Regression creating a namespace with "null" in "backlog_quota_map" causes a NullPointerException on 2.9.1, but not 2.9.0 or earlier

Describe the bug A stacktrace is raised when creating a namespace with a backlog quota map containing null, e.g.:

"backlog_quota_map": {"destination_storage": null, "message_age": {"policy": "producer_exception", "limitTime": 7200.0}}

To Reproduce

1. Start a standalone 2.9.1 broker, I used brew install apache-pulsar on an updated Homebrew on 12/21/21.
2. Create a new Namespace via the admin API. When POSTing to create it, set the backlog quota map field to the example value above.
3. See error

Expected behavior No error should be raised. Behavior should be consistent with prior broker versions.

Desktop (please complete the following information):

• OSX and Homebrew; MacOS 11.6.2.

Stacktrace

Response code: 500
URL: PUT http://127.0.0.1:8080/admin/v2/namespaces/chariot3/chariot_namespace_test_topic_str
Headers: Headers({'host': '127.0.0.1:8080', 'accept': '*/*', 'accept-encoding': 'gzip, deflate', 'connection': 'keep-alive', 'user-agent': 'python-httpx/0.21.1', 'content-length': '1938', 'content-type': 'application/json'})
Payload: b'{"anti_affinity_group": null, "backlog_quota_map": {"destination_storage": null, "message_age": {"policy": "producer_exception", "limitTime": 7200.0}}, "retention_policies": {"retentionTimeInMinutes": 720, "retentionSizeInMB": -1}, "persistence": {"bookkeeperEnsemble": 1, "bookkeeperWriteQuorum": 1, "bookkeeperAckQuorum": 1, "managedLedgerMaxMarkDeleteRate": 0}, "deduplicationEnabled": true, "deduplicationSnapshotIntervalSeconds": 60.0, "autoSubscriptionCreationOverride": {"allowAutoSubscriptionCreation": false}, "autoTopicCreationOverride": {"allowAutoTopicCreation": false, "defaultNumPartitions": 0, "topicType": "non-partitioned"}, "message_ttl_in_seconds": 0, "subscription_expiration_time_minutes": 0, "encryption_required": false, "inactive_topic_policies": {"maxInactiveDurationSeconds": -1, "inactiveTopicDeleteMode": "delete_when_no_subscriptions", "deleteWhileInactive": false}, "max_producers_per_topic": 100, "max_consumers_per_topic": 10, "max_consumers_per_subscription": 0, "max_unacked_messages_per_subscription": 10000, "max_unacked_messages_per_consumer": 100, "properties": {"chariot_primary": true, "chariot_topic_config": "{\\"consumer_groups\\": [{\\"name\\": \\"testsub\\", \\"type\\": 3}], \\"durability\\": 2, \\"max_consumers\\": 10, \\"max_message_size\\": 1024, \\"max_producers\\": 100, \\"payload\\": {\\"primitive_type\\": \\"STRING\\"}, \\"rate_limits\\": [{\\"actions\\": [2], \\"bytes\\": null, \\"messages\\": 1000, \\"period\\": 60.0}, {\\"actions\\": [1], \\"bytes\\": null, \\"messages\\": 500, \\"period\\": 60.0}, {\\"actions\\": [0], \\"bytes\\": null, \\"messages\\": 10, \\"period\\": 3600.0}], \\"send_timeout\\": 1.0, \\"team\\": \\"test_team\\", \\"thresholds\\": [{\\"actions\\": [1], \\"age\\": 43200.0, \\"kind\\": 0, \\"size\\": null}, {\\"actions\\": [3], \\"age\\": 7200.0, \\"kind\\": 1, \\"size\\": null}, {\\"actions\\": [0], \\"age\\": 1800.0, \\"kind\\": 1, \\"size\\": null}]}"}, "is_allow_auto_update_schema": true, "schema_validation_enforced": false}'

 --- An unexpected error occurred in the server ---

Message: com.fasterxml.jackson.databind.JsonMappingException: (was java.lang.NullPointerException) (through reference chain: org.apache.pulsar.common.policies.data.Policies["backlog_quota_map"]->java.util.LinkedHashMap["message_age"]->org.apache.pulsar.common.policies.data.impl.BacklogQuotaImpl["limit"])

