[fix][broker]fix npe when invoke replaceBookie.

[Nicklee007]

Motivation

Fix the npe when the ISOLATION_BOOKIE_GROUPS is "" or missed which will produce in follow two case and can be reproduce by the unit test in this PR also.

The npe point

pulsar/pulsar-broker-common/src/main/java/org/apache/pulsar/bookie/rackawareness/IsolatedBookieEnsemblePlacementPolicy.java

Line 220 in eeb22ba

if (isolationGroups != null && isolationGroups.getLeft().contains(PULSAR_SYSTEM_TOPIC_ISOLATION_GROUP)) {

pulsar/pulsar-broker-common/src/main/java/org/apache/pulsar/bookie/rackawareness/IsolatedBookieEnsemblePlacementPolicy.java

Line 247 in eeb22ba

if (!primaryIsolationGroup.contains(group)) {

java.lang.NullPointerException: Cannot invoke "java.util.Set.contains(Object)" because the return value of "org.apache.commons.lang3.tuple.Pair.getLeft()" is null

	at org.apache.pulsar.bookie.rackawareness.IsolatedBookieEnsemblePlacementPolicy.getBlacklistedBookiesWithIsolationGroups(IsolatedBookieEnsemblePlacementPolicy.java:220)
	at org.apache.pulsar.bookie.rackawareness.IsolatedBookieEnsemblePlacementPolicy.replaceBookie(IsolatedBookieEnsemblePlacementPolicy.java:170)
	at org.apache.pulsar.bookie.rackawareness.IsolatedBookieEnsemblePlacementPolicyTest.testNoIsolationGroup(IsolatedBookieEnsemblePlacementPolicyTest.java:319)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:132)
	at org.testng.internal.TestInvoker.invokeMethod(TestInvoker.java:599)
	at org.testng.internal.TestInvoker.invokeTestMethod(TestInvoker.java:174)
	at org.testng.internal.MethodRunner.runInSequence(MethodRunner.java:46)
	at org.testng.internal.TestInvoker$MethodInvocationAgent.invoke(TestInvoker.java:822)
	at org.testng.internal.TestInvoker.invokeTestMethods(TestInvoker.java:147)
	at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:146)
	at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:128)

Case 1:
When we set strictBookieAffinityEnabled = true and if some namespaces not set bookieAffinityGroup , and then those namespaces will be set ISOLATION_BOOKIE_GROUPS as "" by default, which will cause npe when invoke replaceBookie.

pulsar/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java

Line 1513 in eeb22ba

if (serviceConfig.isStrictBookieAffinityEnabled()) {

pulsar/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java

Lines 1529 to 1534 in eeb22ba

	} else {
	Map<String, Object> properties = Maps.newHashMap();
	properties.put(IsolatedBookieEnsemblePlacementPolicy.ISOLATION_BOOKIE_GROUPS, "");
	properties.put(IsolatedBookieEnsemblePlacementPolicy.SECONDARY_ISOLATION_BOOKIE_GROUPS, "");
	managedLedgerConfig.setBookKeeperEnsemblePlacementPolicyProperties(properties);
	}

Case 2:
When the bookieAffinityGroup is not null and the ISOLATION_BOOKIE_GROUPS is null or "" also cause npe

Modifications

Describe the modifications you've done.
set a default value when primaryIsolationGroupString is empty.

• doc-not-needed

[Nicklee007]

/pulsarbot run-failure-checks