vector: cover the identity object in s3vectors auth (#12162)

vector: cover the identity object in the s3vectors auth context

The auth middleware must carry the resolved identity object — only
the name survives otherwise and authorization loses actions, account,
and claims.

weed/s3api/s3vectors/auth_test.go

@@ -0,0 +1,37 @@
+package s3vectors
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/seaweedfs/seaweedfs/weed/s3api"
+	"github.com/seaweedfs/seaweedfs/weed/s3api/s3_constants"
+	"github.com/seaweedfs/seaweedfs/weed/s3api/s3err"
+)
+
+type fakeAuthenticator struct {
+	identity *s3api.Identity
+}
+
+func (f *fakeAuthenticator) AuthenticateRequest(r *http.Request) (string, interface{}, s3err.ErrorCode) {
+	return f.identity.Name, f.identity, s3err.ErrNone
+}
+
+func (f *fakeAuthenticator) DefaultAllow() bool { return true }
+
+// The authenticated identity object must ride the request context — only the
+// name survives otherwise, and downstream authorization loses actions,
+// account, and claims.
+func TestAuthKeepsIdentityObject(t *testing.T) {
+	want := &s3api.Identity{Name: "alice", Actions: []s3api.Action{"Admin"}}
+	s := &Server{authenticator: &fakeAuthenticator{identity: want}}
+	var got interface{}
+	h := s.Auth(func(w http.ResponseWriter, r *http.Request) {
+		got = s3_constants.GetIdentityFromContext(r)
+	})
+	h(httptest.NewRecorder(), httptest.NewRequest(http.MethodPost, "/", nil))
+	if got != interface{}(want) {
+		t.Fatalf("identity object missing from context: %v", got)
+	}
+}