Add WSL linter

README.md

@@ -220,6 +220,7 @@ stylecheck: Stylecheck is a replacement for golint [fast: true, auto-fix: false]
 unconvert: Remove unnecessary type conversions [fast: true, auto-fix: false]
 unparam: Reports unused function parameters [fast: true, auto-fix: false]
 whitespace: Tool for detection of leading and trailing whitespace [fast: true, auto-fix: true]
+wsl: Whitespace Linter - Forces you to use empty lines! [fast: true, auto-fix: false]
 ```
 
 Pass `-E/--enable` to enable linter and `-D/--disable` to disable:
@@ -466,6 +467,7 @@ golangci-lint help linters
 - [godox](https://github.com/matoous/godox) - Tool for detection of FIXME, TODO and other comment keywords
 - [funlen](https://github.com/ultraware/funlen) - Tool for detection of long functions
 - [whitespace](https://github.com/ultraware/whitespace) - Tool for detection of leading and trailing whitespace
+- [wsl](https://github.com/bombsimon/wsl) - Whitespace Linter - Forces you to use empty lines!
 
 ## Configuration
 
@@ -1117,6 +1119,7 @@ Thanks to developers and authors of used linters:
 - [leighmcculloch](https://github.com/leighmcculloch)
 - [matoous](https://github.com/matoous)
 - [ultraware](https://github.com/ultraware)
+- [bombsimon](https://github.com/bombsimon)
 
 ## Changelog
 

go.mod

@@ -4,6 +4,7 @@ go 1.12
 
 require (
 	github.com/OpenPeeDeeP/depguard v1.0.1
+	github.com/bombsimon/wsl v1.0.1
 	github.com/fatih/color v1.7.0
 	github.com/go-critic/go-critic v0.3.5-0.20190904082202-d79a9f0c64db
 	github.com/go-lintpack/lintpack v0.5.2
@@ -39,7 +40,7 @@ require (
 	github.com/ultraware/whitespace v0.0.3
 	github.com/valyala/quicktemplate v1.2.0
 	golang.org/x/tools v0.0.0-20190912215617-3720d1ec3678
-	gopkg.in/yaml.v2 v2.2.2
+	gopkg.in/yaml.v2 v2.2.4
 	honnef.co/go/tools v0.0.1-2019.2.3
 	mvdan.cc/interfacer v0.0.0-20180901003855-c20040233aed
 	mvdan.cc/lint v0.0.0-20170908181259-adc824a0674b // indirect

go.sum

@@ -11,6 +11,8 @@ github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRF
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
+github.com/bombsimon/wsl v1.0.1 h1:GkrpOj7ajds8re6EJXN+k6UtatYSktupigQ2ZfOUIOU=
+github.com/bombsimon/wsl v1.0.1/go.mod h1:DSRwCD8c7NecM11/LnZcTS8nS8OND5ybj04DWM4l8mc=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/coreos/bbolt v1.3.2/go.mod h1:iRUV2dpdMOn7Bo10OQBFzIJO9kkE559Wcmn+qkEiiKk=
@@ -306,6 +308,8 @@ gopkg.in/yaml.v2 v2.0.0-20170812160011-eb3733d160e7/go.mod h1:JAlM8MvJe8wmxCU4Bl
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.4 h1:/eiJrUcujPVeJ3xlSWaiNi3uSVmDGBK1pDHUHAnao1I=
+gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.1-2019.2.3 h1:3JgtbtFHMiCmsznwGVTUWbgGov+pVqnlf1dEJTNAXeM=
 honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=

pkg/golinters/wsl.go

@@ -0,0 +1,63 @@
+package golinters
+
+import (
+	"sync"
+
+	"github.com/bombsimon/wsl"
+	"golang.org/x/tools/go/analysis"
+
+	"github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+	"github.com/golangci/golangci-lint/pkg/lint/linter"
+	"github.com/golangci/golangci-lint/pkg/result"
+)
+
+const (
+	name = "wsl"
+)
+
+// NewWSL returns a new WSL linter.
