feat: completions command

Taskfile.yml

@@ -27,8 +27,13 @@ tasks:
       - go install -v ./cmd/task
 
   generate:
+    desc: Run all generation tasks
+    aliases: [g, gen]
+    deps: [generate:mocks, generate:fixtures]
+
+  generate:mocks:
     desc: Runs Go generate to create mocks
-    aliases: [gen, g]
+    aliases: [g:mocks, gen:mocks]
     deps: [install:mockery]
     sources:
       - "internal/fingerprint/checker.go"
@@ -38,6 +43,16 @@ tasks:
       - "{{.BIN}}/mockery --dir ./internal/fingerprint --name SourcesCheckable"
       - "{{.BIN}}/mockery --dir ./internal/fingerprint --name StatusCheckable"
 
+  generate:fixtures:
+    desc: Generates fixtures
+    aliases: [g:fixtures, gen:fixtures]
+    sources:
+      - "internal/completion/templates/*"
+    generates:
+      - "internal/completion/testdata/**/*.golden"
+    cmds:
+      - go test ./internal/completion -update
+
   install:mockery:
     desc: Installs mockgen; a tool to generate mock files
     vars:

cmd/task/task.go

@@ -15,6 +15,7 @@ import (
 	"github.com/go-task/task/v3"
 	"github.com/go-task/task/v3/args"
 	"github.com/go-task/task/v3/errors"
+	"github.com/go-task/task/v3/internal/completion"
 	"github.com/go-task/task/v3/internal/logger"
 	"github.com/go-task/task/v3/internal/sort"
 	ver "github.com/go-task/task/v3/internal/version"
@@ -47,6 +48,7 @@ var flags struct {
 	version     bool
 	help        bool
 	init        bool
+	completion  string
 	list        bool
 	listAll     bool
 	listJson    bool
@@ -104,6 +106,7 @@ func run() error {
 	pflag.BoolVar(&flags.version, "version", false, "Show Task version.")
 	pflag.BoolVarP(&flags.help, "help", "h", false, "Shows Task usage.")
 	pflag.BoolVarP(&flags.init, "init", "i", false, "Creates a new Taskfile.yml in the current folder.")
+	pflag.StringVar(&flags.completion, "completion", "", "Generates shell completion script.")
 	pflag.BoolVarP(&flags.list, "list", "l", false, "Lists tasks with description of current Taskfile.")
 	pflag.BoolVarP(&flags.listAll, "list-all", "a", false, "Lists tasks with or without a description.")
 	pflag.BoolVarP(&flags.listJson, "json", "j", false, "Formats task list as JSON.")
@@ -226,6 +229,15 @@ func run() error {
 		return err
 	}
 
+	if flags.completion != "" {
+		script, err := completion.Compile(flags.completion, e.Taskfile.Tasks)
+		if err != nil {
+			return err
+		}
+		fmt.Println(script)
+		return nil
+	}
+
 	if listOptions.ShouldListTasks() {
 		foundTasks, err := e.ListTasks(listOptions)
 		if err != nil {

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/mitchellh/hashstructure/v2 v2.0.2
 	github.com/radovskyb/watcher v1.0.7
 	github.com/sajari/fuzzy v1.0.0
+	github.com/sebdah/goldie/v2 v2.5.3
 	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.8.2
 	golang.org/x/exp v0.0.0-20230212135524-a684f29349b6
@@ -24,6 +25,7 @@ require (
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.17 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/sergi/go-diff v1.0.0 // indirect
 	github.com/stretchr/objx v0.5.0 // indirect
 	golang.org/x/sys v0.6.0 // indirect
 	golang.org/x/term v0.3.0 // indirect

go.sum

@@ -23,19 +23,25 @@ github.com/mattn/go-zglob v0.0.4 h1:LQi2iOm0/fGgu80AioIJ/1j9w9Oh+9DZ39J4VAGzHQM=
 github.com/mattn/go-zglob v0.0.4/go.mod h1:MxxjyoXXnMxfIpxTK2GAkw1w8glPsQILx3N5wrKakiY=
 github.com/mitchellh/hashstructure/v2 v2.0.2 h1:vGKWl0YJqUNxE8d+h8f6NJLcCJrgbhC4NcD46KavDd4=
 github.com/mitchellh/hashstructure/v2 v2.0.2/go.mod h1:MG3aRVU/N29oo/V/IhBX8GR/zz4kQkprJgF2EVszyDE=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/radovskyb/watcher v1.0.7 h1:AYePLih6dpmS32vlHfhCeli8127LzkIgwJGcwwe8tUE=
 github.com/radovskyb/watcher v1.0.7/go.mod h1:78okwvY5wPdzcb1UYnip1pvrZNIVEIh/Cm+ZuvsUYIg=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/sajari/fuzzy v1.0.0 h1:+FmwVvJErsd0d0hAPlj4CxqxUtQY/fOoY0DwX4ykpRY=
 github.com/sajari/fuzzy v1.0.0/go.mod h1:OjYR6KxoWOe9+dOlXeiCJd4dIbED4Oo8wpS89o0pwOo=
+github.com/sebdah/goldie/v2 v2.5.3 h1:9ES/mNN+HNUbNWpVAlrzuZ7jE+Nrczbj8uFRjM7624Y=
+github.com/sebdah/goldie/v2 v2.5.3/go.mod h1:oZ9fp0+se1eapSRjfYbsV/0Hqhbuu3bJVvKI/NNtssI=
+github.com/sergi/go-diff v1.0.0 h1:Kpca3qRNrduNnOQeazBd0ysaKrUJiIuISHxogkT9RPQ=
+github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0 h1:1zr/of2m5FGMsad5YfcqgdqdWrIhu+EBEJRhR1U7z/c=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=

