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[COLLECTIONS-802] Fix remove failed by removing set null to currentKe… #300

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Merged
kinow merged 1 commit into from
Apr 28, 2022
Merged

[COLLECTIONS-802] Fix remove failed by removing set null to currentKe… #300

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24 changes: 11 additions & 13 deletions src/main/java/org/apache/commons/collections4/map/AbstractReferenceMap.java
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Original file line number Diff line number Diff line change
Expand Up @@ -772,8 +772,8 @@ static class ReferenceBaseIterator<K, V> {

// These fields keep track of where we are in the table.
int index;
ReferenceEntry<K, V> entry;
ReferenceEntry<K, V> previous;
ReferenceEntry<K, V> next;
ReferenceEntry<K, V> current;

// These Object fields provide hard references to the
// current and next entry; this assures that if hasNext()
Expand All @@ -794,23 +794,21 @@ static class ReferenceBaseIterator<K, V> {
public boolean hasNext() {
checkMod();
while (nextNull()) {
ReferenceEntry<K, V> e = entry;
ReferenceEntry<K, V> e = next;
int i = index;
while (e == null && i > 0) {
i--;
e = (ReferenceEntry<K, V>) parent.data[i];
}
entry = e;
next = e;
index = i;
if (e == null) {
currentKey = null;
currentValue = null;
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@kinow kinow Apr 28, 2022

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Fix is here ☝️ , the rest is renaming variables.

return false;
}
nextKey = e.getKey();
nextValue = e.getValue();
if (nextNull()) {
entry = entry.next();
next = next.next();
}
}
return true;
Expand All @@ -831,27 +829,27 @@ protected ReferenceEntry<K, V> nextEntry() {
if (nextNull() && !hasNext()) {
throw new NoSuchElementException();
}
previous = entry;
entry = entry.next();
current = next;
next = next.next();
currentKey = nextKey;
currentValue = nextValue;
nextKey = null;
nextValue = null;
return previous;
return current;
}

protected ReferenceEntry<K, V> currentEntry() {
checkMod();
return previous;
return current;
}

public void remove() {
checkMod();
if (previous == null) {
if (current == null) {
throw new IllegalStateException();
}
parent.remove(currentKey);
previous = null;
current = null;
currentKey = null;
currentValue = null;
expectedModCount = parent.modCount;
Expand Down
19 changes: 19 additions & 0 deletions src/test/java/org/apache/commons/collections4/map/ReferenceMapTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
import java.io.Serializable;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.function.Consumer;
Expand Down Expand Up @@ -315,6 +316,24 @@ public void testDataSizeAfterSerialization() throws IOException, ClassNotFoundEx

}

/**
* Test whether remove is not removing last entry after calling hasNext.
* <p>
* See <a href="https://issues.apache.org/jira/browse/COLLECTIONS-802">COLLECTIONS-802: ReferenceMap iterator remove violates contract</a>
*/
@Test
public void testIteratorLastEntryCanBeRemovedAfterHasNext() {
ReferenceMap<Integer, Integer> map = new ReferenceMap<>();
map.put(1, 2);
Iterator<Map.Entry<Integer, Integer>> iter = map.entrySet().iterator();
assertTrue(iter.hasNext());
iter.next();
// below line should not affect remove
assertFalse(iter.hasNext());
iter.remove();
assertTrue("Expect empty but have entry: " + map, map.isEmpty());
}
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@kinow kinow Apr 24, 2022

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Fix looks OK, and the test is failing on master, passing on this branch. We could also modify the test to be more similar to the one reported in the issue.

diff --git a/src/test/java/org/apache/commons/collections4/map/ReferenceMapTest.java b/src/test/java/org/apache/commons/collections4/map/ReferenceMapTest.java
index 509ac514..c6625909 100644
--- a/src/test/java/org/apache/commons/collections4/map/ReferenceMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/ReferenceMapTest.java
@@ -327,7 +327,8 @@ public class ReferenceMapTest<K, V> extends AbstractIterableMapTest<K, V> {
         map.put(1, 2);
         Iterator<Map.Entry<Integer, Integer>> iter = map.entrySet().iterator();
         assertTrue(iter.hasNext());
-        iter.next();
+        assertTrue(iter.hasNext());
+        assertEquals(Integer.valueOf(1), iter.next().getKey());
         // below line should not affect remove
         assertFalse(iter.hasNext());
         iter.remove();

But not really important, the last assertTrue is where the test fails on master.


@SuppressWarnings("unused")
private static void gc() {
try {
Expand Down