fixup! Add assertions

Author: jfreden

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/transport/CrossClusterApiKeySigner.java

@@ -69,7 +69,7 @@ public void loadSigningConfig(String clusterAlias, @Nullable Settings settings,
                 settings,
                 updateSecureSettings
             );
-
+            assert effectiveSettings != null : "Signing config settings must not be null";
             logger.trace("Loading signing config for [{}] with settings [{}]", clusterAlias, effectiveSettings);
 
             SigningConfig signingConfig = new SigningConfig(null, null, effectiveSettings);
@@ -109,7 +109,6 @@ public X509CertificateSignature sign(String clusterAlias, String... headers) {
             return null;
         }
         var keyPair = signingConfig.keyPair();
-
         try {
             String algorithm = keyPair.signatureAlgorithm();
             Signature signature = Signature.getInstance(algorithm);
@@ -195,6 +194,8 @@ private X509KeyPair buildKeyPair(SslKeyConfig keyConfig) {
     }
 
     private X509KeyPair buildKeyPair(SslKeyConfig keyConfig, String alias) {
+        assert alias != null;
+
         final X509KeyManager keyManager = keyConfig.createKeyManager();
         if (keyManager == null) {
             return null;
@@ -233,8 +234,8 @@ private static String calculateFingerprint(X509Certificate certificate) {
     private record X509KeyPair(X509Certificate certificate, PrivateKey privateKey, String signatureAlgorithm, String fingerprint) {
         X509KeyPair(X509Certificate certificate, PrivateKey privateKey) {
             this(
-                certificate,
-                privateKey,
+                Objects.requireNonNull(certificate),
+                Objects.requireNonNull(privateKey),
                 Optional.ofNullable(SIGNATURE_ALGORITHM_BY_TYPE.get(privateKey.getAlgorithm()))
                     .orElseThrow(
                         () -> new IllegalArgumentException(
@@ -246,6 +247,6 @@ private record X509KeyPair(X509Certificate certificate, PrivateKey privateKey, S
         }
     }
 
-    private record SigningConfig(@Nullable X509KeyPair keyPair, @Nullable Collection<Path> dependentFiles, @Nullable Settings settings) {}
+    private record SigningConfig(@Nullable X509KeyPair keyPair, @Nullable Collection<Path> dependentFiles, Settings settings) {}
 
 }