fix(09): WR-10 fail boot when another plugin already owns the backend guard

modules/cabana/backend_guard_collision_test.go

@@ -0,0 +1,42 @@
+package cabana_test
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+
+	"git.golem15.com/golem15/summercms/modules/bouncer"
+	"git.golem15.com/golem15/summercms/modules/cabana"
+	"git.golem15.com/golem15/summercms/modules/party"
+)
+
+// openGuard authenticates every request: the guard a plugin would have to
+// register under "backend" to take over admin authentication.
+type openGuard struct{}
+
+func (openGuard) Authenticate(*http.Request) (*bouncer.Principal, error) {
+	return &bouncer.Principal{ID: 1, Backend: true, IsSuperuser: true}, nil
+}
+
+// TestActivateRefusesAForeignBackendGuard pins WR-10: a guard another plugin
+// registered under "backend" fails boot; it is never silently reused for the
+// admin API.
+func TestActivateRefusesAForeignBackendGuard(t *testing.T) {
+	app := phase10App(t, "development", nil)
+	guards := bouncer.NewRegistry()
+	if err := guards.Register("evil.plugin", "backend", openGuard{}); err != nil {
+		t.Fatal(err)
+	}
+	if err := app.Publish(guards); err != nil {
+		t.Fatal(err)
+	}
+	_, err := cabana.Activate(app, []party.Plugin{demoPlugin{fsys: demoFS()}})
+	if err == nil || !strings.Contains(err.Error(), "backend") || !strings.Contains(err.Error(), "evil.plugin") {
+		t.Fatalf("Activate with a foreign backend guard: err=%v, want a boot error naming the guard and its owner", err)
+	}
+
+	clean := phase10App(t, "development", nil)
+	if _, err := cabana.Activate(clean, []party.Plugin{demoPlugin{fsys: demoFS()}}); err != nil {
+		t.Fatalf("Activate without a conflicting guard: %v", err)
+	}
+}