Do not serialize null properties in the management model

* Ignore null values in JSON output

* This may have an impact on existing client, but it is not
  likely to be substantial because normally absent properties
  should be treated the same as having `null` values.

* This change enables adding new optional fields to the
  Management API while maintaining backward compatibility in
  the future: New properties will not be exposed to clients
  unless a value for them in explicitly set.

Author: dimas-b

api/management-model/build.gradle.kts

@@ -56,6 +56,10 @@ openApiGenerate {
   additionalProperties.put("apiNamePrefix", "Polaris")
   additionalProperties.put("apiNameSuffix", "Api")
   additionalProperties.put("metricsPrefix", "polaris")
+  additionalProperties.put(
+    "additionalModelTypeAnnotations",
+    "@com.fasterxml.jackson.annotation.JsonInclude(com.fasterxml.jackson.annotation.JsonInclude.Include.NON_NULL)",
+  )
   serverVariables = mapOf("basePath" to "api/v1")
 }
 

api/management-model/src/test/java/org/apache/polaris/core/admin/model/CatalogSerializationTest.java

@@ -66,14 +66,8 @@ public void testJsonFormat() throws JsonProcessingException {
             "{\"type\":\"INTERNAL\","
                 + "\"name\":\"test-catalog\","
                 + "\"properties\":{\"default-base-location\":\"s3://test/\"},"
-                + "\"createTimestamp\":null,"
-                + "\"lastUpdateTimestamp\":null,"
-                + "\"entityVersion\":null,"
                 + "\"storageConfigInfo\":{"
                 + "\"roleArn\":\"arn:aws:iam::123456789012:role/test-role\","
-                + "\"externalId\":null,"
-                + "\"userArn\":null,"
-                + "\"region\":null,"
                 + "\"storageType\":\"S3\","
                 + "\"allowedLocations\":[]"
                 + "}}");