treat \ as escape only before a separator

mapper.go

@@ -721,12 +721,15 @@ func SplitEscaped(s string, sep rune) (out []string) {
 	}
 	escaped := false
 	token := ""
-	for _, ch := range s {
+	for i, ch := range s {
 		switch {
 		case escaped:
+			if ch != sep {
+				token += `\`
+			}
 			token += string(ch)
 			escaped = false
-		case ch == '\\':
+		case ch == '\\' && i < len(s)-1:
 			escaped = true
 		case ch == sep && !escaped:
 			out = append(out, token)

mapper_linux_test.go

@@ -0,0 +1,26 @@
+//go:build !windows
+// +build !windows
+
+package kong_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPathMapper(t *testing.T) {
+	var cli struct {
+		Path string `arg:"" type:"path"`
+	}
+	p := mustNew(t, &cli)
+
+	_, err := p.Parse([]string{"/an/absolute/path"})
+	require.NoError(t, err)
+	require.Equal(t, "/an/absolute/path", cli.Path)
+
+	_, err = p.Parse([]string{"-"})
+	require.NoError(t, err)
+	require.Equal(t, "-", cli.Path)
+}

mapper_test.go

@@ -9,6 +9,7 @@ import (
 	"net/url"
 	"os"
 	"reflect"
+	"runtime"
 	"strings"
 	"testing"
 	"time"
@@ -412,27 +413,16 @@ func TestFileMapper(t *testing.T) {
 	_ = cli.File.Close()
 	_, err = p.Parse([]string{"testdata/missing.txt"})
 	require.Error(t, err)
-	require.Contains(t, err.Error(), "missing.txt: no such file or directory")
+	if runtime.GOOS == "windows" {
+		require.Contains(t, err.Error(), "missing.txt: The system cannot find the file specified.")
+	} else {
+		require.Contains(t, err.Error(), "missing.txt: no such file or directory")
+	}
 	_, err = p.Parse([]string{"-"})
 	require.NoError(t, err)
 	require.Equal(t, os.Stdin, cli.File)
 }
 
-func TestPathMapper(t *testing.T) {
-	var cli struct {
-		Path string `arg:"" type:"path"`
-	}
-	p := mustNew(t, &cli)
-
-	_, err := p.Parse([]string{"/an/absolute/path"})
-	require.NoError(t, err)
-	require.Equal(t, "/an/absolute/path", cli.Path)
-
-	_, err = p.Parse([]string{"-"})
-	require.NoError(t, err)
-	require.Equal(t, "-", cli.Path)
-}
-
 func TestMapperPlaceHolder(t *testing.T) {
 	var cli struct {
 		Flag string

mapper_windows_test.go

@@ -0,0 +1,44 @@
+//go:build windows
+// +build windows
+
+package kong_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestWindowsPathMapper(t *testing.T) {
+	var cli struct {
+		Path  string   `short:"p" type:"path"`
+		Files []string `short:"f" type:"path"`
+	}
+	wd, err := os.Getwd()
+	require.NoError(t, err, "Getwd failed")
+	p := mustNew(t, &cli)
+
+	_, err = p.Parse([]string{`-p`, `c:\an\absolute\path`, `-f`, `c:\second\absolute\path\`, `-f`, `relative\path\file`})
+	require.NoError(t, err)
+	require.Equal(t, `c:\an\absolute\path`, cli.Path)
+	require.Equal(t, []string{`c:\second\absolute\path\`, wd + `\relative\path\file`}, cli.Files)
+}
+
+func TestWindowsFileMapper(t *testing.T) {
+	type CLI struct {
+		File *os.File `arg:""`
+	}
+	var cli CLI
+	p := mustNew(t, &cli)
+	_, err := p.Parse([]string{"testdata\\file.txt"})
+	require.NoError(t, err)
+	require.NotNil(t, cli.File)
+	_ = cli.File.Close()
+	_, err = p.Parse([]string{"testdata\\missing.txt"})
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "missing.txt: The system cannot find the file specified.")
+	_, err = p.Parse([]string{"-"})
+	require.NoError(t, err)
+	require.Equal(t, os.Stdin, cli.File)
+}

util_test.go

@@ -4,6 +4,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 
@@ -62,7 +63,9 @@ func TestChangeDirFlag(t *testing.T) {
 	p := Must(&cli)
 	_, err = p.Parse([]string{"-C", dir, "out.txt"})
 	require.NoError(t, err)
-	file, err = filepath.EvalSymlinks(file) // Needed because OSX uses a symlinked tmp dir.
-	require.NoError(t, err)
+	if runtime.GOOS != "windows" {
+		file, err = filepath.EvalSymlinks(file) // Needed because OSX uses a symlinked tmp dir.
+		require.NoError(t, err)
+	}
 	require.Equal(t, file, cli.Path)
 }