actually parse the MAGEFILE_VERBOSE flag (#175)

* actually parse the verbose flag in case someone sets it to 0

mage/main.go

@@ -432,11 +432,11 @@ func Magefiles(magePath, goCmd string, stderr io.Writer, isDebug bool) ([]string
 	}
 	cmd.Dir = magePath
 	b, err = cmd.Output()
-	list = strings.TrimSpace(string(b))
-
 	if err != nil {
 		return fail(fmt.Errorf("failed to list mage gofiles: %v", err))
 	}
+
+	list = strings.TrimSpace(string(b))
 	files := []string{}
 	for _, f := range strings.Split(list, "||") {
 		if f != "" && !exclude[f] {

mage/main_test.go

@@ -191,7 +191,19 @@ func TestVerboseEnv(t *testing.T) {
 	if inv.Verbose != true {
 		t.Fatalf("expected %t, but got %t ", expected, inv.Verbose)
 	}
+}
+func TestVerboseFalseEnv(t *testing.T) {
+	os.Setenv("MAGEFILE_VERBOSE", "0")
+	defer os.Unsetenv("MAGEFILE_VERBOSE")
+	stdout := &bytes.Buffer{}
+	code := ParseAndRun(ioutil.Discard, stdout, nil, []string{"-d", "testdata", "testverbose"})
+	if code != 0 {
+		t.Fatal("unexpected code", code)
+	}
 
+	if stdout.String() != "" {
+		t.Fatalf("expected no output, but got %s", stdout.String())
+	}
 }
 
 func TestList(t *testing.T) {

mage/template.go

@@ -102,7 +102,8 @@ func main() {
 	_ = handleError
 
 	log.SetFlags(0)
-	if os.Getenv("MAGEFILE_VERBOSE") == "" {
+	verbose, _ := strconv.ParseBool(os.Getenv("MAGEFILE_VERBOSE"))
+	if !verbose {
 		log.SetOutput(ioutil.Discard)
 	}
 	logger := log.New(os.Stderr, "", 0)
@@ -163,8 +164,6 @@ func main() {
 				os.Exit(1)
 		}	
 	}
-	// to avoid unused import
-	_ = strconv.ParseBool
 	if len(os.Args) < 2 {
 	{{- if .Default}}
 		ignore, _ := strconv.ParseBool(os.Getenv("MAGEFILE_IGNOREDEFAULT"))
@@ -196,7 +195,7 @@ func main() {
 		switch strings.ToLower(target) {
 		{{range .Funcs }}
 		case "{{lower .TemplateName}}":
-			if os.Getenv("MAGEFILE_VERBOSE") != "" {
+			if verbose {
 				logger.Println("Running target:", "{{.TemplateName}}")
 			}
 			{{.TemplateString}}