gofumpt
GO111MODULE=on 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:
GO111MODULE=on go get mvdan.cc/gofumpt/gofumports
Most of the Go source files in this repository belong to the Go project.
The added formatting rules are in the format package.
Added rules
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 should use newlines consistently
example
// A newline before or after an element requires newlines for the opening and
// closing braces.
var ints = []int{1, 2,
3, 4}
// A newline between consecutive elements requires a newline between all
// elements.
var matrix = [][]int{
{1},
{2}, {
3,
},
}
var ints = []int{
1, 2,
3, 4,
}
var matrix = [][]int{
{1},
{2},
{
3,
},
}
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"
The -s code simplification flag is enabled by default
example
var _ = [][]int{[]int{1}}
var _ = [][]int{{1}}
Octal integer literals should use the 0o prefix on modules using Go 1.13 and later
example
const perm = 0755
const perm = 0o755
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() {}
Extra rules behind -extra
Adjacent parameters with the same type should be grouped together
example
func Foo(bar string, baz string) {}
func Foo(bar, baz string) {}
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.
