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Posted to issues@commons.apache.org by "Ng Tsz Sum (Jira)" <ji...@apache.org> on 2022/04/22 15:48:00 UTC
[jira] [Commented] (COLLECTIONS-802) ReferenceMap iterator remove violates contract
[ https://issues.apache.org/jira/browse/COLLECTIONS-802?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17526507#comment-17526507 ]
Ng Tsz Sum commented on COLLECTIONS-802:
----------------------------------------
runnable with java 8, same result as stated
{code:java}
@Test
public void iterator_remove_failed_after_hasNext() {
ReferenceMap<Integer, Integer> map = new ReferenceMap<>();
map.put(1, 2);
Iterator<Map.Entry<Integer, Integer>> iter = map.entrySet().iterator();
assertTrue(iter.hasNext());
assertTrue(iter.hasNext());
assertEquals(iter.next().getValue(), new Integer(2));
// comment below hasNext() call will pass
assertFalse(iter.hasNext());
iter.remove();
assertTrue("Expect empty but have entry: " + map.toString(), map.isEmpty());
}
{code}
> 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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