Copilot commented on code in PR #8192:
URL: https://github.com/apache/hbase/pull/8192#discussion_r3291012771
##########
hbase-server/src/main/java/org/apache/hadoop/hbase/master/ServerManager.java:
##########
@@ -980,11 +980,14 @@ public synchronized boolean isServerDead(ServerName
serverName) {
/**
* Check if a server is unknown. A server can be online, or known to be
dead, or unknown to this
* manager (i.e, not online, not known to be dead either; it is simply not
tracked by the master
- * any more, for example, a very old previous instance).
+ * any more, for example, a very old previous instance). A null serverName
should not be
+ * considered unknown. We set regionLocation null before finding the assign
candidate (in-between
+ * region transition) or while marking it OFFLINE/FAILED_OPEN For more info
regarding null-check
+ * in this refer HBASE-30142
Review Comment:
The new Javadoc text for `isServerUnknown` is hard to read and contains
grammatical issues (e.g., “We set regionLocation null…”, “For more info
regarding null-check in this refer…”), and it’s missing punctuation. Please
rewrite this as clear, complete sentences (and explicitly reference
HBASE-30142) so the intent of the null-handling is unambiguous for future
readers.
##########
hbase-server/src/test/java/org/apache/hadoop/hbase/master/TestRecoverUnknownWithNullRegionLocation.java:
##########
@@ -0,0 +1,112 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.master;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.apache.hadoop.hbase.HBaseTestingUtil;
+import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.RegionInfo;
+import org.apache.hadoop.hbase.client.Table;
+import org.apache.hadoop.hbase.master.assignment.AssignmentManager;
+import org.apache.hadoop.hbase.master.assignment.RegionStateNode;
+import org.apache.hadoop.hbase.testclassification.MasterTests;
+import org.apache.hadoop.hbase.testclassification.MediumTests;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+
+import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos;
+
+/**
+ * Test for HBASE-30142. Verifies that {@code scheduleSCPsForUnknownServers}
(i.e. the
+ * recoverUnknown HBCK command) does not throw a NullPointerException when a
region's
+ * {@code regionLocation} is null while its state is something other than
OFFLINE.
+ * <p/>
+ * Before HBASE-30142, {@link
ServerManager#isServerUnknown(org.apache.hadoop.hbase.ServerName)}
+ * returned {@code true} for a {@code null} server name, so a region whose
location had been
+ * temporarily nulled (e.g. between region transitions or while marking it
FAILED_OPEN /
+ * ABNORMALLY_CLOSED) was treated as living on an "unknown" server. The
downstream call to
+ * {@code shouldSubmitSCP(null)} then dereferenced the null and crashed.
+ */
+@Tag(MasterTests.TAG)
+@Tag(MediumTests.TAG)
+public class TestRecoverUnknownWithNullRegionLocation {
+
+ private static HBaseTestingUtil UTIL;
+ private static final TableName TABLE_NAME =
+ TableName.valueOf("TestRecoverUnknownWithNullRegionLocation");
+ private static final byte[] FAMILY = Bytes.toBytes("cf");
+
+ @BeforeAll
+ public static void setUpBeforeClass() throws Exception {
+ UTIL = new HBaseTestingUtil();
+ UTIL.startMiniCluster(2);
+ }
+
+ @AfterAll
+ public static void tearDownAfterClass() throws Exception {
+ if (UTIL != null) {
+ UTIL.shutdownMiniCluster();
+ }
+ }
+
+ /**
+ * Drive the region into ABNORMALLY_CLOSED through the
+ * {@link AssignmentManager#regionClosedAbnormally(RegionStateNode)} path
(the same path SCP
+ * uses). That method also nulls {@code regionLocation} while leaving state
non-OFFLINE. Then call
+ * {@code scheduleSCPsForUnknownServers} and assert no NPE.
+ */
+ @Test
+ public void testRecoverUnknownWithAbnormallyClosedRegion() throws Exception {
+ try (Table ignored = UTIL.createTable(TABLE_NAME, FAMILY)) {
+ UTIL.waitTableAvailable(TABLE_NAME);
+
+ HMaster master = UTIL.getMiniHBaseCluster().getMaster();
+ AssignmentManager am = master.getAssignmentManager();
+ List<RegionInfo> regions = am.getTableRegions(TABLE_NAME, true);
+ assertFalse(regions.isEmpty(), "expected at least one region");
+ RegionStateNode node =
am.getRegionStates().getRegionStateNode(regions.get(0));
+ assertNotNull(node, "expected a region state node for the test region");
+
+ node.lock();
+ try {
+ am.regionClosedAbnormally(node).get();
+ } finally {
+ node.unlock();
+ }
+
+ assertTrue(node.isInState(RegionState.State.ABNORMALLY_CLOSED),
+ "regionClosedAbnormally must move state to ABNORMALLY_CLOSED");
+ assertNull(node.getRegionLocation(), "regionClosedAbnormally must null
out the location");
+
+ MasterProtos.ScheduleSCPsForUnknownServersResponse response =
+ master.getMasterRpcServices().scheduleSCPsForUnknownServers(null,
+
MasterProtos.ScheduleSCPsForUnknownServersRequest.newBuilder().build());
Review Comment:
The assertions and the `scheduleSCPsForUnknownServers` call are done after
releasing the `RegionStateNode` lock. Since `RegionStateNode` is generally
expected to be accessed under its lock, this can become racy/flaky if another
procedure/thread modifies the node between unlock and these checks. Consider
keeping the lock held (or re-locking) while asserting state/location and
issuing the recoverUnknown RPC.
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