Switch to a for loop.

Author: dlorenc

differs/pip_diff.go

@@ -17,8 +17,8 @@ limitations under the License.
 package differs
 
 import (
+	"errors"
 	"io/ioutil"
-	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -124,34 +124,26 @@ func addToMap(packages map[string]map[string]util.PackageInfo, pack string, path
 
 func getPythonVersion(pathToLayer string) ([]string, error) {
 	matches := []string{}
+	pattern := regexp.MustCompile("^python[0-9]+\\.[0-9]+$")
 
-	// Debian based distros
-	libPath := filepath.Join(pathToLayer, "usr/local/lib")
-	libContents, err := ioutil.ReadDir(libPath)
-	if err != nil {
-		logrus.Warnf("Could not find /usr/local/lib to determine Python version, trying /usr/lib: %s", err)
-		libContents = []os.FileInfo{}
-	}
-
-	// Fedora, CentOS, RHEL, ...
-	libPath = filepath.Join(pathToLayer, "usr/lib")
-	libContents2, err2 := ioutil.ReadDir(libPath)
-	if err2 != nil {
+	libPaths := []string{"usr/local/lib", "usr/lib"}
+	for _, lp := range libPaths {
+		libPath := filepath.Join(pathToLayer, lp)
+		libContents, err := ioutil.ReadDir(libPath)
 		if err != nil {
-			logrus.Errorf("Could not find /usr/lib nor /usr/local/lib to determine Python version: %s", err2)
-			return matches, err
+			logrus.Debugf("Could not find %s to determine Python version", err)
+			continue
 		}
-		logrus.Warnf("Could not find /usr/lib to determine Python version, using /usr/local/lib: %s", err2)
-		libContents2 = []os.FileInfo{}
-	}
-
-	for _, file := range append(libContents, libContents2...) {
-		pattern := regexp.MustCompile("^python[0-9]+\\.[0-9]+$")
-		match := pattern.FindString(file.Name())
-		if match != "" {
-			matches = append(matches, match)
+		for _, file := range libContents {
+			match := pattern.FindString(file.Name())
+			if match != "" {
+				matches = append(matches, match)
+			}
 		}
 	}
+	if len(matches) == 0 {
+		return nil, errors.New("unable to determine Python version")
+	}
 	return matches, nil
 }