chore: fix linter errors (#634)

Signed-off-by: Ravi Chamarthy <[email protected]>

pkg/container/container.go

@@ -116,9 +116,9 @@ func (c *Container) containerError(theErr error, msg string) error {
 	}
 
 	for _, err := range lxcErrors {
-		log.Debugf(err)
+		log.Debugf("%s", err)
 	}
-	return errors.Wrapf(theErr, msg)
+	return errors.Wrap(theErr, msg)
 }
 
 func (c *Container) Execute(args []string, stdin io.Reader) error {

pkg/log/log.go

@@ -75,7 +75,7 @@ func (th *TextHandler) HandleLog(e *log.Entry) error {
 		}
 	}
 
-	_, err := th.out.WriteString(fmt.Sprintf(e.Message))
+	_, err := th.out.WriteString(e.Message)
 	if err != nil {
 		return err
 	}

pkg/squashfs/squashfs.go

@@ -625,7 +625,7 @@ func ExtractSingleSquashPolicy(squashFile, extractDir string, policy *ExtractPol
 		policy.Excuses = map[string]error{}
 	}
 
-	if policy.Extractors == nil || len(policy.Extractors) == 0 {
+	if len(policy.Extractors) == 0 {
 		policy.Excuses[initName] = errors.Errorf("policy had no extractors")
 		return policy.Excuses[initName]
 	}
@@ -647,7 +647,7 @@ func ExtractSingleSquashPolicy(squashFile, extractDir string, policy *ExtractPol
 	}
 
 	// nothing worked. populate Excuses[initName]
-	policy.Excuses[initName] = errors.Errorf("No suitable extractor found:\n  " + strings.Join(allExcuses, "\n  "))
+	policy.Excuses[initName] = errors.Errorf("No suitable extractor found:\n %s", strings.Join(allExcuses, "\n  "))
 	return policy.Excuses[initName]
 }
 

pkg/types/layer_type.go

@@ -19,7 +19,7 @@ type LayerType struct {
 
 func (lt LayerType) String() string {
 	if lt.Verity {
-		return fmt.Sprintf(lt.Type + "+verity")
+		return fmt.Sprintf("%s+verity", lt.Type)
 	}
 	return lt.Type
 }

pkg/types/stackerfile.go

@@ -123,7 +123,7 @@ func substitute(content string, substitutions []string) (string, error) {
 
 	if len(unsupported_messages) > 0 {
 		for _, msg := range unsupported_messages {
-			log.Errorf(msg)
+			log.Errorf("%s", msg)
 		}
 		return "", errors.Errorf("%d instances of unsupported placeholders found. Review log for how to update.", len(unsupported_messages))
 	}