Incorporating pull request feedback.

- Renamed completer to be cobra_completer to match docs
- Added whitespace after each completion
- Implemented ShellCompDirectiveError, ShellCompDirectiveNoSpace, ShellCompDirectiveNoFileComp
- Disabled active help as it isn't supported by nushell
- Added nushell to the default completion command

completions.go

@@ -798,14 +798,47 @@ to your powershell profile.
 				return cmd.Root().GenPowerShellCompletion(out)
 			}
 			return cmd.Root().GenPowerShellCompletionWithDesc(out)
-
 		},
 	}
 	if haveNoDescFlag {
 		powershell.Flags().BoolVar(&noDesc, compCmdNoDescFlagName, compCmdNoDescFlagDefault, compCmdNoDescFlagDesc)
 	}
 
-	completionCmd.AddCommand(bash, zsh, fish, powershell)
+	nushell := &Command{
+		Use:   "nushell",
+		Short: fmt.Sprintf(shortDesc, "nushell"),
+		Long: fmt.Sprintf(`Generate the autocompletion script for nushell.
+
+To configure completions:
+      
+  # 1. Copy the output of the command below:
+  > %[1]s completion nushell 
+
+  # 2. Edit the nushell config file:
+  > config nu
+
+  # 3. Paste above the "let-env config" line.
+
+  # 4. Change the config block's external_completer line to be 
+  external_completer: $cobra_completer
+
+  # 5. You will need to start a new shell for this setup to take effect.
+
+`, c.Root().Name()),
+		Args:              NoArgs,
+		ValidArgsFunction: NoFileCompletions,
+		RunE: func(cmd *Command, args []string) error {
+			if noDesc {
+				return cmd.Root().GenPowerShellCompletion(out)
+			}
+			return cmd.Root().GenPowerShellCompletionWithDesc(out)
+		},
+	}
+	if haveNoDescFlag {
+		nushell.Flags().BoolVar(&noDesc, compCmdNoDescFlagName, compCmdNoDescFlagDefault, compCmdNoDescFlagDesc)
+	}
+
+	completionCmd.AddCommand(bash, zsh, fish, powershell, nushell)
 }
 
 func findFlag(cmd *Command, name string) *pflag.Flag {
@@ -838,7 +871,7 @@ func CompDebug(msg string, printToStdErr bool) {
 	// variable BASH_COMP_DEBUG_FILE to the path of some file to be used.
 	if path := os.Getenv("BASH_COMP_DEBUG_FILE"); path != "" {
 		f, err := os.OpenFile(path,
-			os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+			os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
 		if err == nil {
 			defer f.Close()
 			WriteStringAndCheck(f, msg)

nushell_completions.go

@@ -16,31 +16,39 @@ package cobra
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"os"
 )
 
 func (c *Command) GenNushellCompletion(w io.Writer) error {
 	buf := new(bytes.Buffer)
-	WriteStringAndCheck(buf, `
+	WriteStringAndCheck(buf, fmt.Sprintf(`
 # An external configurator that works with any cobra based
 # command line application (e.g. kubectl, minikube)
-let cobra_configurator = {|spans| 
+let cobra_completer = {|spans| 
+
+  let ShellCompDirectiveError = %[1]d
+  let ShellCompDirectiveNoSpace = %[2]d
+  let ShellCompDirectiveNoFileComp = %[3]d
+  let ShellCompDirectiveFilterFileExt = %[4]d
+  let ShellCompDirectiveFilterDirs = %[5]d
  
   let cmd = $spans.0
+  let last_span = ($spans | last | str trim)
 
   # skip the first entry in the span (the command) and join the rest of the span to create __complete args
   let cmd_args = ($spans | skip 1 | str join ' ') 
 
   # If the last span entry was empty add "" to the end of the command args
-  let cmd_args = if ($spans | last | str trim | is-empty) {
+  let cmd_args = if ($last_span | is-empty) {
     $'($cmd_args) ""'
   } else {
     $cmd_args
   }
 
-  # The full command to be executed
-  let full_cmd = $'($cmd) __complete ($cmd_args)'
+  # The full command to be executed with active help disable (Nushell does not support active help)
+  let full_cmd = $'($cmd)_ACTIVE_HELP=0 ($cmd) __complete ($cmd_args)'
 
   # Since nushell doesn't have anything like eval, execute in a subshell
   let result = (do -i { nu -c $"'($full_cmd)'" } | complete)
@@ -48,16 +56,33 @@ let cobra_configurator = {|spans|
   # Create a record with all completion related info. 
   # directive and directive_str are for posterity
   let stdout_lines = ($result.stdout | lines)
-  let $completions = ($stdout_lines | drop | parse -r '([\w\-\.:\+]*)\t?(.*)' | rename value description)
+  let directive = ($stdout_lines | last | str trim | str replace ":" "" | into int)
+  let completions = ($stdout_lines | drop | parse -r '([\w\-\.:\+\=]*)\t?(.*)' | rename value description)
 
-  let result = ({
-    completions: $completions
-    directive_str: ($result.stderr)
-    directive: ($stdout_lines | last)
-  })
+  # Add space at the end of each completion
+  let completions = if $directive != $ShellCompDirectiveNoSpace {
+    ($completions | each {|it| {value: $"($it.value) ", description: $it.description}})
+  } else {
+    $completions
+  }
 
-  $result.completions
-}`)
+  if $last_span =~ '=$' {
+    # return flag as part of the completion so that it doesn't get replaced
+    $completions | each {|it| $"($last_span)($it.value)" }
+  } else if $directive == $ShellCompDirectiveNoFileComp {
+    # Allow empty results as this will stop file completion
+    $completions
+  } else if ($completions | is-empty)  or  $directive == $ShellCompDirectiveError {
+    # Not returning null causes file completions to break
+    # Return null if there are no completions or ShellCompDirectiveError 
+    null
+  } else {
+    $completions
+  }
+
+}
+`, ShellCompDirectiveError, ShellCompDirectiveNoSpace, ShellCompDirectiveNoFileComp,
+		ShellCompDirectiveFilterFileExt, ShellCompDirectiveFilterDirs))
 
 	_, err := buf.WriteTo(w)
 	return err

nushell_completions_test.go

@@ -38,7 +38,7 @@ func TestGenNushellCompletion(t *testing.T) {
 	assertNoErr(t, rootCmd.GenNushellCompletion(buf))
 	output := buf.String()
 
-	check(t, output, "let full_cmd = $'($cmd) __complete ($cmd_args)'")
+	check(t, output, "let full_cmd = $'($cmd)_ACTIVE_HELP=0 ($cmd) __complete ($cmd_args)'")
 }
 
 func TestGenNushellCompletionFile(t *testing.T) {