From: rpothier <rpothier@cisco.com>
Date: Fri, 9 Oct 2020 15:52:03 -0400
Subject: Add IPNetSlice and unit tests (#170)

Origin: backport, https://github.com/spf13/pflag/commit/85dd5c8
---
 ipnet_slice.go      | 147 ++++++++++++++++++++++++++++++++
 ipnet_slice_test.go | 239 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 386 insertions(+)
 create mode 100644 ipnet_slice.go
 create mode 100644 ipnet_slice_test.go

diff --git a/ipnet_slice.go b/ipnet_slice.go
new file mode 100644
index 0000000..6b541aa
--- /dev/null
+++ b/ipnet_slice.go
@@ -0,0 +1,147 @@
+package pflag
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"strings"
+)
+
+// -- ipNetSlice Value
+type ipNetSliceValue struct {
+	value   *[]net.IPNet
+	changed bool
+}
+
+func newIPNetSliceValue(val []net.IPNet, p *[]net.IPNet) *ipNetSliceValue {
+	ipnsv := new(ipNetSliceValue)
+	ipnsv.value = p
+	*ipnsv.value = val
+	return ipnsv
+}
+
+// Set converts, and assigns, the comma-separated IPNet argument string representation as the []net.IPNet value of this flag.
+// If Set is called on a flag that already has a []net.IPNet assigned, the newly converted values will be appended.
+func (s *ipNetSliceValue) Set(val string) error {
+
+	// remove all quote characters
+	rmQuote := strings.NewReplacer(`"`, "", `'`, "", "`", "")
+
+	// read flag arguments with CSV parser
+	ipNetStrSlice, err := readAsCSV(rmQuote.Replace(val))
+	if err != nil && err != io.EOF {
+		return err
+	}
+
+	// parse ip values into slice
+	out := make([]net.IPNet, 0, len(ipNetStrSlice))
+	for _, ipNetStr := range ipNetStrSlice {
+		_, n, err := net.ParseCIDR(strings.TrimSpace(ipNetStr))
+		if err != nil {
+			return fmt.Errorf("invalid string being converted to CIDR: %s", ipNetStr)
+		}
+		out = append(out, *n)
+	}
+
+	if !s.changed {
+		*s.value = out
+	} else {
+		*s.value = append(*s.value, out...)
+	}
+
+	s.changed = true
+
+	return nil
+}
+
+// Type returns a string that uniquely represents this flag's type.
+func (s *ipNetSliceValue) Type() string {
+	return "ipNetSlice"
+}
+
+// String defines a "native" format for this net.IPNet slice flag value.
+func (s *ipNetSliceValue) String() string {
+
+	ipNetStrSlice := make([]string, len(*s.value))
+	for i, n := range *s.value {
+		ipNetStrSlice[i] = n.String()
+	}
+
+	out, _ := writeAsCSV(ipNetStrSlice)
+	return "[" + out + "]"
+}
+
+func ipNetSliceConv(val string) (interface{}, error) {
+	val = strings.Trim(val, "[]")
+	// Emtpy string would cause a slice with one (empty) entry
+	if len(val) == 0 {
+		return []net.IPNet{}, nil
+	}
+	ss := strings.Split(val, ",")
+	out := make([]net.IPNet, len(ss))
+	for i, sval := range ss {
+		_, n, err := net.ParseCIDR(strings.TrimSpace(sval))
+		if err != nil {
+			return nil, fmt.Errorf("invalid string being converted to CIDR: %s", sval)
+		}
+		out[i] = *n
+	}
+	return out, nil
+}
+
+// GetIPNetSlice returns the []net.IPNet value of a flag with the given name
+func (f *FlagSet) GetIPNetSlice(name string) ([]net.IPNet, error) {
+	val, err := f.getFlagType(name, "ipNetSlice", ipNetSliceConv)
+	if err != nil {
+		return []net.IPNet{}, err
+	}
+	return val.([]net.IPNet), nil
+}
+
+// IPNetSliceVar defines a ipNetSlice flag with specified name, default value, and usage string.
+// The argument p points to a []net.IPNet variable in which to store the value of the flag.
+func (f *FlagSet) IPNetSliceVar(p *[]net.IPNet, name string, value []net.IPNet, usage string) {
+	f.VarP(newIPNetSliceValue(value, p), name, "", usage)
+}
+
+// IPNetSliceVarP is like IPNetSliceVar, but accepts a shorthand letter that can be used after a single dash.
