From 8824ec2f84efc5232daca3cb5403690b695190eb Mon Sep 17 00:00:00 2001
From: Eric Paris <eparis@redhat.com>
Date: Tue, 7 Apr 2015 16:50:29 -0400
Subject: Ability to mark flags as deprecated

They will not show up in usage or help, but they will still work.
The usage message will print on os.Stderr any time the flag is set.
---
 flag_test.go | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

(limited to 'flag_test.go')

diff --git a/flag_test.go b/flag_test.go
index c4055ed..a1478e2 100644
--- a/flag_test.go
+++ b/flag_test.go
@@ -7,6 +7,7 @@ package pflag_test
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
 	"sort"
@@ -445,3 +446,74 @@ func TestTermination(t *testing.T) {
 		t.Errorf("expected argument %q got %q", arg2, f.Args()[1])
 	}
 }
+
+func TestDeprecatedFlagInDocs(t *testing.T) {
+	f := NewFlagSet("bob", ContinueOnError)
+	f.Bool("badflag", true, "always true")
+	f.MarkDeprecated("badflag", "use --good-flag instead")
+
+	out := new(bytes.Buffer)
+	f.SetOutput(out)
+	f.PrintDefaults()
+
+	if strings.Contains(out.String(), "badflag") {
+		t.Errorf("found deprecated flag in usage!")
+	}
+}
+
+func parseReturnStderr(t *testing.T, f *FlagSet, args []string) (string, error) {
+	oldStderr := os.Stderr
+	r, w, _ := os.Pipe()
+	os.Stderr = w
+
+	err := f.Parse(args)
+
+	outC := make(chan string)
+	// copy the output in a separate goroutine so printing can't block indefinitely
+	go func() {
+		var buf bytes.Buffer
+		io.Copy(&buf, r)
+		outC <- buf.String()
+	}()
+
+	w.Close()
+	os.Stderr = oldStderr
+	out := <-outC
+
+	return out, err
+}
+
+func TestDeprecatedFlagUsage(t *testing.T) {
+	f := NewFlagSet("bob", ContinueOnError)
+	f.Bool("badflag", true, "always true")
+	usageMsg := "use --good-flag instead"
+	f.MarkDeprecated("badflag", usageMsg)
+
+	args := []string{"--badflag"}
+	out, err := parseReturnStderr(t, f, args)
+	if err != nil {
+		t.Fatal("expected no error; got ", err)
+	}
+
+	if !strings.Contains(out, usageMsg) {
+		t.Errorf("usageMsg not printed when using a deprecated flag!")
+	}
+}
+
+func TestDeprecatedFlagUsageNormalized(t *testing.T) {
+	f := NewFlagSet("bob", ContinueOnError)
+	f.Bool("bad-double_flag", true, "always true")
+	f.SetWordSeparators([]string{"-", "_"})
+	usageMsg := "use --good-flag instead"
+	f.MarkDeprecated("bad_double-flag", usageMsg)
+
+	args := []string{"--bad_double_flag"}
+	out, err := parseReturnStderr(t, f, args)
+	if err != nil {
+		t.Fatal("expected no error; got ", err)
+	}
+
+	if !strings.Contains(out, usageMsg) {
+		t.Errorf("usageMsg not printed when using a deprecated flag!")
+	}
+}
-- 
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