+func NewWSL() *goanalysis.Linter {
+	var (
+		issues   []result.Issue
+		mu       = sync.Mutex{}
+		analyzer = &analysis.Analyzer{
+			Name: goanalysis.TheOnlyAnalyzerName,
+			Doc:  goanalysis.TheOnlyanalyzerDoc,
+		}
+	)
+
+	return goanalysis.NewLinter(
+		name,
+		"Whitespace Linter - Forces you to use empty lines!",
+		[]*analysis.Analyzer{analyzer},
+		nil,
+	).WithContextSetter(func(lintCtx *linter.Context) {
+		analyzer.Run = func(pass *analysis.Pass) (interface{}, error) {
+			files := []string{}
+
+			for _, file := range pass.Files {
+				files = append(files, pass.Fset.Position(file.Pos()).Filename)
+			}
+
+			wslErrors, _ := wsl.ProcessFiles(files)
+			if len(wslErrors) == 0 {
+				return nil, nil
+			}
+
+			mu.Lock()
+			defer mu.Unlock()
+
+			for _, err := range wslErrors {
+				issues = append(issues, result.Issue{
+					FromLinter: name,
+					Pos:        err.Position,
+					Text:       err.Reason,
+				})
+			}
+
+			return nil, nil
+		}
+	}).WithIssuesReporter(func(*linter.Context) []result.Issue {
+		return issues
+	}).WithLoadMode(goanalysis.LoadModeSyntax)
+}

pkg/lint/lintersdb/manager.go

@@ -201,6 +201,9 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithPresets(linter.PresetStyle).
 			WithAutoFix().
 			WithURL("https://github.com/ultraware/whitespace"),
+		linter.NewConfig(golinters.NewWSL()).
+			WithPresets(linter.PresetStyle).
+			WithURL("https://github.com/bombsimon/wsl"),
 	}
 
 	isLocalRun := os.Getenv("GOLANGCI_COM_RUN") == ""

test/testdata/wsl.go

@@ -0,0 +1,80 @@
+//args: -Ewsl
+//config: linters-settings.wsl.tests=1
+package testdata
+
+import (
+	"context"
+	"fmt"
+)
+
+func main() {
+	var (
+		y = 0
+	)
+	if y < 1 { // ERROR "if statements should only be cuddled with assignments"
+		fmt.Println("tight")
+	}
+
+	thisIsNotUsedInIf := true
+	if 2 > 1 { // ERROR "if statements should only be cuddled with assignments used in the if statement itself"
+		return
+	}
+
+	one := 1
+	two := 2
+	three := 3
+	if three == 3 { // ERROR "only one cuddle assignment allowed before if statement"
+		fmt.Println("too many cuddled assignments", one, two, thisIsNotUsedInIf)
+	}
+
+	var a = "a"
+	var b = "b" // ERROR "declarations should never be cuddled"
+
+	if true {
+		return
+	}
+	if false { // ERROR "if statements should only be cuddled with assignments"
+		return
+	}
+
+	for i := range make([]int, 10) {
+		fmt.Println(i)
+		fmt.Println(i + i)
+		continue // ERROR "branch statements should not be cuddled if block has more than two lines"
+	}
+
+	assignOne := a
+	fmt.Println(assignOne)
+	assignTwo := b // ERROR "assignments should only be cuddled with other assignments"
+	fmt.Println(assignTwo)
+
+	_, cf1 := context.WithCancel(context.Background())
+	_, cf2 := context.WithCancel(context.Background())
+	defer cf1() // ERROR "only one cuddle assignment allowed before defer statement"
+	defer cf2()
+}
+
+func f1() int {
+	x := 1
+	return x
+}
+
+func f2() int {
+	x := 1
+	y := 3
+	return x + y // ERROR "return statements should not be cuddled if block has more than two lines"
+}
+
+func f3() int {
+	sum := 0
+	for _, v := range []int{2, 4, 8} {
+		sum += v
+	}
+
+	notSum := 0
+	for _, v := range []int{1, 2, 4} { // ERROR "ranges should only be cuddled with assignments used in the iteration"
+		sum += v
+	}
+
+	return sum + notSum
+}