fix(milestone): address milestones by title or ID everywhere

milestone view v2.0 failed with "invalid resource number" although its
usage promised <id-or-name>, and issue create --milestone v1.0 failed
with a strconv error. Every milestone argument (view, edit, delete,
close, reopen, milestone issue add|remove|list) and issue create|edit
-m/--milestone now accept a title or an ID: a number is an ID first,
then a title; --by-name matches numeric titles only. --milestone-name
stays as a hidden name of --milestone, and issue edit gains
--remove-milestone (as does --milestone 0).

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

internal/app/milestone_names_test.go

@@ -6,6 +6,7 @@ package app
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"testing"
 
@@ -58,12 +59,13 @@ func TestMilestoneDeleteReturnsJSONSnapshotOnlyAfterSuccess(t *testing.T) {
 	calls := []string{}
 	fail := false
 	server := newAuthenticatedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		require.Equal(t, "/api/v1/repos/alice/project/milestones/9", r.URL.Path)
 		calls = append(calls, r.Method)
 		if r.Method == http.MethodGet {
-			_, _ = w.Write([]byte(`{"id":9,"title":"Release one","state":"open"}`))
+			require.Equal(t, "/api/v1/repos/alice/project/milestones", r.URL.Path)
+			writeMilestones(w, r, `[{"id":9,"title":"Release one","state":"open"}]`)
 			return
 		}
+		require.Equal(t, "/api/v1/repos/alice/project/milestones/9", r.URL.Path)
 		require.Equal(t, http.MethodDelete, r.Method)
 		if fail {
 			w.WriteHeader(403)
@@ -76,7 +78,7 @@ func TestMilestoneDeleteReturnsJSONSnapshotOnlyAfterSuccess(t *testing.T) {
 	args := []string{"milestone", "delete", "9", "-R", "alice/project", "--yes", "--json=id,title"}
 	require.NoError(t, Execute(context.Background(), deps, args))
 	require.JSONEq(t, `{"id":9,"title":"Release one"}`, out.String())
-	require.Equal(t, []string{"GET", "DELETE"}, calls)
+	require.Equal(t, []string{"GET", "GET", "DELETE"}, calls)
 	fail = true
 	out.Reset()
 	require.Error(t, Execute(context.Background(), deps, args))
@@ -113,5 +115,77 @@ func TestMilestoneIssueCommandsSelectByName(t *testing.T) {
 	require.NoError(t, Execute(context.Background(), deps, []string{"milestone", "issue", "add", "Release one", "3", "--by-name", "-R", "alice/project", "--json=number"}))
 	require.NotContains(t, calls, "GET /api/v1/repos/alice/project/milestones/9")
 	err := Execute(context.Background(), deps, []string{"milestone", "issue", "remove", " ", "3", "--by-name", "-R", "alice/project"})
-	require.ErrorContains(t, err, "milestone name cannot be empty")
+	require.ErrorContains(t, err, "milestone title or ID cannot be empty")
+}
+
+// writeMilestones answers a milestone listing with page, a JSON array, as its first and only page.
+func writeMilestones(w http.ResponseWriter, r *http.Request, page string) {
+	if r.URL.Query().Get("page") != "1" {
+		page = `[]`
+	}
+	_, _ = w.Write([]byte(page))
+}
+
+// payloadField returns the JSON request body's field name as text.
+func payloadField(t *testing.T, r *http.Request, name string) string {
+	t.Helper()
+	var payload map[string]any
+	require.NoError(t, json.NewDecoder(r.Body).Decode(&payload))
+	return fmt.Sprint(payload[name])
+}
+
+func TestMilestonesAcceptTitlesOrIDs(t *testing.T) {
+	var calls []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/milestones":
+			writeMilestones(w, r, `[{"id":3,"title":"v1.0","state":"open"},{"id":4,"title":"2026","state":"closed"},{"id":5,"title":"v2.0"}]`)
+		case "GET /api/v1/repos/alice/project/milestones/3", "GET /api/v1/repos/alice/project/milestones/4":
+			_, _ = w.Write([]byte(`{"id":3,"title":"v1.0","state":"open"}`))
+		case "PATCH /api/v1/repos/alice/project/milestones/3", "PATCH /api/v1/repos/alice/project/milestones/4":
+			calls = append(calls, r.Method+" "+r.URL.Path)
+			_, _ = w.Write([]byte(`{"id":3,"title":"v1.0","state":"closed"}`))
+		case "POST /api/v1/repos/alice/project/issues":
+			requirePayload(t, `{"title":"x","milestone":3}`, r.Body)
+			calls = append(calls, r.Method+" "+r.URL.Path)
+			_, _ = w.Write([]byte(`{"number":8}`))
+		case "PATCH /api/v1/repos/alice/project/issues/8":
+			calls = append(calls, r.Method+" "+r.URL.Path+" milestone="+payloadField(t, r, "milestone"))
+			_, _ = w.Write([]byte(`{"number":8}`))
+		default:
+			t.Errorf("unexpected %s %s", r.Method, r.URL.Path)
+			w.WriteHeader(http.StatusNotFound)
+		}
+	}))
+	defer server.Close()
+	deps, out, _ := serverDeps(t, server.URL)
+	run := func(args ...string) error {
+		return Execute(context.Background(), deps, append(args, "-R", "alice/project", "--json", "--yes"))
+	}
+	require.NoError(t, run("milestone", "view", "v1.0"))
+	require.Contains(t, out.String(), `"id":3`)
+	require.NoError(t, run("milestone", "close", "V1.0", "2026"))
+	require.NoError(t, run("issue", "create", "--title", "x", "-m", "v1.0"))
+	require.NoError(t, run("issue", "edit", "8", "--milestone-name", "3"))
+	require.NoError(t, run("issue", "edit", "8", "--remove-milestone"))
+	require.NoError(t, run("issue", "edit", "8", "--milestone", "0"))
+	require.Equal(t, []string{
+		"PATCH /api/v1/repos/alice/project/milestones/3",
+		"PATCH /api/v1/repos/alice/project/milestones/4",
+		"POST /api/v1/repos/alice/project/issues",
+		"PATCH /api/v1/repos/alice/project/issues/8 milestone=3",
+		"PATCH /api/v1/repos/alice/project/issues/8 milestone=0",
+		"PATCH /api/v1/repos/alice/project/issues/8 milestone=0",
+	}, calls)
+	for _, test := range []struct {
+		args []string
+		want string
+	}{
+		{[]string{"milestone", "view", "v9"}, `milestone "v9" not found in alice/project`},
+		{[]string{"milestone", "close", "v1.0", "3"}, "milestone 3 is selected more than once"},
+		{[]string{"issue", "create", "--title", "x", "--milestone", "nope"}, `milestone "nope" not found in alice/project`},
+	} {
+		require.ErrorContains(t, run(test.args...), test.want)
+	}
+	require.Len(t, calls, 6)
 }