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https://issues.apache.org/jira/browse/COLLECTIONS-714?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16937640#comment-16937640
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Chen commented on COLLECTIONS-714:
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Because 0=‘\u0000’ we can't fix this problem, we need to add comments to
explain this situation at PatriciaTrie.
Don't support '\u0000' in the key.
> PatriciaTrie ignores trailing null characters in keys
> -----------------------------------------------------
>
> Key: COLLECTIONS-714
> URL: https://issues.apache.org/jira/browse/COLLECTIONS-714
> Project: Commons Collections
> Issue Type: Bug
> Components: Collection, Map
> Affects Versions: 4.3
> Reporter: Rohan Padhye
> Priority: Critical
>
> In Java, strings are not null terminated. The string "x" (of length = 1 char)
> is different from the string "x\u0000" (of length = 2 chars). However,
> PatriciaTrie does not seem to distinguish between these strings.
> To reproduce:
> {code:java}
> public void testNullTerminatedKey1() {
> Map<String, Integer> map = new HashMap<>();
> map.put("x", 0); // key of length 1
> map.put("x\u0000", 1); // key of length 2
> map.put("x\u0000y", 2); // key of length 3
> Assert.assertEquals(3, map.size()); // ok, 3 distinct keys
> PatriciaTrie<Integer> trie = new PatriciaTrie<>(map);
> Assert.assertEquals(3, trie.size()); // fail; actual=2
> }{code}
> In the above example, the resulting trie has only two keys: "x\u0000" and
> "x\u0000y". The key "x" gets overwritten. Here is another way to repro the
> bug:
> {code:java}
> public void testNullTerminatedKey2() {
> PatriciaTrie<Integer> trie = new PatriciaTrie<>();
> trie.put("x", 0);
> Assert.assertTrue(trie.containsKey("x")); // ok
> trie.put("x\u0000", 1);
> Assert.assertTrue(trie.containsKey("x")); // fail
> }
> {code}
> In the above example, the key "x" suddenly disappears when an entry with key
> "x\u0000" is inserted.
> The PatriciaTrie docs do not mention anything about null-terminated strings.
> In general, I believe this also breaks the JDK Map contract since the keys
> "x".equals("x\u0000") is false.
> This bug was found automatically using JQF:
> [https://github.com/rohanpadhye/jqf].
>
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