feat(label): edit a label in a form without flags

label edit without flags on a terminal now opens a form with the label's
name, color, description and flags, like milestone edit and issue edit,
instead of failing; without a terminal it reports the shared "nothing to
edit" error. The help of issue and milestone close and reopen names its
commands without generating the text from the verb.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/label_options_test.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 	"testing"
 
+	"gitea.dev/tea/internal/terminal"
 	"github.com/stretchr/testify/require"
 )
 
@@ -193,3 +194,45 @@ func TestLabelCreatePicksAColorAndPrompts(t *testing.T) {
 	require.Equal(t, "From a prompt", created[1]["description"])
 	require.Equal(t, []string{"Label name", "Color (hex, e.g. d73a4a; empty = random):", "Description (optional):"}, prompt.asked)
 }
+
+// labelFormPrompter answers the label form with edit applied to the current values.
+type labelFormPrompter struct {
+	scriptedPrompter
+	heading string
+	edit    func(*terminal.LabelFormValues)
+}
+
+func (p *labelFormPrompter) EditLabel(_ context.Context, heading string, current terminal.LabelFormValues) (terminal.LabelFormValues, error) {
+	p.heading = heading
+	p.edit(&current)
+	return current, nil
+}
+
+func TestLabelEditFormStartsFromTheLabel(t *testing.T) {
+	var edited string
+	server := newAuthenticatedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.Method + " " + r.URL.Path {
+		case "GET /api/v1/repos/alice/project/labels":
+			if r.URL.Query().Get("page") != "1" {
+				_, _ = w.Write([]byte(`[]`))
+				return
+			}
+			_, _ = w.Write([]byte(`[{"id":11,"name":"bug","color":"ee0701","description":"Broken"}]`))
+		case "PATCH /api/v1/repos/alice/project/labels/11":
+			edited = requestFields(t, r, "name", "color", "description", "exclusive")
+			_, _ = w.Write([]byte(`{"id":11,"name":"defect"}`))
+		default:
+			t.Errorf("unexpected %s %s", r.Method, r.URL.Path)
+		}
+	}))
+	defer server.Close()
+	deps, _, _ := serverDeps(t, server.URL)
+	deps.Streams.InTTY, deps.Streams.ErrTTY = true, true
+	prompt := &labelFormPrompter{edit: func(v *terminal.LabelFormValues) { v.Name, v.Exclusive = "defect", true }}
+	deps.Prompter = prompt
+	require.NoError(t, Execute(context.Background(), deps, []string{"label", "edit", "bug", "-R", "alice/project"}))
+	require.Equal(t, `Editing label "bug" in alice/project`, prompt.heading)
+	require.Equal(t, "name=defect color=ee0701 description=Broken exclusive=true", edited)
+	deps.Streams.InTTY, deps.Streams.ErrTTY = false, false
+	require.ErrorIs(t, Execute(context.Background(), deps, []string{"label", "edit", "bug", "-R", "alice/project"}), errNothingToEdit)
+}