[rules-dev] Analysis: variable constraint with index causes SIOOBEx

[Wolfgang Laun]

5.1 and trunk permits you to write e.g.

   Foo( $array: array )
   Bar( this == $array[0] )

but this crashes druing compilation with
 java.lang.StringIndexOutOfBoundsException: String index out of range: -1
    at java.lang.String.substring(String.java:1949)
    at
org.drools.rule.builder.PatternBuilder.buildRestriction(PatternBuilder.java:928)

It's OK by this syntax:
   accessor_element ; ID square_chunk* ;

Processing in DescriptorFactory handles []:

createAccessorPath(List<BaseDescr> aeList) {
   ...
if (name.indexOf('.') > -1 || name.indexOf('[') > -1) {
            evaluator = new QualifiedIdentifierRestrictionDescr();

Then in PatternBuilder, we end up in this variant of the overloaded method
buildRestriction:

  private Restriction buildRestriction(final RuleBuildContext context,
                                         final InternalReadAccessor
extractor,
                                         final FieldConstraintDescr
fieldConstraintDescr,
                                         final
QualifiedIdentifierRestrictionDescr qiRestrictionDescr)

and this is where it happens, lastDot being == -1.

{        final int lastDot = qiRestrictionDescr.getText().lastIndexOf( '.'
);
        final String className = qiRestrictionDescr.getText().substring( 0,

lastDot );

If the syntax isn't too permissive, then this method would have to handle
x[y] in
addition to x.y, etc.

-W
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