Support editorconfig

_fixtures/editorconfig_max_len.go

@@ -0,0 +1,20 @@
+package fixtures
+
+import (
+	"fmt"
+	"time"
+)
+
+func _() {
+	veryLongString := fmt.Sprintf("The current time is %v and %d, %d, %d, %d, %d, %d", time.Now(), 1, 2, 3, 4, 5, 6)
+	anotherLongString := fmt.Sprintf("The current time is %v and %d, %d, %d, %d, %d, %d, %d, %d, %d", time.Now(), 1, 2, 3, 4, 5, 6, 7, 8, 9)
+
+	extremelyLongSlice := []string{"This is the first very long element in a slice", "This is the second very long element that contains a lot of text to make the line exceed 120 characters", "And this is the third one"}
+
+	someVeryLongMap := map[string]string{"ThisIsAVeryLongKeyThatWillMakeThisLineExceed120Characters": "AndThisIsAnEquallyLongValueThatWillContributeToMakingThisLineVeryVeryLongIndeed"}
+
+	_ = veryLongString
+	_ = anotherLongString
+	_ = extremelyLongSlice
+	_ = someVeryLongMap
+}

_fixtures/editorconfig_max_len__exp.go

@@ -0,0 +1,38 @@
+package fixtures
+
+import (
+	"fmt"
+	"time"
+)
+
+func _() {
+	veryLongString := fmt.Sprintf("The current time is %v and %d, %d, %d, %d, %d, %d", time.Now(), 1, 2, 3, 4, 5, 6)
+	anotherLongString := fmt.Sprintf(
+		"The current time is %v and %d, %d, %d, %d, %d, %d, %d, %d, %d",
+		time.Now(),
+		1,
+		2,
+		3,
+		4,
+		5,
+		6,
+		7,
+		8,
+		9,
+	)
+
+	extremelyLongSlice := []string{
+		"This is the first very long element in a slice",
+		"This is the second very long element that contains a lot of text to make the line exceed 120 characters",
+		"And this is the third one",
+	}
+
+	someVeryLongMap := map[string]string{
+		"ThisIsAVeryLongKeyThatWillMakeThisLineExceed120Characters": "AndThisIsAnEquallyLongValueThatWillContributeToMakingThisLineVeryVeryLongIndeed",
+	}
+
+	_ = veryLongString
+	_ = anotherLongString
+	_ = extremelyLongSlice
+	_ = someVeryLongMap
+}

