Move get file extension logic to util

copy.go

@@ -37,7 +37,7 @@ func copySize(srcs []string) (int64, error) {
 }
 
 func copyFile(src, dst string, preserve []string, info os.FileInfo, nums chan int64) error {
-	var dst_mode os.FileMode = 0666
+	var dst_mode os.FileMode = 0o666
 	preserve_timestamps := false
 	for _, s := range preserve {
 		switch s {
@@ -107,9 +107,9 @@ func copyAll(srcs []string, dstDir string, preserve []string) (nums chan int64,
 			file := filepath.Base(src)
 			dst := filepath.Join(dstDir, file)
 
-			_, err := os.Lstat(dst)
+			lstat, err := os.Lstat(dst)
 			if !os.IsNotExist(err) {
-				ext := filepath.Ext(file)
+				ext := getFileExtension(lstat)
 				basename := file[:len(file)-len(ext)]
 				var newPath string
 				for i := 1; !os.IsNotExist(err); i++ {

eval.go

@@ -1611,8 +1611,8 @@ func (e *callExpr) eval(app *app, args []string) {
 			}
 			normal(app)
 			app.ui.cmdPrefix = "rename: "
-			extension := filepath.Ext(curr.Name())
-			if len(extension) == 0 || extension == curr.Name() || curr.IsDir() {
+			extension := getFileExtension(curr)
+			if extension == "" {
 				// no extension or .hidden or is directory
 				app.ui.cmdAccLeft = append(app.ui.cmdAccLeft, []rune(curr.Name())...)
 			} else {

misc.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"fmt"
 	"io"
+	"io/fs"
 	"path/filepath"
 	"regexp"
 	"strconv"
@@ -291,12 +292,31 @@ func naturalLess(s1, s2 string) bool {
 	}
 }
 
-var reModKey = regexp.MustCompile(`<(c|s|a)-(.+)>`)
-var reRulerSub = regexp.MustCompile(`%[apmcsfithd]|%\{[^}]+\}`)
+// This function returns the extension of a file with a leading dot
+// it returns an empty string if extension could not be determined
+// i.e. directories, filenames without extensions
+func getFileExtension(file fs.FileInfo) string {
+	if file.IsDir() {
+		return ""
+	}
+	extension := filepath.Ext(file.Name())
+	if strings.Count(file.Name(), ".") == 1 && file.Name()[0] == '.' {
+		// hidden file without extension
+		return ""
+	}
+	return extension
+}
 
-var reWord = regexp.MustCompile(`(\pL|\pN)+`)
-var reWordBeg = regexp.MustCompile(`([^\pL\pN]|^)(\pL|\pN)`)
-var reWordEnd = regexp.MustCompile(`(\pL|\pN)([^\pL\pN]|$)`)
+var (
+	reModKey   = regexp.MustCompile(`<(c|s|a)-(.+)>`)
+	reRulerSub = regexp.MustCompile(`%[apmcsfithd]|%\{[^}]+\}`)
+)
+
+var (
+	reWord    = regexp.MustCompile(`(\pL|\pN)+`)
+	reWordBeg = regexp.MustCompile(`([^\pL\pN]|^)(\pL|\pN)`)
+	reWordEnd = regexp.MustCompile(`(\pL|\pN)([^\pL\pN]|$)`)
+)
 
