Related: CI Quality Gates: Lint, Test, Race, Vuln - when to require race

9. go mod tidy check

Keep module metadata consistent.

go mod tidy
git diff --exit-code go.mod go.sum

• Fails CI when dependencies drift without committed go.sum updates.
• Run after dependency bumps and before tagging releases.
• Pair with govulncheck for security scanning on the tidy graph.

Related: govulncheck for Dependency Vulnerabilities - CVE scanning

10. Simple pre-commit script

Block commits that fail fast checks.

#!/usr/bin/env bash
set -euo pipefail
gofmt -l . | grep . && { echo "run gofmt -w"; exit 1; } || true
go vet ./...
go test ./...

chmod +x scripts/pre-commit.sh
# wire with: ln -s ../../scripts/pre-commit.sh .git/hooks/pre-commit

• Hooks catch issues before CI queue time.
• Keep hooks fast; defer golangci-lint to CI if it exceeds ~60s locally.
• Document bypass policy (--no-verify) for emergencies only.

Related: Pre-commit Hooks & Review Checklists - hook templates

Stack versions: This page was written for Go 1.26.x (Green Tea GC default, go fix modernizers - verify patch at build), chi (latest - verify at build), gin (latest - verify at build), echo (latest - verify at build), google.golang.org/grpc (latest - verify at build), sigs.k8s.io/controller-runtime (latest - verify at build), kubebuilder (latest - verify at build), tinygo (latest - verify board targets at build), wazero (latest - verify at build), and golangci-lint (latest - verify linter set at build). Y29kZWd1aWRlcy5pb3xjZ2lvNDUwfDIwMjYwNw==