go.mod

@@ -1,10 +1,13 @@
 module github.com/segmentio/golines
 
-go 1.21
+go 1.22.0
+
+toolchain go1.24.2
 
 require (
 	github.com/dave/dst v0.27.3
 	github.com/dave/jennifer v1.7.0
+	github.com/editorconfig/editorconfig-core-go/v2 v2.6.3
 	github.com/fatih/structtag v1.2.0
 	github.com/pmezard/go-difflib v1.0.0
 	github.com/sirupsen/logrus v1.9.3
@@ -24,9 +27,10 @@ require (
 	github.com/onsi/ginkgo v1.10.2 // indirect
 	github.com/onsi/gomega v1.7.0 // indirect
 	golang.org/x/crypto v0.31.0 // indirect
-	golang.org/x/mod v0.14.0 // indirect
+	golang.org/x/mod v0.23.0 // indirect
 	golang.org/x/sys v0.28.0 // indirect
 	golang.org/x/tools v0.17.0 // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -9,10 +9,14 @@ github.com/dave/jennifer v1.7.0/go.mod h1:nXbxhEmQfOZhWml3D1cDK5M1FLnMSozpbFN/m3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/editorconfig/editorconfig-core-go/v2 v2.6.3 h1:XVUp6qW3BIkmM3/1EkrHpa6bL56APOynfXcZEmIgOhs=
+github.com/editorconfig/editorconfig-core-go/v2 v2.6.3/go.mod h1:ThHVc+hqbUsmE1wmK/MASpQEhCleWu1JDJDNhUOMy0c=
 github.com/fatih/structtag v1.2.0 h1:/OdNE99OxoI/PqaW/SuSK9uxxT3f/tcSZgon/ssNSx4=
 github.com/fatih/structtag v1.2.0/go.mod h1:mBJUNpUnHmRKrKlQQlmCrh5PuhftFbNv8Ys4/aAZl94=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
+github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
@@ -42,8 +46,8 @@ github.com/x-cray/logrus-prefixed-formatter v0.5.2 h1:00txxvfBM9muc0jiLIEAkAcIMJ
 github.com/x-cray/logrus-prefixed-formatter v0.5.2/go.mod h1:2duySbKsL6M18s5GU7VPsoEPHyzalCE06qoARUCeBBE=
 golang.org/x/crypto v0.31.0 h1:ihbySMvVjLAeSH1IbfcRTkD/iNscyz8rGzjF/E5hV6U=
 golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
-golang.org/x/mod v0.14.0 h1:dGoOF9QVLYng8IHTm7BAyWqCqSheQ5pYWGhzW00YJr0=
-golang.org/x/mod v0.14.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/mod v0.23.0 h1:Zb7khfcRGKk+kqfxFaP5tZqCnDZMjC5VtUBs87Hr6QM=
+golang.org/x/mod v0.23.0/go.mod h1:6SkKJ3Xj0I0BrPOZoBy3bdMptDDU9oJrpohJ3eWZ1fY=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
 golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
@@ -69,6 +73,8 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/fsnotify.v1 v1.4.7 h1:xOHLXZwVvI9hhs+cLKq5+I5onOuwQLhQwiu63xxlHs4=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
+gopkg.in/ini.v1 v1.67.0 h1:Dgnx+6+nfE+IfzjUEISNeydPJh9AXNNsWbGP9KzCsOA=
+gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 h1:uRGJdciOHaEIrze2W8Q3AKkepLTh2hOroT7a+7czfdQ=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

main.go

@@ -15,6 +15,8 @@ import (
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 
+const defaultMaxLen = 100
+
 var (
 	// these values are provided automatically by Goreleaser
 	//   ref: https://goreleaser.com/customization/builds/
@@ -53,7 +55,7 @@ var (
 		"List files that would be reformatted by this tool").Short('l').Default("false").Bool()
 	maxLen = kingpin.Flag(
 		"max-len",
-		"Target maximum line length").Short('m').Default("100").Int()
+		fmt.Sprintf("Maximum line length, or .editorconfig or default to %d", defaultMaxLen)).Short('m').Int()
 	profile = kingpin.Flag(
 		"profile",
 		"Path to profile output").Default("").String()
@@ -118,6 +120,7 @@ func main() {
 func run() error {
 	config := ShortenerConfig{
 		MaxLen:           *maxLen,
+		CurrentMaxLen:    0,
 		TabLen:           *tabLen,
 		KeepAnnotations:  *keepAnnotations,
 		ShortenComments:  *shortenComments,
@@ -127,6 +130,7 @@ func run() error {
 		BaseFormatterCmd: *baseFormatterCmd,
 		ChainSplitDots:   *chainSplitDots,
 	}
+
 	shortener := NewShortener(config)
 
 	if len(*paths) == 0 {
@@ -219,7 +223,9 @@ func processFile(shortener *Shortener, path string) ([]byte, []byte, error) {
 		return nil, nil, err
 	}
 
+	shortener.SetCurrentMaxLen(path)
 	result, err := shortener.Shorten(contents)
+
 	return contents, result, err
 }
 
@@ -258,5 +264,4 @@ func handleOutput(path string, contents []byte, result []byte) error {
 
 	fmt.Print(string(result))
 	return nil
-
 }

shortener.go

@@ -10,10 +10,12 @@ import (
 	"os/exec"
 	"reflect"
 	"regexp"
+	"strconv"
 	"strings"
 
