kybin / gofumpt

A stricter gofmt, the way it should be pronounced

gofumpt

gofmt, the way it should be pronounced.

cd $(mktemp -d); go mod init tmp; go get mvdan.cc/gofumpt

Enforce a stricter format than gofmt, while being backwards compatible. That is, gofumpt is happy with a subset of the formats that gofmt is happy with.

The tool is a modified fork of gofmt, so it can be used as a drop-in replacement. Running gofmt after gofumpt should be a no-op.

A drop-in replacement for goimports is also available:

cd $(mktemp -d); go mod init tmp; go get mvdan.cc/gofumpt/gofumports

Features

No empty lines at the beginning or end of a function

example

func foo() {
	println("bar")

}

func foo() {
	println("bar")
}

No empty lines around a lone statement (or comment) in a block

example

if err != nil {

	return err
}

if err != nil {
	return err
}

No empty lines before a simple error check

example

foo, err := processFoo()

if err != nil {
	return err
}

foo, err := processFoo()
if err != nil {
	return err
}

Composite literals with elements in separate lines must also separate both braces

example

var ints = []int{1, 2,
	3, 4}

var ints = []int{
	1, 2,
	3, 4,
}

std imports must be in a separate group at the top

example

import (
	"foo.com/bar"

	"io"

	"io/ioutil"
)

import (
	"io"
	"io/ioutil"

	"foo.com/bar"
)

Short case clauses should take a single line

example

switch c {
case 'a', 'b',
	'c', 'd':
}

switch c {
case 'a', 'b', 'c', 'd':
}

Multiline top-level declarations must be separated by empty lines

example

func foo() {
	println("multiline foo")
}
func bar() {
	println("multiline bar")
}

func foo() {
	println("multiline foo")
}

func bar() {
	println("multiline bar")
}

Single var declarations should not be grouped with parentheses

example

var (
	foo = "bar"
)

var foo = "bar"

Contiguous top-level declarations should be grouped together

example

var nicer = "x"
var with = "y"
var alignment = "z"

var (
	nicer     = "x"
	with      = "y"
	alignment = "z"

Simple var-declaration statements should use short assignments

example

var s = "somestring"

s := "somestring"

Comments which aren't Go directives should start with a whitespace

example

//go:noinline

//Foo is awesome.
func Foo() {}

//go:noinline

// Foo is awesome.
func Foo() {}

Installation

gofumpt is a replacement for gofmt, so you can simply go get it as described at the top of this README and use it.

Alternatively, to use the tool with VS Code, add these settings:

"go.formatTool": "goimports",
"go.alternateTools": {
    "goimports": "gofumports",
},
"go.languageServerExperimentalFeatures": {
    "format": false
}

You can use gofmt instead of goimports and gofumpt instead of gofumports if you don't need auto-importing on-save.

Roadmap

This tool is a place to experiment. In the long term, the features that work well might be proposed for gofmt itself.

The tool is also compatible with gofmt and is aimed to be stable, so you can rely on it for your code as long as you pin a version of it.

License

Note that much of the code is copied from Go's gofmt and goimports commands. You can tell which files originate from the Go repository from their copyright headers. Their license file is LICENSE.google.

gofumpt's original source files are also under the 3-clause BSD license, with the separate file LICENSE.