+func (f *FlagSet) IPNetSliceVarP(p *[]net.IPNet, name, shorthand string, value []net.IPNet, usage string) {
+	f.VarP(newIPNetSliceValue(value, p), name, shorthand, usage)
+}
+
+// IPNetSliceVar defines a []net.IPNet flag with specified name, default value, and usage string.
+// The argument p points to a []net.IPNet variable in which to store the value of the flag.
+func IPNetSliceVar(p *[]net.IPNet, name string, value []net.IPNet, usage string) {
+	CommandLine.VarP(newIPNetSliceValue(value, p), name, "", usage)
+}
+
+// IPNetSliceVarP is like IPNetSliceVar, but accepts a shorthand letter that can be used after a single dash.
+func IPNetSliceVarP(p *[]net.IPNet, name, shorthand string, value []net.IPNet, usage string) {
+	CommandLine.VarP(newIPNetSliceValue(value, p), name, shorthand, usage)
+}
+
+// IPNetSlice defines a []net.IPNet flag with specified name, default value, and usage string.
+// The return value is the address of a []net.IPNet variable that stores the value of that flag.
+func (f *FlagSet) IPNetSlice(name string, value []net.IPNet, usage string) *[]net.IPNet {
+	p := []net.IPNet{}
+	f.IPNetSliceVarP(&p, name, "", value, usage)
+	return &p
+}
+
+// IPNetSliceP is like IPNetSlice, but accepts a shorthand letter that can be used after a single dash.
+func (f *FlagSet) IPNetSliceP(name, shorthand string, value []net.IPNet, usage string) *[]net.IPNet {
+	p := []net.IPNet{}
+	f.IPNetSliceVarP(&p, name, shorthand, value, usage)
+	return &p
+}
+
+// IPNetSlice defines a []net.IPNet flag with specified name, default value, and usage string.
+// The return value is the address of a []net.IP variable that stores the value of the flag.
+func IPNetSlice(name string, value []net.IPNet, usage string) *[]net.IPNet {
+	return CommandLine.IPNetSliceP(name, "", value, usage)
+}
+
+// IPNetSliceP is like IPNetSlice, but accepts a shorthand letter that can be used after a single dash.
+func IPNetSliceP(name, shorthand string, value []net.IPNet, usage string) *[]net.IPNet {
+	return CommandLine.IPNetSliceP(name, shorthand, value, usage)
+}
diff --git a/ipnet_slice_test.go b/ipnet_slice_test.go
new file mode 100644
index 0000000..11644c5
--- /dev/null
+++ b/ipnet_slice_test.go
@@ -0,0 +1,239 @@
+package pflag
+
+import (
+	"fmt"
+	"net"
+	"strings"
+	"testing"
+)
+
+// Helper function to set static slices
+func getCIDR(ip net.IP, cidr *net.IPNet, err error) net.IPNet {
+	return *cidr
+}
+
+func equalCIDR(c1 net.IPNet, c2 net.IPNet) bool {
+	if c1.String() == c2.String() {
+		return true
+	}
+	return false
+}
+
+func setUpIPNetFlagSet(ipsp *[]net.IPNet) *FlagSet {
+	f := NewFlagSet("test", ContinueOnError)
+	f.IPNetSliceVar(ipsp, "cidrs", []net.IPNet{}, "Command separated list!")
+	return f
+}
+
+func setUpIPNetFlagSetWithDefault(ipsp *[]net.IPNet) *FlagSet {
+	f := NewFlagSet("test", ContinueOnError)
+	f.IPNetSliceVar(ipsp, "cidrs",
+		[]net.IPNet{
+			getCIDR(net.ParseCIDR("192.168.1.1/16")),
+			getCIDR(net.ParseCIDR("fd00::/64")),
+		},
+		"Command separated list!")
