Prevent cobra-init from overwriting files

Running `cobra-cli init` or `cobra-cli add` would overwrite existing
files without warning, which could result in unexpected loss of data.
This commit modifies cobra-cli so that by default it will not
overwrite files, and adds the `--force` flag to the `init` and `add`
subcommands to allow it to overwrite files.

Closes spf13#59

cmd/add.go

@@ -43,6 +43,9 @@ Example: cobra add server -> resulting in a new cmd/server.go`,
 				cobra.CheckErr(fmt.Errorf("add needs a name for the command"))
 			}
 
+			force, err := cmd.Flags().GetBool("force")
+			cobra.CheckErr(err)
+
 			wd, err := os.Getwd()
 			cobra.CheckErr(err)
 
@@ -57,7 +60,7 @@ Example: cobra add server -> resulting in a new cmd/server.go`,
 				},
 			}
 
-			cobra.CheckErr(command.Create())
+			cobra.CheckErr(command.Create(force))
 
 			fmt.Printf("%s created at %s\n", command.CmdName, command.AbsolutePath)
 		},
@@ -67,6 +70,7 @@ 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().BoolP("force", "f", false, "overwrite files")
 	cobra.CheckErr(addCmd.Flags().MarkDeprecated("package", "this operation has been removed."))
 }
 

cmd/add_test.go

@@ -18,8 +18,8 @@ func TestGoldenAddCmd(t *testing.T) {
 	}
 	defer os.RemoveAll(command.AbsolutePath)
 
-	assertNoErr(t, command.Project.Create())
-	assertNoErr(t, command.Create())
+	assertNoErr(t, command.Project.Create(false))
+	assertNoErr(t, command.Create(false))
 
 	generatedFile := fmt.Sprintf("%s/cmd/%s.go", command.AbsolutePath, command.CmdName)
 	goldenFile := fmt.Sprintf("testdata/%s.go.golden", command.CmdName)

cmd/init.go

@@ -37,8 +37,10 @@ and the appropriate structure for a Cobra-based CLI application.
 Cobra init must be run inside of a go module (please run "go mod init <MODNAME>" first)
 `,
 
-		Run: func(_ *cobra.Command, args []string) {
-			projectPath, err := initializeProject(args)
+		Run: func(cmd *cobra.Command, args []string) {
+			force, err := cmd.Flags().GetBool("force")
+			cobra.CheckErr(err)
+			projectPath, err := initializeProject(force, args)
 			cobra.CheckErr(err)
 			cobra.CheckErr(goGet("github.com/spf13/cobra"))
 			if viper.GetBool("useViper") {
@@ -49,7 +51,11 @@ Cobra init must be run inside of a go module (please run "go mod init <MODNAME>"
 	}
 )
 
-func initializeProject(args []string) (string, error) {
+func init() {
+	initCmd.Flags().BoolP("force", "f", false, "overwrite files")
+}
+
+func initializeProject(force bool, args []string) (string, error) {
 	wd, err := os.Getwd()
 	if err != nil {
 		return "", err
@@ -72,7 +78,7 @@ func initializeProject(args []string) (string, error) {
 		AppName:      path.Base(modName),
 	}
 
-	if err := project.Create(); err != nil {
+	if err := project.Create(force); err != nil {
 		return "", err
 	}
 

cmd/init_test.go

@@ -49,7 +49,7 @@ func TestGoldenInitCmd(t *testing.T) {
 
 			viper.Set("useViper", true)
 			viper.Set("license", "apache")
-			projectPath, err := initializeProject(tt.args)
+			projectPath, err := initializeProject(false, tt.args)
 			defer func() {
 				if projectPath != "" {
 					os.RemoveAll(projectPath)

cmd/project.go

@@ -9,32 +9,36 @@ import (
 	"github.com/spf13/cobra-cli/tpl"
 )
 
-// Project contains name, license and paths to projects.
-type Project struct {
-	// v2
-	PkgName      string
-	Copyright    string
-	AbsolutePath string
-	Legal        License
-	Viper        bool
-	AppName      string
-}
+type (
+	// Project contains name, license and paths to projects.
+	Project struct {
+		// v2
+		PkgName      string
+		Copyright    string
+		AbsolutePath string
+		Legal        License
+		Viper        bool
+		AppName      string
+	}
 
