add 'CheckErr' and 'assertNoErr'

README.md

@@ -234,21 +234,14 @@ func init() {
 	rootCmd.AddCommand(initCmd)
 }
 
-func er(msg interface{}) {
-	fmt.Println("Error:", msg)
-	os.Exit(1)
-}
-
 func initConfig() {
 	if cfgFile != "" {
 		// Use config file from the flag.
 		viper.SetConfigFile(cfgFile)
 	} else {
 		// Find home directory.
 		home, err := homedir.Dir()
-		if err != nil {
-			er(err)
-		}
+		cobra.CheckErr(err)
 
 		// Search config in home directory with name ".cobra" (without extension).
 		viper.AddConfigPath(home)

bash_completions_test.go

@@ -51,7 +51,9 @@ func runShellCheck(s string) error {
 		return err
 	}
 	go func() {
-		stdin.Write([]byte(s))
+		_, err := stdin.Write([]byte(s))
+		CheckErr(err)
+
 		stdin.Close()
 	}()
 
@@ -73,26 +75,26 @@ func TestBashCompletions(t *testing.T) {
 		Run:                    emptyRun,
 	}
 	rootCmd.Flags().IntP("introot", "i", -1, "help message for flag introot")
-	rootCmd.MarkFlagRequired("introot")
+	assertNoErr(t, rootCmd.MarkFlagRequired("introot"))
 
 	// Filename.
 	rootCmd.Flags().String("filename", "", "Enter a filename")
-	rootCmd.MarkFlagFilename("filename", "json", "yaml", "yml")
+	assertNoErr(t, rootCmd.MarkFlagFilename("filename", "json", "yaml", "yml"))
 
 	// Persistent filename.
 	rootCmd.PersistentFlags().String("persistent-filename", "", "Enter a filename")
-	rootCmd.MarkPersistentFlagFilename("persistent-filename")
-	rootCmd.MarkPersistentFlagRequired("persistent-filename")
+	assertNoErr(t, rootCmd.MarkPersistentFlagFilename("persistent-filename"))
+	assertNoErr(t, rootCmd.MarkPersistentFlagRequired("persistent-filename"))
 
 	// Filename extensions.
 	rootCmd.Flags().String("filename-ext", "", "Enter a filename (extension limited)")
-	rootCmd.MarkFlagFilename("filename-ext")
+	assertNoErr(t, rootCmd.MarkFlagFilename("filename-ext"))
 	rootCmd.Flags().String("custom", "", "Enter a filename (extension limited)")
-	rootCmd.MarkFlagCustom("custom", "__complete_custom")
+	assertNoErr(t, rootCmd.MarkFlagCustom("custom", "__complete_custom"))
 
 	// Subdirectories in a given directory.
 	rootCmd.Flags().String("theme", "", "theme to use (located in /themes/THEMENAME/)")
-	rootCmd.Flags().SetAnnotation("theme", BashCompSubdirsInDir, []string{"themes"})
+	assertNoErr(t, rootCmd.Flags().SetAnnotation("theme", BashCompSubdirsInDir, []string{"themes"}))
 
 	// For two word flags check
 	rootCmd.Flags().StringP("two", "t", "", "this is two word flags")
@@ -108,9 +110,9 @@ func TestBashCompletions(t *testing.T) {
 	}
 
 	echoCmd.Flags().String("filename", "", "Enter a filename")
-	echoCmd.MarkFlagFilename("filename", "json", "yaml", "yml")
+	assertNoErr(t, echoCmd.MarkFlagFilename("filename", "json", "yaml", "yml"))
 	echoCmd.Flags().String("config", "", "config to use (located in /config/PROFILE/)")
-	echoCmd.Flags().SetAnnotation("config", BashCompSubdirsInDir, []string{"config"})
+	assertNoErr(t, echoCmd.Flags().SetAnnotation("config", BashCompSubdirsInDir, []string{"config"}))
 
