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https://issues.apache.org/jira/browse/LUCENE-5897?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14104519#comment-14104519
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Steve Rowe commented on LUCENE-5897:
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I'll try to figure out a way to limit the search, as you say, to to
maxTokenLength(). I worry about two things though, both of which are currently
handled (though badly in these adversary cases):
# in a rule with alternates, one of which is satisfied below the limit, the
satisfied alternate should produce a match when a partially matching alternate
exceeds the limit and is aborted.
# When rule A matches partially, exceeds the limit, and is aborted, and rule B
matches a prefix that is under the limit, rule B should produce a match.
> performance bug ("adversary") in StandardTokenizer
> --------------------------------------------------
>
> Key: LUCENE-5897
> URL: https://issues.apache.org/jira/browse/LUCENE-5897
> Project: Lucene - Core
> Issue Type: Bug
> Reporter: Robert Muir
>
> There seem to be some conditions (I don't know how rare or what conditions)
> that cause StandardTokenizer to essentially hang on input: I havent looked
> hard yet, but as its essentially a DFA I think something wierd might be going
> on.
> An easy way to reproduce is with 1MB of underscores, it will just hang
> forever.
> {code}
> public void testWorthyAdversary() throws Exception {
> char buffer[] = new char[1024 * 1024];
> Arrays.fill(buffer, '_');
> int tokenCount = 0;
> Tokenizer ts = new StandardTokenizer();
> ts.setReader(new StringReader(new String(buffer)));
> ts.reset();
> while (ts.incrementToken()) {
> tokenCount++;
> }
> ts.end();
> ts.close();
> assertEquals(0, tokenCount);
> }
> {code}
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