-type Command struct {
-	CmdName   string
-	CmdParent string
-	*Project
-}
+	Command struct {
+		CmdName   string
+		CmdParent string
+		*Project
+	}
 
-func (p *Project) Create() error {
-	// check if AbsolutePath exists
-	if _, err := os.Stat(p.AbsolutePath); os.IsNotExist(err) {
-		// create directory
-		if err := os.Mkdir(p.AbsolutePath, 0754); err != nil {
-			return err
-		}
+	createFileFunc func(p *Project) error
+)
+
+var (
+	projectFiles = map[string]createFileFunc{
+		"%s/main.go":     createMain,
+		"%s/cmd/root.go": createRootCmd,
+		"%s/LICENSE":     createLicenseFile,
 	}
+)
 
+func createMain(p *Project) error {
 	// create main.go
 	mainFile, err := os.Create(fmt.Sprintf("%s/main.go", p.AbsolutePath))
 	if err != nil {
@@ -43,13 +47,12 @@ func (p *Project) Create() error {
 	defer mainFile.Close()
 
 	mainTemplate := template.Must(template.New("main").Parse(string(tpl.MainTemplate())))
-	err = mainTemplate.Execute(mainFile, p)
-	if err != nil {
-		return err
-	}
+	return mainTemplate.Execute(mainFile, p)
+}
 
+func createRootCmd(p *Project) error {
 	// create cmd/root.go
-	if _, err = os.Stat(fmt.Sprintf("%s/cmd", p.AbsolutePath)); os.IsNotExist(err) {
+	if _, err := os.Stat(fmt.Sprintf("%s/cmd", p.AbsolutePath)); os.IsNotExist(err) {
 		cobra.CheckErr(os.Mkdir(fmt.Sprintf("%s/cmd", p.AbsolutePath), 0751))
 	}
 	rootFile, err := os.Create(fmt.Sprintf("%s/cmd/root.go", p.AbsolutePath))
@@ -59,16 +62,10 @@ func (p *Project) Create() error {
 	defer rootFile.Close()
 
 	rootTemplate := template.Must(template.New("root").Parse(string(tpl.RootTemplate())))
-	err = rootTemplate.Execute(rootFile, p)
-	if err != nil {
-		return err
-	}
-
-	// create license
-	return p.createLicenseFile()
+	return rootTemplate.Execute(rootFile, p)
 }
 
-func (p *Project) createLicenseFile() error {
+func createLicenseFile(p *Project) error {
 	data := map[string]interface{}{
 		"copyright": copyrightLine(),
 	}
@@ -82,7 +79,39 @@ func (p *Project) createLicenseFile() error {
 	return licenseTemplate.Execute(licenseFile, data)
 }
 
-func (c *Command) Create() error {
+func (p *Project) Create(force bool) error {
+	// check if AbsolutePath exists
+	if _, err := os.Stat(p.AbsolutePath); os.IsNotExist(err) {
+		// create directory
+		if err := os.Mkdir(p.AbsolutePath, 0754); err != nil {
+			return err
+		}
+	}
+
+	// Check to make sure we don't overwrite things unless we have --force
+	if !force {
+		for path, _ := range projectFiles {
+			abspath := fmt.Sprintf(path, p.AbsolutePath)
+			if _, err := os.Stat(abspath); err == nil {
+				return fmt.Errorf("%s already exists; use --force to overwrite", abspath)
+			}
+		}
+	}
+
+	for _, createFunc := range projectFiles {
+		if err := createFunc(p); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (c *Command) Create(force bool) error {
+	abspath := fmt.Sprintf("%s/cmd/%s.go", c.AbsolutePath, c.CmdName)
+	if _, err := os.Stat(abspath); err == nil && !force {
+		return fmt.Errorf("%s already exists; use --force to overwrite", abspath)
+	}
 	cmdFile, err := os.Create(fmt.Sprintf("%s/cmd/%s.go", c.AbsolutePath, c.CmdName))
 	if err != nil {
 		return err