feat: expose ValueFormatter option through HelpOptions for custom HelpPrinters (#563)

Author: mpeyper

context.go

@@ -883,6 +883,11 @@ func (c *Context) Run(binds ...any) (err error) {
 func (c *Context) PrintUsage(summary bool) error {
 	options := c.helpOptions
 	options.Summary = summary
+	return c.printHelp(options)
+}
+
+func (c *Context) printHelp(options HelpOptions) error {
+	options.ValueFormatter = c.Kong.helpFormatter
 	return c.help(options, c)
 }
 

help.go

@@ -21,7 +21,7 @@ func (h helpFlag) IgnoreDefault() {}
 func (h helpFlag) BeforeReset(ctx *Context) error {
 	options := ctx.Kong.helpOptions
 	options.Summary = false
-	err := ctx.Kong.help(options, ctx)
+	err := ctx.printHelp(options)
 	if err != nil {
 		return err
 	}
@@ -58,6 +58,9 @@ type HelpOptions struct {
 	// If this is set to a non-positive number, the terminal width is used; otherwise,
 	// the min of this value or the terminal width is used.
 	WrapUpperBound int
+
+	// ValueFormatter is used to format the help text of flags and positional arguments.
+	ValueFormatter HelpValueFormatter
 }
 
 // Apply options to Kong as a configuration option.
@@ -365,10 +368,9 @@ func printCommandSummary(w *helpWriter, cmd *Command) {
 }
 
 type helpWriter struct {
-	indent        string
-	width         int
-	lines         *[]string
-	helpFormatter HelpValueFormatter
+	indent string
+	width  int
+	lines  *[]string
 	HelpOptions
 }
 
@@ -379,11 +381,10 @@ func newHelpWriter(ctx *Context, options HelpOptions) *helpWriter {
 		wrapWidth = options.WrapUpperBound
 	}
 	w := &helpWriter{
-		indent:        "",
-		width:         wrapWidth,
-		lines:         &lines,
-		helpFormatter: ctx.Kong.helpFormatter,
-		HelpOptions:   options,
+		indent:      "",
+		width:       wrapWidth,
+		lines:       &lines,
+		HelpOptions: options,
 	}
 	return w
 }
@@ -398,7 +399,7 @@ func (h *helpWriter) Print(text string) {
 
 // Indent returns a new helpWriter indented by two characters.
 func (h *helpWriter) Indent() *helpWriter {
-	return &helpWriter{indent: h.indent + "  ", lines: h.lines, width: h.width - 2, HelpOptions: h.HelpOptions, helpFormatter: h.helpFormatter}
+	return &helpWriter{indent: h.indent + "  ", lines: h.lines, width: h.width - 2, HelpOptions: h.HelpOptions}
 }
 
 func (h *helpWriter) String() string {
@@ -426,7 +427,7 @@ func (h *helpWriter) Wrap(text string) {
 func writePositionals(w *helpWriter, args []*Positional) {
 	rows := [][2]string{}
 	for _, arg := range args {
-		rows = append(rows, [2]string{arg.Summary(), w.helpFormatter(arg)})
+		rows = append(rows, [2]string{arg.Summary(), w.HelpOptions.ValueFormatter(arg)})
 	}
 	writeTwoColumns(w, rows)
 }
@@ -448,7 +449,7 @@ func writeFlags(w *helpWriter, groups [][]*Flag) {
 		}
 		for _, flag := range group {
 			if !flag.Hidden {
-				rows = append(rows, [2]string{formatFlag(haveShort, flag), w.helpFormatter(flag.Value)})
+				rows = append(rows, [2]string{formatFlag(haveShort, flag), w.HelpOptions.ValueFormatter(flag.Value)})
 			}
 		}
 	}

kong.go

@@ -472,7 +472,7 @@ func (k *Kong) FatalIfErrorf(err error, args ...any) {
 	if errors.As(err, &parseErr) {
 		switch k.usageOnError {
 		case fullUsage:
-			_ = k.help(k.helpOptions, parseErr.Context)
+			_ = parseErr.Context.printHelp(k.helpOptions)
 			fmt.Fprintln(k.Stdout)
 		case shortUsage:
 			_ = k.shortHelp(k.helpOptions, parseErr.Context)