+	return f
+}
+
+func TestEmptyIPNet(t *testing.T) {
+	var cidrs []net.IPNet
+	f := setUpIPNetFlagSet(&cidrs)
+	err := f.Parse([]string{})
+	if err != nil {
+		t.Fatal("expected no error; got", err)
+	}
+
+	getIPNet, err := f.GetIPNetSlice("cidrs")
+	if err != nil {
+		t.Fatal("got an error from GetIPNetSlice():", err)
+	}
+	if len(getIPNet) != 0 {
+		t.Fatalf("got ips %v with len=%d but expected length=0", getIPNet, len(getIPNet))
+	}
+}
+
+func TestIPNets(t *testing.T) {
+	var ips []net.IPNet
+	f := setUpIPNetFlagSet(&ips)
+
+	vals := []string{"192.168.1.1/24", "10.0.0.1/16", "fd00:0:0:0:0:0:0:2/64"}
+	arg := fmt.Sprintf("--cidrs=%s", strings.Join(vals, ","))
+	err := f.Parse([]string{arg})
+	if err != nil {
+		t.Fatal("expected no error; got", err)
+	}
+	for i, v := range ips {
+		if _, cidr, _ := net.ParseCIDR(vals[i]); cidr == nil {
+			t.Fatalf("invalid string being converted to CIDR: %s", vals[i])
+		} else if !equalCIDR(*cidr, v) {
+			t.Fatalf("expected ips[%d] to be %s but got: %s from GetIPSlice", i, vals[i], v)
+		}
+	}
+}
+
+func TestIPNetDefault(t *testing.T) {
+	var cidrs []net.IPNet
+	f := setUpIPNetFlagSetWithDefault(&cidrs)
+
+	vals := []string{"192.168.1.1/16", "fd00::/64"}
+	err := f.Parse([]string{})
+	if err != nil {
+		t.Fatal("expected no error; got", err)
+	}
+	for i, v := range cidrs {
+		if _, cidr, _ := net.ParseCIDR(vals[i]); cidr == nil {
+			t.Fatalf("invalid string being converted to CIDR: %s", vals[i])
+		} else if !equalCIDR(*cidr, v) {
+			t.Fatalf("expected cidrs[%d] to be %s but got: %s", i, vals[i], v)
+		}
+	}
+
+	getIPNet, err := f.GetIPNetSlice("cidrs")
+	if err != nil {
+		t.Fatal("got an error from GetIPNetSlice")
+	}
+	for i, v := range getIPNet {
+		if _, cidr, _ := net.ParseCIDR(vals[i]); cidr == nil {
+			t.Fatalf("invalid string being converted to CIDR: %s", vals[i])
+		} else if !equalCIDR(*cidr, v) {
+			t.Fatalf("expected cidrs[%d] to be %s but got: %s", i, vals[i], v)
+		}
+	}
+}
+
+func TestIPNetWithDefault(t *testing.T) {
+	var cidrs []net.IPNet
+	f := setUpIPNetFlagSetWithDefault(&cidrs)
+
+	vals := []string{"192.168.1.1/16", "fd00::/64"}
+	arg := fmt.Sprintf("--cidrs=%s", strings.Join(vals, ","))
+	err := f.Parse([]string{arg})
+	if err != nil {
+		t.Fatal("expected no error; got", err)
+	}
+	for i, v := range cidrs {
+		if _, cidr, _ := net.ParseCIDR(vals[i]); cidr == nil {
+			t.Fatalf("invalid string being converted to CIDR: %s", vals[i])
+		} else if !equalCIDR(*cidr, v) {
+			t.Fatalf("expected cidrs[%d] to be %s but got: %s", i, vals[i], v)
+		}
+	}
+
+	getIPNet, err := f.GetIPNetSlice("cidrs")
+	if err != nil {
+		t.Fatal("got an error from GetIPNetSlice")
+	}
+	for i, v := range getIPNet {
+		if _, cidr, _ := net.ParseCIDR(vals[i]); cidr == nil {
+			t.Fatalf("invalid string being converted to CIDR: %s", vals[i])
+		} else if !equalCIDR(*cidr, v) {
+			t.Fatalf("expected cidrs[%d] to be %s but got: %s", i, vals[i], v)
+		}
+	}
+}
+
+func TestIPNetCalledTwice(t *testing.T) {
+	var cidrs []net.IPNet
+	f := setUpIPNetFlagSet(&cidrs)
+
