Fixup clean path uninstall

While uninstalling, we weren't checking if we left any empty dir behind.
Now we walk the full path to the file in the artifact, and check each
subdir if it's empty. If it is, we delete it as it is claimed by the
package

pkg/helpers/match.go

@@ -17,9 +17,18 @@
 package helpers
 
 import (
+	"reflect"
 	"regexp"
 )
 
+func ReverseAny(s interface{}) {
+	n := reflect.ValueOf(s).Len()
+	swap := reflect.Swapper(s)
+	for i, j := 0, n-1; i < j; i, j = i+1, j-1 {
+		swap(i, j)
+	}
+}
+
 func MapMatchRegex(m *map[string]string, r *regexp.Regexp) bool {
 	ans := false
 

pkg/installer/installer.go

@@ -889,6 +889,51 @@ func (l *LuetInstaller) installerWorker(i int, wg *sync.WaitGroup, c <-chan Arti
 	return nil
 }
 
+func checkAndPrunePath(path string) {
+	// check if now the target path is empty
+	targetPath := filepath.Dir(path)
+
+	fi, err := os.Lstat(targetPath)
+	if err != nil {
+		Warning("Dir not found (it was before?) ", err.Error())
+		return
+	}
+
+	switch mode := fi.Mode(); {
+	case mode.IsDir():
+		files, err := ioutil.ReadDir(targetPath)
+		if err != nil {
+			Warning("Failed reading folder", targetPath, err.Error())
+		}
+		if len(files) != 0 {
+			Debug("Preserving not-empty folder", targetPath)
+			return
+		}
+	}
+	if err = os.Remove(targetPath); err != nil {
+		Warning("Failed removing file (maybe not present in the system target anymore ?)", targetPath, err.Error())
+	}
+}
+
+// We will try to cleanup every path from the file, if the folders left behind are empty
+func pruneEmptyFilePath(path string) {
+	checkAndPrunePath(path)
+
+	// A path is for e.g. /usr/bin/bar
+	// we want to create an array as "/usr", "/usr/bin", "/usr/bin/bar"
+	paths := strings.Split(path, string(os.PathSeparator))
+	currentPath := filepath.Join(string(os.PathSeparator), paths[0])
+	allPaths := []string{currentPath}
+	for _, p := range paths[1:] {
+		currentPath = filepath.Join(currentPath, p)
+		allPaths = append(allPaths, currentPath)
+	}
+	helpers.ReverseAny(allPaths)
+	for _, p := range allPaths {
+		checkAndPrunePath(p)
+	}
+}
+
 func (l *LuetInstaller) uninstall(p pkg.Package, s *System) error {
 	var cp *config.ConfigProtect
 	annotationDir := ""
@@ -950,6 +995,8 @@ func (l *LuetInstaller) uninstall(p pkg.Package, s *System) error {
 		if err = os.Remove(target); err != nil {
 			Warning("Failed removing file (maybe not present in the system target anymore ?)", target, err.Error())
 		}
+
+		pruneEmptyFilePath(target)
 	}
 
 	for _, f := range notPresent {
@@ -963,6 +1010,8 @@ func (l *LuetInstaller) uninstall(p pkg.Package, s *System) error {
 		if err = os.Remove(target); err != nil {
 			Debug("Failed removing file (not present in the system target)", target, err.Error())
 		}
+
+		pruneEmptyFilePath(target)
 	}
 
 	err = s.Database.RemovePackageFiles(p)