Merge remote-tracking branch 'origin/main' into mostynb-report_source_of_parse_errors

flag.go

@@ -5,7 +5,6 @@ import (
 	"flag"
 	"fmt"
 	"io/ioutil"
-	"reflect"
 	"regexp"
 	"runtime"
 	"strconv"
@@ -117,6 +116,12 @@ type DocGenerationFlag interface {
 	// GetValue returns the flags value as string representation and an empty
 	// string if the flag takes no value at all.
 	GetValue() string
+
+	// GetDefaultText returns the default text for this flag
+	GetDefaultText() string
+
+	// GetEnvVars returns the env vars for this flag
+	GetEnvVars() []string
 }
 
 // VisibleFlag is an interface that allows to check if a flag is visible
@@ -238,7 +243,7 @@ func prefixedNames(names []string, placeholder string) string {
 
 func withEnvHint(envVars []string, str string) string {
 	envText := ""
-	if envVars != nil && len(envVars) > 0 {
+	if len(envVars) > 0 {
 		prefix := "$"
 		suffix := ""
 		sep := ", $"
@@ -267,17 +272,6 @@ func flagNames(name string, aliases []string) []string {
 	return ret
 }
 
-func flagStringSliceField(f Flag, name string) []string {
-	fv := flagValue(f)
-	field := fv.FieldByName(name)
-
-	if field.IsValid() {
-		return field.Interface().([]string)
-	}
-
-	return []string{}
-}
-
 func withFileHint(filePath, str string) string {
 	fileText := ""
 	if filePath != "" {
@@ -286,68 +280,34 @@ func withFileHint(filePath, str string) string {
 	return str + fileText
 }
 
-func flagValue(f Flag) reflect.Value {
-	fv := reflect.ValueOf(f)
-	for fv.Kind() == reflect.Ptr {
-		fv = reflect.Indirect(fv)
-	}
-	return fv
-}
-
 func formatDefault(format string) string {
 	return " (default: " + format + ")"
 }
 
 func stringifyFlag(f Flag) string {
-	fv := flagValue(f)
-
-	switch f := f.(type) {
-	case *IntSliceFlag:
-		return withEnvHint(flagStringSliceField(f, "EnvVars"),
-			stringifyIntSliceFlag(f))
-	case *Int64SliceFlag:
-		return withEnvHint(flagStringSliceField(f, "EnvVars"),
-			stringifyInt64SliceFlag(f))
-	case *Float64SliceFlag:
-		return withEnvHint(flagStringSliceField(f, "EnvVars"),
-			stringifyFloat64SliceFlag(f))
-	case *StringSliceFlag:
-		return withEnvHint(flagStringSliceField(f, "EnvVars"),
-			stringifyStringSliceFlag(f))
+	// enforce DocGeneration interface on flags to avoid reflection
+	df, ok := f.(DocGenerationFlag)
+	if !ok {
+		return ""
 	}
 
-	placeholder, usage := unquoteUsage(fv.FieldByName("Usage").String())
-
-	needsPlaceholder := false
-	defaultValueString := ""
-	val := fv.FieldByName("Value")
-	if val.IsValid() {
-		needsPlaceholder = val.Kind() != reflect.Bool
-		defaultValueString = fmt.Sprintf(formatDefault("%v"), val.Interface())
-
-		if val.Kind() == reflect.String && val.String() != "" {
-			defaultValueString = fmt.Sprintf(formatDefault("%q"), val.String())
-		}
-	}
-
-	helpText := fv.FieldByName("DefaultText")
-	if helpText.IsValid() && helpText.String() != "" {
-		needsPlaceholder = val.Kind() != reflect.Bool
-		defaultValueString = fmt.Sprintf(formatDefault("%s"), helpText.String())
-	}
-
-	if defaultValueString == formatDefault("") {
-		defaultValueString = ""
-	}
+	placeholder, usage := unquoteUsage(df.GetUsage())
+	needsPlaceholder := df.TakesValue()
 
 	if needsPlaceholder && placeholder == "" {
 		placeholder = defaultPlaceholder
 	}
 
+	defaultValueString := ""
+
+	if s := df.GetDefaultText(); s != "" {
+		defaultValueString = fmt.Sprintf(formatDefault("%s"), s)
+	}
+
 	usageWithDefault := strings.TrimSpace(usage + defaultValueString)
 
-	return withEnvHint(flagStringSliceField(f, "EnvVars"),
-		fmt.Sprintf("%s\t%s", prefixedNames(f.Names(), placeholder), usageWithDefault))
+	return withEnvHint(df.GetEnvVars(),
+		fmt.Sprintf("%s\t%s", prefixedNames(df.Names(), placeholder), usageWithDefault))
 }
 
 func stringifyIntSliceFlag(f *IntSliceFlag) string {
@@ -445,3 +405,7 @@ func flagFromEnvOrFile(envVars []string, filePath string) (value string, fromWhe
 	}
 	return "", "", false
 }
+
+func flagSplitMultiValues(val string) []string {
+	return strings.Split(val, ",")
+}