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FIX: Skip if nodeSet return null when already removed #1122

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Merged
jhpark816 merged 1 commit into from
Oct 14, 2026
Merged

FIX: Skip if nodeSet return null when already removed #1122

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13 changes: 9 additions & 4 deletions src/main/java/net/spy/memcached/ArcusKetamaNodeLocator.java
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Original file line number Diff line number Diff line change
Expand Up @@ -315,7 +315,10 @@ private void removeHash(MemcachedNode node) {
for (int h = 0; h < 4; h++) {
Long k = getKetamaHashPoint(digest, h);
SortedSet<MemcachedNode> nodeSet = ketamaNodes.get(k);
assert nodeSet != null;
if (nodeSet == null) {
// The hash point is duplicated in the node itself and already removed.
continue;
}
nodeSet.remove(node);
if (nodeSet.isEmpty()) {
ketamaNodes.remove(k);
Expand Down Expand Up @@ -384,12 +387,14 @@ private void removeHashOfAlter(MemcachedNode node) {
}
} else {
nodeSet = ketamaNodes.get(k);
assert nodeSet != null;
boolean removed = nodeSet.remove(node);
if (nodeSet == null) {
// The hash point is duplicated in the node itself and already removed.
continue;
}
nodeSet.remove(node);
if (nodeSet.isEmpty()) {
ketamaNodes.remove(k);
}
assert removed;
}
}
}
Expand Down
71 changes: 71 additions & 0 deletions src/test/java/net/spy/memcached/ArcusKetamaHashingTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,8 @@

import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.List;
import java.util.Map;
Expand All @@ -13,6 +15,7 @@
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertNotSame;
import static org.junit.jupiter.api.Assertions.assertTrue;

class ArcusKetamaHashingTest {
Expand Down Expand Up @@ -60,6 +63,74 @@ void testHashCollision() {
runThisManyNodes(stringNode1, stringNode2);
}

@Test
void testRemoveNodeWithDuplicateHashPointInSelf() {
/* "127.0.7.1:12932" has a duplicate hash point in its own hash points. */
List<MemcachedNode> nodes = createNodes(
AddrUtil.getAddresses(Arrays.asList("127.0.0.1:11211", "127.0.0.2:11211")));
MemcachedNode dupNode = new MockMemcachedNode(
new InetSocketAddress("127.0.7.1", 12932));

ArcusKetamaNodeLocator locator =
new ArcusKetamaNodeLocator(nodes, new ArcusKetamaNodeLocatorConfiguration());
locator.update(Collections.singletonList(dupNode),
Collections.<MemcachedNode>emptyList());
assertTrue(locator.getAll().contains(dupNode));

locator.update(Collections.<MemcachedNode>emptyList(),
Collections.singletonList(dupNode));
assertFalse(locator.getAll().contains(dupNode));
assertNoHashPointOf(locator, dupNode);
}

@Test
void testRemoveJoiningAlterNodeWithDuplicateHashPointInSelf() {
/* "127.0.7.1:12932" has a duplicate hash point in its own hash points. */
List<MemcachedNode> nodes = createNodes(
AddrUtil.getAddresses(Arrays.asList("127.0.0.1:11211", "127.0.0.2:11211")));
MemcachedNode dupNode = new MockMemcachedNode(
new InetSocketAddress("127.0.7.1", 12932));

ArcusKetamaNodeLocator locator =
new ArcusKetamaNodeLocator(nodes, new ArcusKetamaNodeLocatorConfiguration());
locator.prepareMigration(Collections.singletonList(dupNode), MigrationType.JOIN);
assertTrue(locator.getAlterAll().contains(dupNode));

locator.updateAlter(Collections.<MemcachedNode>emptyList(),
Collections.singletonList(dupNode));
assertTrue(locator.getAlterAll().isEmpty());
assertNoHashPointOf(locator, dupNode);
}

@Test
void testRemoveLeavingAlterNodeWithDuplicateHashPointInSelf() {
/* "127.0.7.1:12932" has a duplicate hash point in its own hash points. */
List<MemcachedNode> nodes = createNodes(
AddrUtil.getAddresses(Arrays.asList("127.0.0.1:11211", "127.0.0.2:11211")));
MemcachedNode dupNode = new MockMemcachedNode(
new InetSocketAddress("127.0.7.1", 12932));

ArcusKetamaNodeLocator locator =
new ArcusKetamaNodeLocator(nodes, new ArcusKetamaNodeLocatorConfiguration());
locator.update(Collections.singletonList(dupNode),
Collections.<MemcachedNode>emptyList());
locator.prepareMigration(Collections.singletonList(dupNode), MigrationType.LEAVE);
assertTrue(locator.getAlterAll().contains(dupNode));

locator.updateAlter(Collections.<MemcachedNode>emptyList(),
Collections.singletonList(dupNode));
assertTrue(locator.getAlterAll().isEmpty());
assertNoHashPointOf(locator, dupNode);
}

private void assertNoHashPointOf(ArcusKetamaNodeLocator locator, MemcachedNode target) {
for (SortedSet<MemcachedNode> nodeSet : locator.getKetamaNodes().values()) {
for (MemcachedNode node : nodeSet) {
assertNotSame(target, node);
}
}
}

/**
* Simulate dropping from stringNode1 to stringNode2.
* Ensure hashing is consistent between the the two scenarios.
Expand Down
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