Stacktrace:

org.apache.pulsar.metadata.api.MetadataStoreException: com.fasterxml.jackson.databind.JsonMappingException: (was java.lang.NullPointerException) (through reference chain: org.apache.pulsar.common.policies.data.Policies["backlog_quota_map"]->java.util.LinkedHashMap["message_age"]->org.apache.pulsar.common.policies.data.impl.BacklogQuotaImpl["limit"])
	at org.apache.pulsar.broker.resources.BaseResources.create(BaseResources.java:134)
	at org.apache.pulsar.broker.resources.NamespaceResources.createPolicies(NamespaceResources.java:75)
	at org.apache.pulsar.broker.admin.impl.NamespacesBase.internalCreateNamespace(NamespacesBase.java:146)
	at org.apache.pulsar.broker.admin.v2.Namespaces.createNamespace(Namespaces.java:138)
	at jdk.internal.reflect.GeneratedMethodAccessor171.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory.lambda$static$0(ResourceMethodInvocationHandlerFactory.java:52)
	at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:124)
	at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:167)
	at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$VoidOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:159)
	at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:79)
	at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:475)
	at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:397)
	at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:81)
	at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:255)
	at org.glassfish.jersey.internal.Errors$1.call(Errors.java:248)
	at org.glassfish.jersey.internal.Errors$1.call(Errors.java:244)
	at org.glassfish.jersey.internal.Errors.process(Errors.java:292)
	at org.glassfish.jersey.internal.Errors.process(Errors.java:274)
	at org.glassfish.jersey.internal.Errors.process(Errors.java:244)
	at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:265)
	at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:234)
	at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:680)
	at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:394)
	at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:346)
	at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:366)
	at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:319)
	at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:205)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:799)
	at org.eclipse.jetty.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1626)
	at org.apache.pulsar.broker.web.ResponseHandlerFilter.doFilter(ResponseHandlerFilter.java:67)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:548)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1434)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:501)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1349)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:234)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)
	at org.eclipse.jetty.server.handler.StatisticsHandler.handle(StatisticsHandler.java:179)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
	at org.eclipse.jetty.server.Server.handle(Server.java:516)
	at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:388)
	at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:633)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:380)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)
	at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:386)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: (was java.lang.NullPointerException) (through reference chain: org.apache.pulsar.common.policies.data.Policies["backlog_quota_map"]->java.util.LinkedHashMap["message_age"]->org.apache.pulsar.common.policies.data.impl.BacklogQuotaImpl["limit"])
	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:390)
	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:349)
	at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:316)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:778)
	at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeOptionalFields(MapSerializer.java:869)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithoutTypeInfo(MapSerializer.java:760)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:720)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:35)
	at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:770)
	at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:480)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:319)
	at com.fasterxml.jackson.databind.ObjectMapper._writeValueAndClose(ObjectMapper.java:4487)
	at com.fasterxml.jackson.databind.ObjectMapper.writeValueAsBytes(ObjectMapper.java:3765)
	at org.apache.pulsar.metadata.cache.impl.JSONMetadataSerdeSimpleType.serialize(JSONMetadataSerdeSimpleType.java:37)
	at org.apache.pulsar.metadata.cache.impl.MetadataCacheImpl.create(MetadataCacheImpl.java:211)
	at org.apache.pulsar.broker.resources.BaseResources.createAsync(BaseResources.java:141)
	at org.apache.pulsar.broker.resources.BaseResources.create(BaseResources.java:131)
	... 65 more
Caused by: java.lang.NullPointerException
	at org.apache.pulsar.common.policies.data.impl.BacklogQuotaImpl.getLimit(BacklogQuotaImpl.java:61)
	at jdk.internal.reflect.GeneratedMethodAccessor181.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:689)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:770)
	... 81 more

[zbentley]

@Shoothzj thanks for the fix! Works great1

[Shoothzj]

@zbentley Thanks for your report. Today I will prepare a PR fix this issue. I can’t read slack message now, I will check slack message six hours after