Rohan Padhye created COLLECTIONS-714: ----------------------------------------
Summary: 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 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} @Test 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} @Test 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 PatriciaKey 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]]. -- This message was sent by Atlassian JIRA (v7.6.3#76005)