internal/completion/completion.go

@@ -0,0 +1,71 @@
+package completion
+
+import (
+	"bytes"
+	"embed"
+	"fmt"
+	"os"
+	"path/filepath"
+	"text/template"
+
+	"github.com/spf13/pflag"
+
+	"github.com/go-task/task/v3/internal/templater"
+	"github.com/go-task/task/v3/taskfile"
+)
+
+type TemplateValues struct {
+	Entrypoint string
+	Flags      []*pflag.Flag
+	Tasks      []*taskfile.Task
+}
+
+//go:embed templates/*
+var templates embed.FS
+
+func Compile(completion string, tasks taskfile.Tasks) (string, error) {
+	// Get the file extension for the selected shell
+	var ext string
+	switch completion {
+	case "bash":
+		ext = "bash"
+	case "fish":
+		ext = "fish"
+	case "powershell":
+		ext = "ps1"
+	case "zsh":
+		ext = "zsh"
+	default:
+		return "", fmt.Errorf("unknown completion shell: %s", completion)
+	}
+
+	// Load the template
+	templateName := fmt.Sprintf("task.tpl.%s", ext)
+	tpl, err := template.New(templateName).
+		Funcs(templater.TemplateFuncs).
+		ParseFS(templates, filepath.Join("templates", templateName))
+	if err != nil {
+		return "", err
+	}
+
+	values := TemplateValues{
+		Entrypoint: os.Args[0],
+		Flags:      getFlagNames(),
+		Tasks:      tasks.Values(),
+	}
+
+	var buf bytes.Buffer
+	if err := tpl.Execute(&buf, values); err != nil {
+		return "", err
+	}
+
+	return buf.String(), nil
+}
+
+func getFlagNames() []*pflag.Flag {
+	var flags []*pflag.Flag
+	pflag.VisitAll(func(flag *pflag.Flag) {
+		flags = append(flags, flag)
+	})
+	return flags
+}

internal/completion/completion_test.go

@@ -0,0 +1,72 @@
+package completion
+
+import (
+	"os"
+	"testing"
+
+	"github.com/sebdah/goldie/v2"
+	"github.com/spf13/pflag"
+	"github.com/stretchr/testify/require"
+
+	"github.com/go-task/task/v3/internal/orderedmap"
+	"github.com/go-task/task/v3/taskfile"
+)
+
+var (
+	tasks = taskfile.Tasks{
+		OrderedMap: orderedmap.FromMapWithOrder(
+			map[string]*taskfile.Task{
+				"foo": {
+					Task: "foo",
+					Cmds: []*taskfile.Cmd{
+						{Cmd: "echo foo"},
+					},
+					Desc:    "Prints foo",
+					Aliases: []string{"f"},
+				},
+				"bar": {
+					Task: "bar",
+					Cmds: []*taskfile.Cmd{
+						{Cmd: "echo bar"},
+					},
+					Desc:    "Prints bar",
+					Aliases: []string{"b"},
+				},
+			},
+			[]string{"foo", "bar"},
+		),
+	}
+	flags struct {
+		foo    string
+		bar    int
+		noDesc bool
+	}
+)
+
+func init() {
+	os.Args[0] = "task"
+	pflag.StringVarP(&flags.foo, "foo", "f", "default", "A regular flag")
+	pflag.IntVar(&flags.bar, "bar", 99, "A flag with no short variant")
+	pflag.BoolVar(&flags.noDesc, "no-desc", true, "")
+}
+
+func TestCompile(t *testing.T) {
+	tests := []struct {
+		shell string
+	}{
+		{shell: "bash"},
+		{shell: "fish"},
+		{shell: "powershell"},
+		{shell: "zsh"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.shell, func(t *testing.T) {
+			completion, err := Compile(tt.shell, tasks)
+			require.NoError(t, err)
+
+			g := goldie.New(t, goldie.WithTestNameForDir(true))
+			g.Assert(t, tt.shell, []byte(completion))
+		})
+	}
+}

