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https://issues.apache.org/jira/browse/COLLECTIONS-802?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17526562#comment-17526562
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Ben Manes edited comment on COLLECTIONS-802 at 4/22/22 5:01 PM:
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Caffeine's 
[implementation|https://github.com/ben-manes/caffeine/blob/f52062955adb749e7828d1f1cff12a9eea26bee4/caffeine/src/main/java/com/github/benmanes/caffeine/cache/BoundedLocalCache.java#L3485]
 also modified state during the hasNext(), but it caches on next() the removal 
key to decouple it from the cursor's current entry.

 


was (Author: ben.manes):
Caffeine's 
[implementation|https://github.com/ben-manes/caffeine/blob/f52062955adb749e7828d1f1cff12a9eea26bee4/caffeine/src/main/java/com/github/benmanes/caffeine/cache/BoundedLocalCache.java#L3452-L3455]
 also modified state during the hasNext(), but it caches on next() the removal 
key to decouple it from the cursor's current entry.

 

> ReferenceMap iterator remove violates contract
> ----------------------------------------------
>
>                 Key: COLLECTIONS-802
>                 URL: https://issues.apache.org/jira/browse/COLLECTIONS-802
>             Project: Commons Collections
>          Issue Type: Bug
>          Components: Map
>    Affects Versions: 4.4
>            Reporter: Ben Manes
>            Priority: Minor
>         Attachments: ApacheMapTest.java
>
>
> Out of curiosity I ran Guava's testlib Map tests against the Apache types. 
> This uncovered a contract bug where {{Iterator.remove()}} is invalidated by 
> {{{}hasNext(){}}}, causing its call to no-op due to {{currentKey}} becoming 
> {{{}null{}}}. The isolates case is,
> {code:java}
> @Test
> public void iterator_remove() {
>   var map = new ReferenceMap<>();
>   map.put(1, 2);
>   var iter = map.entrySet().iterator();
>   assertTrue(iter.hasNext());
>   assertTrue(iter.hasNext());
>   assertEquals(iter.next(), 1);
>   assertFalse(iter.hasNext());
>   iter.remove();
>   assertEquals(map, Map.of());
> }{code}
> Guava's [testlib|https://github.com/google/guava/tree/master/guava-testlib] 
> has good coverage for the Collections Framework and might be worth 
> integrating. The simple test case that I wrote is attached.



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