fix(backups): leave the credentials Secret alone when BucketInfo has no endpoint

A BucketInfo without an endpoint differs from every credentials Secret
that has one, so the gate forced the bucket release on every throttle
window. That render cannot converge: an empty endpoint would be written
into the Secret every driver reads, and with the key absent the
template's trimPrefix fails and parks the release in Failed.

Assisted-by: LLM
Signed-off-by: Alexey Artamonov <aleksei.artamonov@aenix.io>

internal/backupcontroller/default_objects_gate.go

@@ -438,7 +438,9 @@ func (g *DefaultObjectsGate) Check(ctx context.Context) ([]string, bool, error)
 // writes for it. The COSI Secret being absent (the BucketAccess is being
 // re-granted) leaves nothing to compare against and is not staleness, and
 // neither is a source Secret the bucket chart does not render: the COSI Secret
-// itself (the projector accepts one) or one without the endpoint key.
+// itself (the projector accepts one) or one without the endpoint key. A
+// BucketInfo without an endpoint is not a target either: rendering from it
+// writes an empty endpoint, or fails the release when the key is absent.
 func (g *DefaultObjectsGate) staleCredentials(ctx context.Context, src *corev1.Secret) (string, error) {
 	if g.CredentialsCOSISecretName == "" || g.CredentialsHelmRelease.Name == "" || g.CredentialsHelmRelease.Namespace == "" {
 		return "", nil
@@ -466,7 +468,7 @@ func (g *DefaultObjectsGate) staleCredentials(ctx context.Context, src *corev1.S
 	}
 	want := strings.TrimPrefix(strings.TrimPrefix(info.Spec.SecretS3.Endpoint, "https://"), "http://")
 	have := string(src.Data["endpoint"])
-	if have == want {
+	if want == "" || have == want {
 		return "", nil
 	}
 	return fmt.Sprintf("Secret/%s (endpoint %q, COSI Secret has %q)", g.Config.SourceSecretName, have, want), nil

internal/backupcontroller/default_objects_gate_test.go

@@ -851,6 +851,10 @@ func TestCheckCredentialsEndpointComparison(t *testing.T) {
 		{"bare host", "s3.example.com", false},
 		{"other host", "https://s3.new.example.com", true},
 		{"other port", "https://s3.example.com:8443", true},
+		// A forced render from a BucketInfo with no endpoint would write an
+		// empty endpoint into the Secret every driver reads (or, with the key
+		// absent, fail the bucket release's render), never a working one.
+		{"no endpoint in BucketInfo", "", false},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			objs := append([]runtime.Object{helmReleaseObject(), credentialsHelmReleaseObject()}, allDefaultObjects()...)