From: Kyle Lemons <kyle@kylelemons.net>
Date: Tue, 6 Aug 2013 06:48:19 +0000 (+1000)
Subject: flag: document the zero value of FlagSet
X-Git-Tag: go1.2rc2~770
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=321ede78e3fc432ff2f2ad5fb4babc4b45d82ed9;p=gostls13.git

flag: document the zero value of FlagSet

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12403043
---

diff --git a/src/pkg/flag/flag.go b/src/pkg/flag/flag.go
index bde055d3bd..18841e3a91 100644
--- a/src/pkg/flag/flag.go
+++ b/src/pkg/flag/flag.go
@@ -256,7 +256,8 @@ const (
 	PanicOnError
 )
 
-// A FlagSet represents a set of defined flags.
+// A FlagSet represents a set of defined flags.  The zero value of a FlagSet
+// has no name and has ContinueOnError error handling.
 type FlagSet struct {
 	// Usage is the function called when an error occurs while parsing flags.
 	// The field is a function (not a method) that may be changed to point to
@@ -391,7 +392,11 @@ func PrintDefaults() {
 
 // defaultUsage is the default function to print a usage message.
 func defaultUsage(f *FlagSet) {
-	fmt.Fprintf(f.out(), "Usage of %s:\n", f.name)
+	if f.name == "" {
+		fmt.Fprintf(f.out(), "Usage:\n")
+	} else {
+		fmt.Fprintf(f.out(), "Usage of %s:\n", f.name)
+	}
 	f.PrintDefaults()
 }
 
@@ -658,7 +663,12 @@ func (f *FlagSet) Var(value Value, name string, usage string) {
 	flag := &Flag{name, usage, value, value.String()}
 	_, alreadythere := f.formal[name]
 	if alreadythere {
-		msg := fmt.Sprintf("%s flag redefined: %s", f.name, name)
+		var msg string
+		if f.name == "" {
+			msg = fmt.Sprintf("flag redefined: %s", name)
+		} else {
+			msg = fmt.Sprintf("%s flag redefined: %s", f.name, name)
+		}
 		fmt.Fprintln(f.out(), msg)
 		panic(msg) // Happens only if flags are declared with identical names
 	}