Add powershell completion

- Add code for powersehll complition available in cobra
- Add documentation for powershell completion
- Add changelog for pr3925

changelog/unreleased/pull-3925

@@ -0,0 +1,6 @@
+Enhancement: Provide command completion for powershell
+
+Restic allows generation of completion files for bash, fish and zsh. Now powershell
+is supported, too.
+
+https://github.com/restic/restic/pull/3925/files

cmd/restic/cmd_generate.go

@@ -10,7 +10,7 @@ import (
 
 var cmdGenerate = &cobra.Command{
 	Use:   "generate [flags]",
-	Short: "Generate manual pages and auto-completion files (bash, fish, zsh)",
+	Short: "Generate manual pages and auto-completion files (bash, fish, zsh, powershell)",
 	Long: `
 The "generate" command writes automatically generated files (like the man pages
 and the auto-completion files for bash, fish and zsh).
@@ -29,6 +29,7 @@ type generateOptions struct {
 	BashCompletionFile       string
 	FishCompletionFile       string
 	ZSHCompletionFile        string
+	PowerShellCompletionFile string
 }
 
 var genOpts generateOptions
@@ -40,6 +41,7 @@ func init() {
 	fs.StringVar(&genOpts.BashCompletionFile, "bash-completion", "", "write bash completion `file`")
 	fs.StringVar(&genOpts.FishCompletionFile, "fish-completion", "", "write fish completion `file`")
 	fs.StringVar(&genOpts.ZSHCompletionFile, "zsh-completion", "", "write zsh completion `file`")
+	fs.StringVar(&genOpts.PowerShellCompletionFile, "powershell-completion", "", "write powershell completion `file`")
 }
 
 func writeManpages(dir string) error {
@@ -75,6 +77,11 @@ func writeZSHCompletion(file string) error {
 	return cmdRoot.GenZshCompletionFile(file)
 }
 
+func writePowerShellCompletion(file string) error {
+	Verbosef("writing powershell completion file to %v\n", file)
+	return cmdRoot.GenPowerShellCompletionFile(file)
+}
+
 func runGenerate(cmd *cobra.Command, args []string) error {
 	if genOpts.ManDir != "" {
 		err := writeManpages(genOpts.ManDir)
@@ -104,6 +111,13 @@ func runGenerate(cmd *cobra.Command, args []string) error {
 		}
 	}
 
+	if genOpts.PowerShellCompletionFile != "" {
+		err := writePowerShellCompletion(genOpts.PowerShellCompletionFile)
+		if err != nil {
+			return err
+		}
+	}
+
 	var empty generateOptions
 	if genOpts == empty {
 		return errors.Fatal("nothing to do, please specify at least one output file/dir")

doc/020_installation.rst

@@ -313,14 +313,14 @@ compiler. Building restic with gccgo may work, but is not supported.
 Autocompletion
 **************
 
-Restic can write out man pages and bash/fish/zsh compatible autocompletion scripts:
+Restic can write out man pages and bash/fish/zsh/powershell compatible autocompletion scripts:
 
 .. code-block:: console
 
     $ ./restic generate --help
 
     The "generate" command writes automatically generated files (like the man pages
-    and the auto-completion files for bash, fish and zsh).
+    and the auto-completion files for bash, fish, zsh and powershell).
 
     Usage:
       restic generate [flags] [command]
@@ -330,6 +330,7 @@ Restic can write out man pages and bash/fish/zsh compatible autocompletion scrip
           --fish-completion file   write fish completion file
       -h, --help                   help for generate
           --man directory          write man pages to directory
+          --powershell-completion  write powershell completion file
           --zsh-completion file    write zsh completion file
 
 Example for using sudo to write a bash completion script directly to the system-wide location:

helpers/prepare-release/main.go

@@ -290,6 +290,7 @@ func generateFiles() {
 	run("./restic-generate.temp", "generate",
 		"--man", "doc/man",
 		"--zsh-completion", "doc/zsh-completion.zsh",
+		"--powershell-completion", "doc/powershell-completion.ps1",
 		"--fish-completion", "doc/fish-completion.fish",
 		"--bash-completion", "doc/bash-completion.sh")
 	rm("restic-generate.temp")