Improved error messages

Author: nao1215

Changelog.md

@@ -5,6 +5,7 @@ All notable changes to this project will be documented in this file. The format
 ## Changed
 - Parallelized update process
 - Simplified messages during the update process
+- Improved error messages
 # [0.9.1] - 2022-03-19
 ## Changed 
 - Changed the message at the time of update was incorrect, so the message was corrected.

cmd/update.go

@@ -83,10 +83,10 @@ func update(pkgs []goutil.Package, dryRun bool) int {
 	updater := func(p goutil.Package, result chan updateResult) {
 		var err error
 		if p.ImportPath == "" {
-			err = fmt.Errorf(" %s", p.Name)
+			err = fmt.Errorf(" %s is not installed by 'go install' (or permission incorrect)", p.Name)
 		} else {
 			if err = goutil.Install(p.ImportPath); err != nil {
-				err = fmt.Errorf(" %w: %s", err, p.Name)
+				err = fmt.Errorf(" %s %w", p.Name, err)
 			}
 		}
 

internal/goutil/goutil.go

@@ -151,10 +151,10 @@ func CanUseGoCmd() error {
 // Install execute "$ go install <importPath>@latest"
 func Install(importPath string) error {
 	if importPath == "command-line-arguments" {
-		return errors.New("this is devel-binary copied from local environment")
+		return errors.New("is devel-binary copied from local environment")
 	}
 	if err := exec.Command("go", "install", importPath+"@latest").Run(); err != nil {
-		return errors.New("can't install " + importPath)
+		return fmt.Errorf("can't install %s: %w", importPath, err)
 	}
 	return nil
 }