 	"github.com/dave/dst"
 	"github.com/dave/dst/decorator"
+	editorconfig "github.com/editorconfig/editorconfig-core-go/v2"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -36,6 +38,7 @@ const maxRounds = 20
 // ShortenerConfig stores the configuration options exposed by a Shortener instance.
 type ShortenerConfig struct {
 	MaxLen          int    // Max target width for each line
+	CurrentMaxLen   int    // Max target width for each line for the current file or context
 	TabLen          int    // Width of a tab character
 	KeepAnnotations bool   // Whether to keep annotations in final result (for debugging only)
 	ShortenComments bool   // Whether to shorten comments
@@ -86,9 +89,43 @@ func NewShortener(config ShortenerConfig) *Shortener {
 		s.baseFormatterArgs = []string{}
 	}
 
+	s.config.CurrentMaxLen = s.config.MaxLen
+	if s.config.CurrentMaxLen == 0 {
+		s.config.CurrentMaxLen = defaultMaxLen
+	}
+
 	return s
 }
 
+func (s *Shortener) SetCurrentMaxLen(path string) {
+	// defined by user
+	if s.config.MaxLen != 0 {
+		s.config.CurrentMaxLen = s.config.MaxLen
+
+		return
+	}
+
+	// Try to get .editorconfig definition for the given path
+	def, err := editorconfig.GetDefinitionForFilename(path)
+	if err != nil {
+		s.config.CurrentMaxLen = defaultMaxLen
+
+		return
+	}
+
+	defMaxLen, ok := def.Raw["max_line_length"]
+	if ok && defMaxLen != editorconfig.UnsetValue {
+		defMaxLenInt, err := strconv.Atoi(defMaxLen)
+		if err == nil {
+			s.config.CurrentMaxLen = defMaxLenInt
+
+			return
+		}
+	}
+
+	s.config.CurrentMaxLen = defaultMaxLen
+}
+
 // Shorten shortens the provided golang file content bytes.
 func (s *Shortener) Shorten(contents []byte) ([]byte, error) {
 	if s.config.IgnoreGenerated && s.isGenerated(contents) {
@@ -101,7 +138,7 @@ func (s *Shortener) Shorten(contents []byte) ([]byte, error) {
 	// Do initial, non-line-length-aware formatting
 	contents, err = s.formatSrc(contents)
 	if err != nil {
-		return nil, fmt.Errorf("Error formatting source: %+v", err)
+		return nil, fmt.Errorf("error formatting source: %+v", err)
 	}
 
 	for {
@@ -234,15 +271,15 @@ func (s *Shortener) annotateLongLines(lines []string) ([]string, int) {
 		length := s.lineLen(line)
 
 		if prevLen > -1 {
-			if length <= s.config.MaxLen {
+			if length <= s.config.CurrentMaxLen {
 				// Shortening successful, remove previous annotation
 				annotatedLines = annotatedLines[:len(annotatedLines)-1]
 			} else if length < prevLen {
 				// Replace annotation with new length
 				annotatedLines[len(annotatedLines)-1] = CreateAnnotation(length)
 				linesToShorten++
 			}
-		} else if !s.isComment(line) && length > s.config.MaxLen {
+		} else if !s.isComment(line) && length > s.config.CurrentMaxLen {
 			annotatedLines = append(
 				annotatedLines,
 				CreateAnnotation(length),
@@ -282,7 +319,7 @@ func (s *Shortener) shortenCommentsFunc(contents []byte) []byte {
 	for _, line := range lines {
 		if s.isComment(line) && !IsAnnotation(line) &&
 			!s.isGoDirective(line) &&
-			s.lineLen(line) > s.config.MaxLen {
+			s.lineLen(line) > s.config.CurrentMaxLen {
 			start := strings.Index(line, "//")
 			prefix = line[0:(start + 2)]
 			trimmedLine := strings.Trim(line[(start+2):], " ")
@@ -292,7 +329,7 @@ func (s *Shortener) shortenCommentsFunc(contents []byte) []byte {
 			// Reflow the accumulated `words` before appending the unprocessed `line`.
 			currLineLen := 0
 			currLineWords := []string{}
-			maxCommentLen := s.config.MaxLen - s.lineLen(prefix)
+			maxCommentLen := s.config.CurrentMaxLen - s.lineLen(prefix)
 			for _, word := range words {
 				if currLineLen > 0 && currLineLen+1+len(word) > maxCommentLen {
 					cleanedLines = append(