[jboss-jira] [JBoss JIRA] (JBRULES-3483) Off-by-one error in FullFastIterator.next() leads to botched queries

[RH Bugzilla Integration (JIRA)]

     [ https://issues.jboss.org/browse/JBRULES-3483?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

RH Bugzilla Integration updated JBRULES-3483:
---------------------------------------------

       Git Pull Request: https://github.com/droolsjbpm/drools/pull/117  (was: https://github.com/droolsjbpm/drools/pull/117)
    Bugzilla References: https://bugzilla.redhat.com/show_bug.cgi?id=816807

    
> Off-by-one error in FullFastIterator.next() leads to botched queries
> --------------------------------------------------------------------
>
>                 Key: JBRULES-3483
>                 URL: https://issues.jboss.org/browse/JBRULES-3483
>             Project: Drools
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: drools-core
>    Affects Versions: 5.4.0.CR1
>            Reporter: Adar Dembo
>            Assignee: Mark Proctor
>
> I'll reproduce the entirety of the method() below for clarity:
> {code}
>         public Entry next(Entry object) {
>             RightTuple rightTuple = ( RightTuple ) object;
>             RightTupleList list = null;
>             if ( rightTuple != null ) {
>                 list = rightTuple.getMemory(); // assumes you do not pass in a null RightTuple
>             }
>             int length = table.length;
>             while ( this.row < length ) {
>                 // check if there is a current bucket
>                 while ( list == null ) {
>                     // iterate while there is no current bucket, trying each array position
>                     list = (RightTupleList) this.table[this.row];
>                     this.row++;
>                     
>                     if ( list != null ) {
>                         // we have a bucket so assign the frist LeftTuple and return
>                         rightTuple = (RightTuple) list.getFirst( );
>                         return rightTuple;
>                     } else if ( this.row >= length ) {
>                         // we've scanned the whole table and nothing is left, so return null
>                         return null;
>                     }
>                     
>                 }
>                 rightTuple = (RightTuple) rightTuple.getNext();
>                 if ( rightTuple != null ) {
>                     // we have a next tuple so return
>                     return rightTuple;
>                 } else {
>                     list = (RightTupleList) list.getNext();
>                     // try the next bucket if we have a shared array position
>                     if ( list != null ) {
>                         // if we have another bucket, assign the first RightTuple and return
>                         rightTuple = (RightTuple) list.getFirst( );
>                         return rightTuple;
>                     }
>                 }
>             }
>             return null;
>         }
> {code}
> The problem is when we have a RightTupleList in the last row of the table, and that list has more than one RightTuple. The call to next() that brings us to this list will increment this.row so that it's now equal to table.length. A subsequent next() should retrieve the next RightTuple, but because all of that code is conditioned on (table.row < length), the iteration ends prematurely. This affects one of my queries, which for an object with a particular hash code was only returning the first match instead of all of the matches.
> I took a quick look at LeftTupleIndexHashTable.FullFastIterator, and since the code is identical, it's probably also broken.

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