IndexOutOfBoundsException when using "in" function in GeoServer

I have trouble with the in filter function in SLD submitted to GeoServer. The root cause seems to be within the geotools. Currently we’re using GeoServer Version 2.15.2 and GeoTools Version 21.2. The fact is that with less complex filters the in function seems to work but in this case it does not. We found also an workaround by using or in combination with PropertyIsEqualTo but then the payload is much bigger. I’ve tried also to split the in function into smaller parts so it matches in9 or in10 but then i got similar IndexOutOfBoundsException.

      <ogc:Filter>
        <ogc:And>
          <ogc:Or>
            <PropertyIsEqualTo>
              <ogc:Function name="geometryType">
                <ogc:PropertyName>geom</ogc:PropertyName>
              </ogc:Function>
              <ogc:Literal>Point</ogc:Literal>
            </PropertyIsEqualTo>
            <PropertyIsEqualTo>
              <ogc:Function name="geometryType">
                <ogc:PropertyName>geom</ogc:PropertyName>
              </ogc:Function>
              <ogc:Literal>MultiPoint</ogc:Literal>
            </PropertyIsEqualTo>
          </ogc:Or>
          <ogc:And>
            <ogc:PropertyIsEqualTo>
              <ogc:Function name="in">
                <ogc:Function name="property">
                  <ogc:Literal>feature_type_id</ogc:Literal>
                </ogc:Function>
                <ogc:Literal>7516</ogc:Literal>
                <ogc:Literal>7517</ogc:Literal>
                <ogc:Literal>7518</ogc:Literal>
                <ogc:Literal>7519</ogc:Literal>
                <ogc:Literal>7520</ogc:Literal>
                <ogc:Literal>7521</ogc:Literal>
                <ogc:Literal>7522</ogc:Literal>
                <ogc:Literal>7523</ogc:Literal>
                <ogc:Literal>7524</ogc:Literal>
                <ogc:Literal>7525</ogc:Literal>
                <ogc:Literal>7526</ogc:Literal>
                <ogc:Literal>7527</ogc:Literal>
                <ogc:Literal>7528</ogc:Literal>
                <ogc:Literal>7529</ogc:Literal>
                <ogc:Literal>7530</ogc:Literal>
                <ogc:Literal>7531</ogc:Literal>
                <ogc:Literal>7532</ogc:Literal>
                <ogc:Literal>7533</ogc:Literal>
                <ogc:Literal>7534</ogc:Literal>
                <ogc:Literal>7535</ogc:Literal>
                <ogc:Literal>7536</ogc:Literal>
              </ogc:Function>
              <ogc:Literal>true</ogc:Literal>
            </ogc:PropertyIsEqualTo>
          </ogc:And>
        </ogc:And>
      </ogc:Filter>

The generated SLD may be found here https://www.swisstransfer.com/d/99631cf1-9172-4f46-979a-00c0e77b47d2

Here is a part of the stacktrace:

Caused by: java.lang.IndexOutOfBoundsException: Index 7 out of bounds for length 4
    at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:64)
    at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:70)
    at java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:248)
    at java.base/java.util.Objects.checkIndex(Objects.java:372)
    at java.base/java.util.ArrayList.get(ArrayList.java:458)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visit(PostPreProcessFilterSplittingVisitor.java:873)
    at org.geotools.filter.FunctionExpressionImpl.accept(FunctionExpressionImpl.java:143)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visitBinaryComparisonOperator(PostPreProcessFilterSplittingVisitor.java:423)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visit(PostPreProcessFilterSplittingVisitor.java:377)
    at org.geotools.filter.IsEqualsToImpl.accept(IsEqualsToImpl.java:154)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visitLogicOperator(PostPreProcessFilterSplittingVisitor.java:670)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visit(PostPreProcessFilterSplittingVisitor.java:599)
    at org.geotools.filter.AndImpl.accept(AndImpl.java:45)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visitLogicOperator(PostPreProcessFilterSplittingVisitor.java:627)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visit(PostPreProcessFilterSplittingVisitor.java:604)
    at org.geotools.filter.NotImpl.accept(NotImpl.java:51)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visitLogicOperator(PostPreProcessFilterSplittingVisitor.java:670)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visit(PostPreProcessFilterSplittingVisitor.java:599)
    at org.geotools.filter.AndImpl.accept(AndImpl.java:45)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visitLogicOperator(PostPreProcessFilterSplittingVisitor.java:627)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visit(PostPreProcessFilterSplittingVisitor.java:604)
    at org.geotools.filter.NotImpl.accept(NotImpl.java:51)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visitLogicOperator(PostPreProcessFilterSplittingVisitor.java:649)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visit(PostPreProcessFilterSplittingVisitor.java:609)
    at org.geotools.filter.OrImpl.accept(OrImpl.java:41)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visitLogicOperator(PostPreProcessFilterSplittingVisitor.java:670)
    at org.geotools.filter.visitor.PostPreProcessFilterSplittingVisitor.visit(PostPreProcessFilterSplittingVisitor.java:599)
    at org.geotools.filter.AndImpl.accept(AndImpl.java:45)

I’ve also tried to create a unit test in PostPreProcessFilterSplittingVisitorTest in geotools which would simulate a part of the xml, but it does not throw any exception

final Not not =
  ff.not(
    ff.and(
      ff.or(
        ff.equal(
          ff.function("geometryType", ff.property("geom")),
            ff.literal("Point"),
            true,
            MultiValuedFilter.MatchAction.ANY
        ),
        ff.equal(
          ff.function("geometryType", ff.property("geom")),
          ff.literal("MultiPoint"),
          true,
          MultiValuedFilter.MatchAction.ANY
        )
      ),
      ff.equal(
        ff.function(
          "in", 
          ff.function("property", ff.literal("feature_type_id")),
          ff.literal(7516),
          ff.literal(7517),
          ff.literal(7518),
          ff.literal(7519),
          ff.literal(7520),
          ff.literal(7521),
          ff.literal(7522),
          ff.literal(7523),
          ff.literal(7524),
          ff.literal(7525),
          ff.literal(7526),
          ff.literal(7527),
          ff.literal(7528),
          ff.literal(7529),
          ff.literal(7530),
          ff.literal(7531),
          ff.literal(7532),
          ff.literal(7533),
          ff.literal(7534),
          ff.literal(7535),
          ff.literal(7536)
        ),
        ff.literal(true),
        true,
        MultiValuedFilter.MatchAction.ANY
      )
    )
  );
  final And andFilter = ff.and(Collections.singletonList(not));
  final PostPreProcessFilterSplittingVisitor postprocessFilter =
                newVisitor(new FilterCapabilities());
        
  andFilter.accept(postprocessFilter, null);