make -h work with imported targets (magefile#335)

fixes magefile#249 Forgot to allow help to be called on imported targets. Kinda useful, eh?

Author: natefinch

mage/import_test.go

@@ -38,6 +38,104 @@ Targets:
 }
 }
 
+func TestMageImportsHelp(t *testing.T) {
+stdout := &bytes.Buffer{}
+stderr := &bytes.Buffer{}
+inv := Invocation{
+Dir: "./testdata/mageimport",
+Stdout: stdout,
+Stderr: stderr,
+Help: true,
+Args: []string{"buildSubdir"},
+}
+
+code := Invoke(inv)
+if code != 0 {
+t.Fatalf("expected to exit with code 0, but got %v, stderr:\n%s", code, stderr)
+}
+actual := stdout.String()
+expected := `
+BuildSubdir Builds stuff.
+
+Usage:
+
+mage buildsubdir
+
+`[1:]
+
+if actual != expected {
+t.Logf("expected: %q", expected)
+t.Logf(" actual: %q", actual)
+t.Fatalf("expected:\n%v\n\ngot:\n%v", expected, actual)
+}
+}
+
+func TestMageImportsHelpNamed(t *testing.T) {
+stdout := &bytes.Buffer{}
+stderr := &bytes.Buffer{}
+inv := Invocation{
+Dir: "./testdata/mageimport",
+Stdout: stdout,
+Stderr: stderr,
+Help: true,
+Args: []string{"zz:buildSubdir2"},
+}
+
+code := Invoke(inv)
+if code != 0 {
+t.Fatalf("expected to exit with code 0, but got %v, stderr:\n%s", code, stderr)
+}
+actual := stdout.String()
+expected := `
+BuildSubdir2 Builds stuff.
+
+Usage:
+
+mage zz:buildsubdir2
+
+`[1:]
+
+if actual != expected {
+t.Logf("expected: %q", expected)
+t.Logf(" actual: %q", actual)
+t.Fatalf("expected:\n%v\n\ngot:\n%v", expected, actual)
+}
+}
+
+func TestMageImportsHelpNamedNS(t *testing.T) {
+stdout := &bytes.Buffer{}
+stderr := &bytes.Buffer{}
+inv := Invocation{
+Dir: "./testdata/mageimport",
+Stdout: stdout,
+Stderr: stderr,
+Help: true,
+Args: []string{"zz:ns:deploy2"},
+}
+
+code := Invoke(inv)
+if code != 0 {
+t.Fatalf("expected to exit with code 0, but got %v, stderr:\n%s", code, stderr)
+}
+actual := stdout.String()
+expected := `
+Deploy2 deploys stuff.
+
+Usage:
+
+mage zz:ns:deploy2
+
+Aliases: nsd2
+
+`[1:]
+
+if actual != expected {
+t.Logf("expected: %q", expected)
+t.Logf(" actual: %q", actual)
+t.Fatalf("expected:\n%v\n\ngot:\n%v", expected, actual)
+}
+}
+
 func TestMageImportsRoot(t *testing.T) {
 stdout := &bytes.Buffer{}
 stderr := &bytes.Buffer{}

mage/template.go

@@ -339,7 +339,27 @@ Options:
 os.Exit(2)
 }
 switch strings.ToLower(args.Args[0]) {
-{{range .Funcs}}case "{{lower .TargetName}}":
+{{range .Funcs -}}
+case "{{lower .TargetName}}":
+{{if ne .Comment "" -}}
+fmt.Println({{printf "%q" .Comment}})
+fmt.Println()
+{{end}}
+fmt.Print("Usage:\n\n\t{{$.BinaryName}} {{lower .TargetName}}{{range .Args}} <{{.Name}}>{{end}}\n\n")
+var aliases []string
+{{- $name := .Name -}}
+{{- $recv := .Receiver -}}
+{{range $alias, $func := $.Aliases}}
+{{if and (eq $name $func.Name) (eq $recv $func.Receiver)}}aliases = append(aliases, "{{$alias}}"){{end -}}
+{{- end}}
+if len(aliases) > 0 {
+fmt.Printf("Aliases: %s\n\n", strings.Join(aliases, ", "))
+}
+return
+{{end -}}
+{{range .Imports -}}
+{{range .Info.Funcs -}}
+case "{{lower .TargetName}}":
 {{if ne .Comment "" -}}
 fmt.Println({{printf "%q" .Comment}})
 fmt.Println()
@@ -355,7 +375,8 @@ Options:
 fmt.Printf("Aliases: %s\n\n", strings.Join(aliases, ", "))
 }
 return
-{{end}}
+{{end -}}
+{{end -}}
 default:
 logger.Printf("Unknown target: %q\n", args.Args[0])
 os.Exit(2)