 	printCmd := &Command{
 		Use:   "print [string to print]",
@@ -148,7 +150,7 @@ func TestBashCompletions(t *testing.T) {
 	rootCmd.AddCommand(echoCmd, printCmd, deprecatedCmd, colonCmd)
 
 	buf := new(bytes.Buffer)
-	rootCmd.GenBashCompletion(buf)
+	assertNoErr(t, rootCmd.GenBashCompletion(buf))
 	output := buf.String()
 
 	check(t, output, "_root")
@@ -215,10 +217,10 @@ func TestBashCompletionHiddenFlag(t *testing.T) {
 
 	const flagName = "hiddenFlag"
 	c.Flags().Bool(flagName, false, "")
-	c.Flags().MarkHidden(flagName)
+	assertNoErr(t, c.Flags().MarkHidden(flagName))
 
 	buf := new(bytes.Buffer)
-	c.GenBashCompletion(buf)
+	assertNoErr(t, c.GenBashCompletion(buf))
 	output := buf.String()
 
 	if strings.Contains(output, flagName) {
@@ -231,10 +233,10 @@ func TestBashCompletionDeprecatedFlag(t *testing.T) {
 
 	const flagName = "deprecated-flag"
 	c.Flags().Bool(flagName, false, "")
-	c.Flags().MarkDeprecated(flagName, "use --not-deprecated instead")
+	assertNoErr(t, c.Flags().MarkDeprecated(flagName, "use --not-deprecated instead"))
 
 	buf := new(bytes.Buffer)
-	c.GenBashCompletion(buf)
+	assertNoErr(t, c.GenBashCompletion(buf))
 	output := buf.String()
 
 	if strings.Contains(output, flagName) {
@@ -249,7 +251,7 @@ func TestBashCompletionTraverseChildren(t *testing.T) {
 	c.Flags().BoolP("bool-flag", "b", false, "bool flag")
 
 	buf := new(bytes.Buffer)
-	c.GenBashCompletion(buf)
+	assertNoErr(t, c.GenBashCompletion(buf))
 	output := buf.String()
 
 	// check that local nonpersistent flag are not set since we have TraverseChildren set to true

cobra.go

@@ -19,6 +19,7 @@ package cobra
 import (
 	"fmt"
 	"io"
+	"os"
 	"reflect"
 	"strconv"
 	"strings"
@@ -205,3 +206,11 @@ func stringInSlice(a string, list []string) bool {
 	}
 	return false
 }
+
+// CheckErr prints the msg with the prefix 'Error:' and exits with error code 1. If the msg is nil, it does nothing.
+func CheckErr(msg interface{}) {
+	if msg != nil {
+		fmt.Fprintln(os.Stderr, "Error:", msg)
+		os.Exit(1)
+	}
+}

cobra/cmd/add.go

@@ -40,13 +40,11 @@ Example: cobra add server -> resulting in a new cmd/server.go`,
 
 		Run: func(cmd *cobra.Command, args []string) {
 			if len(args) < 1 {
-				er("add needs a name for the command")
+				cobra.CheckErr(fmt.Errorf("add needs a name for the command"))
 			}
 
 			wd, err := os.Getwd()
-			if err != nil {
-				er(err)
-			}
+			cobra.CheckErr(err)
 
 			commandName := validateCmdName(args[0])
 			command := &Command{
@@ -59,10 +57,7 @@ Example: cobra add server -> resulting in a new cmd/server.go`,
 				},
 			}
 
-			err = command.Create()
-			if err != nil {
-				er(err)
-			}
+			cobra.CheckErr(command.Create())
 
 			fmt.Printf("%s created at %s\n", command.CmdName, command.AbsolutePath)
 		},
@@ -72,7 +67,7 @@ Example: cobra add server -> resulting in a new cmd/server.go`,
 func init() {
 	addCmd.Flags().StringVarP(&packageName, "package", "t", "", "target package name (e.g. github.com/spf13/hugo)")
 	addCmd.Flags().StringVarP(&parentName, "parent", "p", "rootCmd", "variable name of parent command for this command")
-	addCmd.Flags().MarkDeprecated("package", "this operation has been removed.")
+	cobra.CheckErr(addCmd.Flags().MarkDeprecated("package", "this operation has been removed."))
 }
 
