From 791ff1029a6c82b7be464f766d5e06f242c05651 Mon Sep 17 00:00:00 2001
From: Gerardo Rodriguez <g@rodrz.com>
Date: Wed, 9 Sep 2026 21:46:50 -0400
Subject: [PATCH] Return errors from failed FCM registration

---
 gcm.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/gcm.go b/gcm.go
index 6d83a02..1acd3fe 100644
--- a/gcm.go
+++ b/gcm.go
@@ -72,7 +72,15 @@ func RegisterGCM(ctx context.Context, authorizationEntity string, creds GCMCrede
 	if err != nil {
 		return nil, errors.Wrap(err, "parse GCM register URL")
 	}
+	if errorCode := subscription.Get("Error"); errorCode != "" {
+		return nil, errors.Errorf("GCM registration failed: %s", errorCode)
+	} else if res.StatusCode != http.StatusOK {
+		return nil, errors.Errorf("GCM registration failed with HTTP %d", res.StatusCode)
+	}
 	token := subscription.Get("token")
+	if token == "" {
+		return nil, errors.New("GCM registration returned an empty token")
+	}
 
 	return &FCMCredentials{
 		GCM:   creds,