internal/completion/testdata/TestCompile/bash.golden

@@ -0,0 +1,55 @@
+# vim: set tabstop=2 shiftwidth=2 expandtab:
+
+_GO_TASK_COMPLETION_LIST_OPTION='--list-all'
+
+function _task()
+{
+  local cur prev words cword
+  _init_completion -n : || return
+
+  # Check for `--` within command-line and quit or strip suffix.
+  local i
+  for i in "${!words[@]}"; do
+    if [ "${words[$i]}" == "--" ]; then
+      # Do not complete words following `--` passed to CLI_ARGS.
+      [ $cword -gt $i ] && return
+      # Remove the words following `--` to not put --list in CLI_ARGS.
+      words=( "${words[@]:0:$i}" )
+      break
+    fi
+  done
+
+  # Handle special arguments of options.
+  case "$prev" in
+    -d|--dir)
+      _filedir -d
+      return $?
+    ;;
+    -t|--taskfile)
+      _filedir yaml || return $?
+      _filedir yml
+      return $?
+    ;;
+    -o|--output)
+      COMPREPLY=( $( compgen -W "interleaved group prefixed" -- $cur ) )
+      return 0
+    ;;
+  esac
+
+  # Handle normal options.
+  case "$cur" in
+    -*)
+      COMPREPLY=( $( compgen -W "$(_parse_help $1)" -- $cur ) )
+      return 0
+    ;;
+  esac
+
+  # Prepare task name completions.
+  local tasks=( $( "${words[@]}" --silent $_GO_TASK_COMPLETION_LIST_OPTION 2> /dev/null ) )
+  COMPREPLY=( $( compgen -W "${tasks[*]}" -- "$cur" ) )
+
+  # Post-process because task names might contain colons.
+  __ltrim_colon_completions "$cur"
+}
+
+complete -F _task task

internal/completion/testdata/TestCompile/fish.golden

@@ -0,0 +1,37 @@
+set GO_TASK_PROGNAME task
+
+function __task_get_tasks --description "Prints all available tasks with their description"
+  # Read the list of tasks (and potential errors)
+  $GO_TASK_PROGNAME --list-all 2>&1 | read -lz rawOutput
+
+  # Return on non-zero exit code (for cases when there is no Taskfile found or etc.)
+  if test $status -ne 0
+    return
+  end
+
+  # Grab names and descriptions (if any) of the tasks
+  set -l output (echo $rawOutput | sed -e '1d; s/\* \(.*\):\s*\(.*\)\s*(aliases.*/\1\t\2/' -e 's/\* \(.*\):\s*\(.*\)/\1\t\2/'| string split0)
+  if test $output
+    echo $output
+  end
+end
+
+complete -c $GO_TASK_PROGNAME -d 'Runs the specified task(s). Falls back to the "default" task if no task name was specified, or lists all tasks if an unknown task name was
+specified.' -xa "(__task_get_tasks)"
+
+complete -c $GO_TASK_PROGNAME -s c -l color     -d 'colored output (default true)'
+complete -c $GO_TASK_PROGNAME -s d -l dir       -d 'sets directory of execution'
+complete -c $GO_TASK_PROGNAME      -l dry       -d 'compiles and prints tasks in the order that they would be run, without executing them'
+complete -c $GO_TASK_PROGNAME -s f -l force     -d 'forces execution even when the task is up-to-date'
+complete -c $GO_TASK_PROGNAME -s h -l help      -d 'shows Task usage'
+complete -c $GO_TASK_PROGNAME -s i -l init      -d 'creates a new Taskfile.yml in the current folder'
+complete -c $GO_TASK_PROGNAME -s l -l list      -d 'lists tasks with description of current Taskfile'
+complete -c $GO_TASK_PROGNAME -s o -l output    -d 'sets output style: [interleaved|group|prefixed]' -xa "interleaved group prefixed"
+complete -c $GO_TASK_PROGNAME -s p -l parallel  -d 'executes tasks provided on command line in parallel'
+complete -c $GO_TASK_PROGNAME -s s -l silent    -d 'disables echoing'
+complete -c $GO_TASK_PROGNAME      -l status    -d 'exits with non-zero exit code if any of the given tasks is not up-to-date'
+complete -c $GO_TASK_PROGNAME      -l summary   -d 'show summary about a task'
+complete -c $GO_TASK_PROGNAME -s t -l taskfile  -d 'choose which Taskfile to run. Defaults to "Taskfile.yml"'
+complete -c $GO_TASK_PROGNAME -s v -l verbose   -d 'enables verbose mode'
+complete -c $GO_TASK_PROGNAME      -l version   -d 'show Task version'
+complete -c $GO_TASK_PROGNAME -s w -l watch     -d 'enables watch of the given task'

internal/completion/testdata/TestCompile/powershell.golden

@@ -0,0 +1,8 @@
+$scriptBlock = {
+	param($commandName, $parameterName, $wordToComplete, $commandAst, $fakeBoundParameters )
+	$reg = "\* ($commandName.+?):"
+	$listOutput = $(task --list-all)
+	$listOutput | Select-String $reg -AllMatches | ForEach-Object { $_.Matches.Groups[1].Value }
+}
+
+Register-ArgumentCompleter -CommandName task -ScriptBlock $scriptBlock