feat: add URL flag type with net/url support

url.go

@@ -0,0 +1,88 @@
+package pflag
+
+import (
+	"fmt"
+	"net/url"
+)
+
+// -- url.Value
+type urlValue struct {
+	value   *url.URL
+	changed bool
+}
+
+func newURLValue(val *url.URL, p *url.URL) *urlValue {
+	uv := new(urlValue)
+	uv.value = p
+	*uv.value = *val
+	return uv
+}
+
+func (u *urlValue) Set(s string) error {
+	v, err := url.Parse(s)
+	if err != nil {
+		return fmt.Errorf("failed to parse URL: %w", err)
+	}
+	*u.value = *v
+	u.changed = true
+	return nil
+}
+
+func (u *urlValue) Type() string {
+	return "url"
+}
+
+func (u *urlValue) String() string {
+	if u.value == nil {
+		return ""
+	}
+	return u.value.String()
+}
+
+// URLVar defines a url.URL flag with specified name, default value, and usage string.
+func (f *FlagSet) URLVar(p *url.URL, name string, value url.URL, usage string) {
+	f.VarP(newURLValue(&value, p), name, "", usage)
+}
+
+// URLVarP is like URLVar, but accepts a shorthand letter.
+func (f *FlagSet) URLVarP(p *url.URL, name, shorthand string, value url.URL, usage string) {
+	f.VarP(newURLValue(&value, p), name, shorthand, usage)
+}
+
+// URL defines a url.URL flag with specified name, default value, and usage string.
+func (f *FlagSet) URL(name string, value url.URL, usage string) *url.URL {
+	p := new(url.URL)
+	f.URLVarP(p, name, "", value, usage)
+	return p
+}
+
+// URLP is like URL, but accepts a shorthand letter.
+func (f *FlagSet) URLP(name, shorthand string, value url.URL, usage string) *url.URL {
+	p := new(url.URL)
+	f.URLVarP(p, name, shorthand, value, usage)
+	return p
+}
+
+// URLVar defines a url.URL flag with specified name, default value, and usage string.
+func URLVar(p *url.URL, name string, value url.URL, usage string) {
+	CommandLine.VarP(newURLValue(&value, p), name, "", usage)
+}
+
+// URLVarP is like URLVar, but accepts a shorthand letter.
+func URLVarP(p *url.URL, name, shorthand string, value url.URL, usage string) {
+	CommandLine.VarP(newURLValue(&value, p), name, shorthand, usage)
+}
+
+// URL defines a url.URL flag with specified name, default value, and usage string.
+func URL(name string, value url.URL, usage string) *url.URL {
+	p := new(url.URL)
+	CommandLine.URLVarP(p, name, "", value, usage)
+	return p
+}
+
+// URLP is like URL, but accepts a shorthand letter.
+func URLP(name, shorthand string, value url.URL, usage string) *url.URL {
+	p := new(url.URL)
+	CommandLine.URLVarP(p, name, shorthand, value, usage)
+	return p
+}

url_test.go

@@ -0,0 +1,62 @@
+package pflag
+
+import (
+	"net/url"
+	"testing"
+)
+
+func TestURL(t *testing.T) {
+	fs := NewFlagSet("test", ContinueOnError)
+	u := fs.URL("url", url.URL{Scheme: "https", Host: "example.com"}, "test url flag")
+	args := []string{"--url", "https://go.dev/pkg/net/url/"}
+	if err := fs.Parse(args); err != nil {
+		t.Fatal(err)
+	}
+	if u.String() != "https://go.dev/pkg/net/url/" {
+		t.Errorf("expected https://go.dev/pkg/net/url/, got %s", u.String())
+	}
+}
+
+func TestURLDefault(t *testing.T) {
+	fs := NewFlagSet("test", ContinueOnError)
+	u := fs.URL("url", url.URL{Scheme: "https", Host: "example.com"}, "test url flag")
+	if err := fs.Parse([]string{}); err != nil {
+		t.Fatal(err)
+	}
+	if u.String() != "https://example.com" {
+		t.Errorf("expected https://example.com, got %s", u.String())
+	}
+}
+
+func TestURLInvalid(t *testing.T) {
+	fs := NewFlagSet("test", ContinueOnError)
+	fs.URL("url", url.URL{}, "test url flag")
+	args := []string{"--url", "://invalid"}
+	if err := fs.Parse(args); err == nil {
+		t.Error("expected error for invalid URL, got nil")
+	}
+}
+
+func TestURLP(t *testing.T) {
+	fs := NewFlagSet("test", ContinueOnError)
+	u := fs.URLP("url", "u", url.URL{}, "test url flag")
+	args := []string{"-u", "https://example.com/path"}
+	if err := fs.Parse(args); err != nil {
+		t.Fatal(err)
+	}
+	if u.String() != "https://example.com/path" {
+		t.Errorf("expected https://example.com/path, got %s", u.String())
+	}
+}
+
+func TestURLChanged(t *testing.T) {
+	fs := NewFlagSet("test", ContinueOnError)
+	fs.URL("url", url.URL{}, "test url flag")
+	args := []string{"--url", "https://changed.com"}
+	if err := fs.Parse(args); err != nil {
+		t.Fatal(err)
+	}
+	if !fs.Lookup("url").Changed {
+		t.Error("expected Changed to be true")
+	}
+}