 // validateCmdName returns source without any dashes and underscore.

cobra/cmd/add_test.go

@@ -14,10 +14,8 @@ func TestGoldenAddCmd(t *testing.T) {
 	}
 	defer os.RemoveAll(command.AbsolutePath)
 
-	command.Project.Create()
-	if err := command.Create(); err != nil {
-		t.Fatal(err)
-	}
+	assertNoErr(t, command.Project.Create())
+	assertNoErr(t, command.Create())
 
 	generatedFile := fmt.Sprintf("%s/cmd/%s.go", command.AbsolutePath, command.CmdName)
 	goldenFile := fmt.Sprintf("testdata/%s.go.golden", command.CmdName)

cobra/cmd/helpers.go

@@ -14,11 +14,12 @@
 package cmd
 
 import (
-	"fmt"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"
+
+	"github.com/spf13/cobra"
 )
 
 var srcPaths []string
@@ -40,23 +41,16 @@ func init() {
 		}
 
 		out, err := exec.Command(goExecutable, "env", "GOPATH").Output()
-		if err != nil {
-			er(err)
-		}
+		cobra.CheckErr(err)
 
 		toolchainGoPath := strings.TrimSpace(string(out))
 		goPaths = filepath.SplitList(toolchainGoPath)
 		if len(goPaths) == 0 {
-			er("$GOPATH is not set")
+			cobra.CheckErr("$GOPATH is not set")
 		}
 	}
 	srcPaths = make([]string, 0, len(goPaths))
 	for _, goPath := range goPaths {
 		srcPaths = append(srcPaths, filepath.Join(goPath, "src"))
 	}
 }
-
-func er(msg interface{}) {
-	fmt.Println("Error:", msg)
-	os.Exit(1)
-}

cobra/cmd/helpers_test.go

@@ -0,0 +1,9 @@
+package cmd
+
+import "testing"
+
+func assertNoErr(t *testing.T, e error) {
+	if e != nil {
+		t.Error(e)
+	}
+}

cobra/cmd/init.go

@@ -39,17 +39,15 @@ and the appropriate structure for a Cobra-based CLI application.
 		Run: func(_ *cobra.Command, args []string) {
 
 			projectPath, err := initializeProject(args)
-			if err != nil {
-				er(err)
-			}
+			cobra.CheckErr(err)
 			fmt.Printf("Your Cobra application is ready at\n%s\n", projectPath)
 		},
 	}
 )
 
 func init() {
 	initCmd.Flags().StringVar(&pkgName, "pkg-name", "", "fully qualified pkg name")
-	initCmd.MarkFlagRequired("pkg-name")
+	cobra.CheckErr(initCmd.MarkFlagRequired("pkg-name"))
 }
 
 func initializeProject(args []string) (string, error) {

cobra/cmd/init_test.go

@@ -59,7 +59,7 @@ func TestGoldenInitCmd(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 
-			initCmd.Flags().Set("pkg-name", tt.pkgName)
+			assertNoErr(t, initCmd.Flags().Set("pkg-name", tt.pkgName))
 			viper.Set("useViper", true)
 			projectPath, err := initializeProject(tt.args)
 			defer func() {

cobra/cmd/licenses.go

@@ -16,9 +16,11 @@
 package cmd
 
 import (
+	"fmt"
 	"strings"
 	"time"
 
+	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 )
 
@@ -92,7 +94,7 @@ func copyrightLine() string {
 func findLicense(name string) License {
 	found := matchLicense(name)
 	if found == "" {
-		er("unknown license: " + name)
+		cobra.CheckErr(fmt.Errorf("unknown license: " + name))
 	}
 	return Licenses[found]
 }

cobra/cmd/project.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"text/template"
 
+	"github.com/spf13/cobra"
 	"github.com/spf13/cobra/cobra/tpl"
 )
 