 func min(a, b int) int {
 	if a < b {

misc_test.go

@@ -293,3 +293,49 @@ func TestNaturalLess(t *testing.T) {
 		}
 	}
 }
+
+func TestGetFileExtension(t *testing.T) {
+	tests := []struct {
+		name              string
+		fileName          string
+		expectedExtension string
+	}{
+		{"normal file", "file.txt", ".txt"},
+		{"file without extension", "file", ""},
+		{"hidden file", ".gitignore", ""},
+		{"hidden file with extension", ".file.txt", ".txt"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			dir := t.TempDir()
+			file, err := os.Create(dir + "/" + test.fileName)
+			if err != nil {
+				t.Fatalf("failed to create file: %v", err)
+			}
+
+			fileInfo, err := file.Stat()
+			if err != nil {
+				t.Fatalf("failed to get file info: %v", err)
+			}
+
+			if got := getFileExtension(fileInfo); got != test.expectedExtension {
+				t.Errorf("at input %q expected %q but got %q", test.fileName, test.expectedExtension, got)
+			}
+		})
+	}
+
+	t.Run("directory", func(t *testing.T) {
+		dir := t.TempDir()
+
+		fileInfo, err := os.Stat(dir)
+		if err != nil {
+			t.Fatalf("failed to get file info: %v", err)
+		}
+
+		expectedExtension := ""
+		if got := getFileExtension(fileInfo); got != expectedExtension {
+			t.Errorf("at input %q expected %q but got %q", dir, expectedExtension, got)
+		}
+	})
+}

nav.go

@@ -55,7 +55,7 @@ type fakeStat struct {
 
 func (fs *fakeStat) Name() string       { return fs.name }
 func (fs *fakeStat) Size() int64        { return 0 }
-func (fs *fakeStat) Mode() os.FileMode  { return os.FileMode(0000) }
+func (fs *fakeStat) Mode() os.FileMode  { return os.FileMode(0o000) }
 func (fs *fakeStat) ModTime() time.Time { return time.Unix(0, 0) }
 func (fs *fakeStat) IsDir() bool        { return false }
 func (fs *fakeStat) Sys() any           { return nil }
@@ -88,7 +88,7 @@ func readdir(path string) ([]*file, error) {
 				dirSize:    -1,
 				accessTime: time.Unix(0, 0),
 				changeTime: time.Unix(0, 0),
-				ext:        filepath.Ext(fpath),
+				ext:        getFileExtension(lstat),
 				err:        err,
 			})
 			continue
@@ -122,10 +122,6 @@ func readdir(path string) ([]*file, error) {
 			ct = lstat.ModTime()
 		}
 
-		// returns an empty string if extension could not be determined
-		// i.e. directories, filenames without extensions
-		ext := filepath.Ext(fpath)
-
 		dirCount := -1
 		if lstat.IsDir() && gOpts.dircounts {
 			d, err := os.Open(fpath)
@@ -152,7 +148,7 @@ func readdir(path string) ([]*file, error) {
 			dirSize:    -1,
 			accessTime: at,
 			changeTime: ct,
-			ext:        ext,
+			ext:        getFileExtension(lstat),
 			err:        nil,
 		})
 	}
@@ -492,7 +488,6 @@ func (nav *nav) loadDirInternal(path string) *dir {
 			nav.dirPreviewChan <- d
 		}
 		nav.dirChan <- d
-
 	}()
 	return d
 }
@@ -773,7 +768,6 @@ func matchPattern(pattern, name, path string) bool {
 }
 
 func (nav *nav) previewDir(dir *dir, win *win) {
-
 	defer func() {
 		dir.loading = false
 		nav.dirChan <- dir
@@ -829,11 +823,9 @@ func (nav *nav) previewDir(dir *dir, win *win) {
 			log.Printf("loading dir: %s", buf.Err())
 		}
 	}
-
 }
 
 func (nav *nav) preview(path string, win *win) {
-
 	reg := &reg{loadTime: time.Now(), path: path}
 	defer func() { nav.regChan <- reg }()
 
@@ -1408,7 +1400,7 @@ func (nav *nav) moveAsync(app *app, srcs []string, dstDir string) {
 			app.ui.exprChan <- echo
 			continue
 		} else if !os.IsNotExist(err) {
-			ext := filepath.Ext(file)
+			ext := getFileExtension(dstStat)
 			basename := file[:len(file)-len(ext)]
 			var newPath string
 			for i := 1; !os.IsNotExist(err); i++ {
@@ -1991,7 +1983,6 @@ func (m indexedSelections) Swap(i, j int) {
 func (m indexedSelections) Less(i, j int) bool { return m.indices[i] < m.indices[j] }
 
 func (nav *nav) currSelections() []string {
-
 	currDirOnly := gOpts.selmode == "dir"
 	currDirPath := ""
 	if currDirOnly {