+	in := []string{"192.168.1.2/16,fd00::/64", "10.0.0.1/24"}
+
+	expected := []net.IPNet{
+		getCIDR(net.ParseCIDR("192.168.1.2/16")),
+		getCIDR(net.ParseCIDR("fd00::/64")),
+		getCIDR(net.ParseCIDR("10.0.0.1/24")),
+	}
+	argfmt := "--cidrs=%s"
+	arg1 := fmt.Sprintf(argfmt, in[0])
+	arg2 := fmt.Sprintf(argfmt, in[1])
+	err := f.Parse([]string{arg1, arg2})
+	if err != nil {
+		t.Fatal("expected no error; got", err)
+	}
+	for i, v := range cidrs {
+		if !equalCIDR(expected[i], v) {
+			t.Fatalf("expected cidrs[%d] to be %s but got: %s", i, expected[i], v)
+		}
+	}
+}
+
+func TestIPNetBadQuoting(t *testing.T) {
+
+	tests := []struct {
+		Want    []net.IPNet
+		FlagArg []string
+	}{
+		{
+			Want: []net.IPNet{
+				getCIDR(net.ParseCIDR("a4ab:61d:f03e:5d7d:fad7:d4c2:a1a5:568/128")),
+				getCIDR(net.ParseCIDR("203.107.49.208/32")),
+				getCIDR(net.ParseCIDR("14.57.204.90/32")),
+			},
+			FlagArg: []string{
+				"a4ab:61d:f03e:5d7d:fad7:d4c2:a1a5:568/128",
+				"203.107.49.208/32",
+				"14.57.204.90/32",
+			},
+		},
+		{
+			Want: []net.IPNet{
+				getCIDR(net.ParseCIDR("204.228.73.195/32")),
+				getCIDR(net.ParseCIDR("86.141.15.94/32")),
+			},
+			FlagArg: []string{
+				"204.228.73.195/32",
+				"86.141.15.94/32",
+			},
+		},
+		{
+			Want: []net.IPNet{
+				getCIDR(net.ParseCIDR("c70c:db36:3001:890f:c6ea:3f9b:7a39:cc3f/128")),
+				getCIDR(net.ParseCIDR("4d17:1d6e:e699:bd7a:88c5:5e7e:ac6a:4472/128")),
+			},
+			FlagArg: []string{
+				"c70c:db36:3001:890f:c6ea:3f9b:7a39:cc3f/128",
+				"4d17:1d6e:e699:bd7a:88c5:5e7e:ac6a:4472/128",
+			},
+		},
+		{
+			Want: []net.IPNet{
+				getCIDR(net.ParseCIDR("5170:f971:cfac:7be3:512a:af37:952c:bc33/128")),
+				getCIDR(net.ParseCIDR("93.21.145.140/32")),
+				getCIDR(net.ParseCIDR("2cac:61d3:c5ff:6caf:73e0:1b1a:c336:c1ca/128")),
+			},
+			FlagArg: []string{
+				" 5170:f971:cfac:7be3:512a:af37:952c:bc33/128  , 93.21.145.140/32     ",
+				"2cac:61d3:c5ff:6caf:73e0:1b1a:c336:c1ca/128",
+			},
+		},
+		{
+			Want: []net.IPNet{
+				getCIDR(net.ParseCIDR("2e5e:66b2:6441:848:5b74:76ea:574c:3a7b/128")),
+				getCIDR(net.ParseCIDR("2e5e:66b2:6441:848:5b74:76ea:574c:3a7b/128")),
+				getCIDR(net.ParseCIDR("2e5e:66b2:6441:848:5b74:76ea:574c:3a7b/128")),
+				getCIDR(net.ParseCIDR("2e5e:66b2:6441:848:5b74:76ea:574c:3a7b/128")),
+			},
+			FlagArg: []string{
+				`"2e5e:66b2:6441:848:5b74:76ea:574c:3a7b/128,        2e5e:66b2:6441:848:5b74:76ea:574c:3a7b/128,2e5e:66b2:6441:848:5b74:76ea:574c:3a7b/128     "`,
+				" 2e5e:66b2:6441:848:5b74:76ea:574c:3a7b/128"},
+		},
+	}
+
+	for i, test := range tests {
+
+		var cidrs []net.IPNet
+		f := setUpIPNetFlagSet(&cidrs)
+
+		if err := f.Parse([]string{fmt.Sprintf("--cidrs=%s", strings.Join(test.FlagArg, ","))}); err != nil {
+			t.Fatalf("flag parsing failed with error: %s\nparsing:\t%#v\nwant:\t\t%s",
+				err, test.FlagArg, test.Want[i])
+		}
+
+		for j, b := range cidrs {
+			if !equalCIDR(b, test.Want[j]) {
+				t.Fatalf("bad value parsed for test %d on net.IP %d:\nwant:\t%s\ngot:\t%s", i, j, test.Want[j], b)
+			}
+		}
+	}
+}