@@ -49,7 +50,7 @@ func (p *Project) Create() error {
 
 	// create cmd/root.go
 	if _, err = os.Stat(fmt.Sprintf("%s/cmd", p.AbsolutePath)); os.IsNotExist(err) {
-		os.Mkdir(fmt.Sprintf("%s/cmd", p.AbsolutePath), 0751)
+		cobra.CheckErr(os.Mkdir(fmt.Sprintf("%s/cmd", p.AbsolutePath), 0751))
 	}
 	rootFile, err := os.Create(fmt.Sprintf("%s/cmd/root.go", p.AbsolutePath))
 	if err != nil {

cobra/cmd/root.go

@@ -47,8 +47,8 @@ func init() {
 	rootCmd.PersistentFlags().StringP("author", "a", "YOUR NAME", "author name for copyright attribution")
 	rootCmd.PersistentFlags().StringVarP(&userLicense, "license", "l", "", "name of license for the project")
 	rootCmd.PersistentFlags().Bool("viper", true, "use Viper for configuration")
-	viper.BindPFlag("author", rootCmd.PersistentFlags().Lookup("author"))
-	viper.BindPFlag("useViper", rootCmd.PersistentFlags().Lookup("viper"))
+	cobra.CheckErr(viper.BindPFlag("author", rootCmd.PersistentFlags().Lookup("author")))
+	cobra.CheckErr(viper.BindPFlag("useViper", rootCmd.PersistentFlags().Lookup("viper")))
 	viper.SetDefault("author", "NAME HERE <EMAIL ADDRESS>")
 	viper.SetDefault("license", "apache")
 
@@ -63,9 +63,7 @@ func initConfig() {
 	} else {
 		// Find home directory.
 		home, err := homedir.Dir()
-		if err != nil {
-			er(err)
-		}
+		cobra.CheckErr(err)
 
 		// Search config in home directory with name ".cobra" (without extension).
 		viper.AddConfigPath(home)

cobra/cmd/testdata/root.go.golden

@@ -44,10 +44,7 @@ to quickly create a Cobra application.`,
 // Execute adds all child commands to the root command and sets flags appropriately.
 // This is called by main.main(). It only needs to happen once to the rootCmd.
 func Execute() {
-	if err := rootCmd.Execute(); err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
+	cobra.CheckErr(rootCmd.Execute())
 }
 
 func init() {
@@ -72,10 +69,7 @@ func initConfig() {
 	} else {
 		// Find home directory.
 		home, err := homedir.Dir()
-		if err != nil {
-			fmt.Fprintln(os.Stderr, err)
-			os.Exit(1)
-		}
+		cobra.CheckErr(err)
 
 		// Search config in home directory with name ".testproject" (without extension).
 		viper.AddConfigPath(home)

cobra/tpl/main.go

@@ -53,10 +53,7 @@ to quickly create a Cobra application.` + "`" + `,
 // Execute adds all child commands to the root command and sets flags appropriately.
 // This is called by main.main(). It only needs to happen once to the rootCmd.
 func Execute() {
-	if err := rootCmd.Execute(); err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
+	cobra.CheckErr(rootCmd.Execute())
 }
 
 func init() {
@@ -85,10 +82,7 @@ func initConfig() {
 	} else {
 		// Find home directory.
 		home, err := homedir.Dir()
-		if err != nil {
-			fmt.Fprintln(os.Stderr, err)
-			os.Exit(1)
-		}
+		cobra.CheckErr(err)
 
 		// Search config in home directory with name ".{{ .AppName }}" (without extension).
 		viper.AddConfigPath(home)

cobra_test.go

@@ -5,6 +5,12 @@ import (
 	"text/template"
 )
 
+func assertNoErr(t *testing.T, e error) {
+	if e != nil {
+		t.Error(e)
+	}
+}
+
 func TestAddTemplateFunctions(t *testing.T) {
 	AddTemplateFunc("t", func() bool { return true })
 	AddTemplateFuncs(template.FuncMap{