Using go fmt and go vet

Formatting Code with go fmt

'go fmt' rewrites your source files in place to match Go's one true formatting style: consistent indentation, spacing, and brace placement. Because everyone's code ends up looking the same, code reviews can focus on logic instead of arguing over tabs versus spaces.

Note: Most editors run gofmt automatically on save once Go tooling is configured.

Example: Formatting Code with go fmt

go fmt ./...

What gofmt Actually Changes

Running gofmt on a file adjusts indentation to tabs, aligns struct fields and comments, and normalizes spacing around operators, without altering what the program does. It's purely cosmetic but mandatory by community convention -- almost all published Go code is gofmt-clean.

Example: What gofmt Actually Changes

package main

import "fmt"

func main() {
	fmt.Println("gofmt normalizes spacing, indentation, and alignment")
}

Catching Bugs with go vet

'go vet' examines your code for constructs that compile fine but are probably bugs, like a fmt.Printf call whose format string doesn't match its arguments, or a struct tag with invalid syntax. It's a lightweight static analysis pass that catches mistakes before they reach production.

Note: 'go vet' is often run automatically as part of 'go test'.

Example: Catching Bugs with go vet

go vet ./...

A vet-Catchable Mistake

A classic example vet flags is passing the wrong number or type of arguments to a Printf-style function -- the code compiles because Printf accepts any arguments, but the output would be wrong at runtime. Running vet regularly catches this class of error immediately.

Example: A vet-Catchable Mistake

package main

import "fmt"

func main() {
	name := "Gopher"
	age := 5
	fmt.Printf("%s is %d years old\n", name, age)
}