You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@lucene.apache.org by "Robert Muir (JIRA)" <ji...@apache.org> on 2010/10/29 14:58:47 UTC
[jira] Updated: (LUCENE-2216) OpenBitSet#hashCode() may return
false for identical sets.
[ https://issues.apache.org/jira/browse/LUCENE-2216?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Robert Muir updated LUCENE-2216:
--------------------------------
Fix Version/s: (was: 4.0)
3.0.3
2.9.4
> OpenBitSet#hashCode() may return false for identical sets.
> ----------------------------------------------------------
>
> Key: LUCENE-2216
> URL: https://issues.apache.org/jira/browse/LUCENE-2216
> Project: Lucene - Java
> Issue Type: Bug
> Components: Other
> Affects Versions: 2.9, 2.9.1, 3.0
> Reporter: Dawid Weiss
> Priority: Minor
> Fix For: 2.9.4, 3.0.3
>
> Attachments: LUCENE-2216.patch, openbitset.patch
>
>
> OpenBitSet uses an internal buffer of long variables to store set bits and an additional 'wlen' index that points
> to the highest used component inside {@link #bits} buffer.
> Unlike in JDK, the wlen field is not continuously maintained (on clearing bits, for example). This leads to a situation when wlen may point
> far beyond the last set bit.
> The hashCode implementation iterates over all long components of the bits buffer, rotating the hash even for empty components. This is against the contract of hashCode-equals. The following test case illustrates this:
> {code}
> // initialize two bitsets with different capacity (bits length).
> BitSet bs1 = new BitSet(200);
> BitSet bs2 = new BitSet(64);
> // set the same bit.
> bs1.set(3);
> bs2.set(3);
>
> // equals returns true (passes).
> assertEquals(bs1, bs2);
> // hashCode returns false (against contract).
> assertEquals(bs1.hashCode(), bs2.hashCode());
> {code}
> Fix and test case attached.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@lucene.apache.org
For additional commands, e-mail: dev-help@lucene.apache.org