Split XML bodies are sometimes mixed in aggregation result of Split-Aggregation

[Hooghof]

Splits get sometime mixed in aggregated result in split-aggregate step. I suspect the split parallel setting, because other, not parallel, aggregations go well.

Test case

Instance: next
Tenant: Regression Tests
Flow: SplitXml_xml_aggr_rr_parallel

Step settings:

Use input to send to https://next.dovetail.world/test/inbound_http/regressiontests/SplitXml_xml_aggr_rr_parallel. In this flow it is not possible to use setbody with the input.

Input

<filmsoptv datum="18-10-2023">
    <film>
        <ft_link>19182</ft_link>
        <titel>Jack Reacher</titel>
        <jaar>2012</jaar>
    </film>
    <film>
        <ft_link>23843</ft_link>
        <titel>Spider-Man: Homecoming</titel>
        <jaar>2017</jaar>
    </film>
    <film>
        <ft_link>15557</ft_link>
        <titel>Clash of the Titans</titel>
        <jaar>2010</jaar>
    </film>
</filmsoptv>

Expected output on development

<Aggregated>
    <film>
        <ft_link>19182</ft_link>
        <titel>Jack Reacher</titel>
        <jaar>2012</jaar>
    </film>
    <film>
        <ft_link>23843</ft_link>
        <titel>Spider-Man: Homecoming</titel>
        <jaar>2017</jaar>
    </film>
    <film>
        <ft_link>15557</ft_link>
        <titel>Clash of the Titans</titel>
        <jaar>2010</jaar>
    </film>
</Aggregated>

Mixed result on next

<Aggregated>
    <film>
        <ft_link>23843</ft_link>
        <titel>Spider-Man: Homecoming</titel>
        <jaar/>
    </film>
    <film>
        <ft_link>23843</ft_link>
        <titel>Jack Reacher</titel>
        <jaar>2012</jaar>
    </film>
    <film>
        <ft_link>15557</ft_link>
        <titel>Spider-Man: Homecoming</titel>
        <jaar>2017</jaar>
    </film>
</Aggregated>

or

<Aggregated>
    <film>
        <ft_link>19182</ft_link>
        <titel>Jack Reacher</titel>
        <jaar/>
    </film>
    <film>
        <ft_link>15557</ft_link>
        <titel>Jack Reacher</titel>
        <jaar/>
    </film>
    <film>
        <ft_link>15557</ft_link>
        <titel>Clash of the Titans</titel>
        <jaar>2010</jaar>
    </film>
</Aggregated>

[brunovg]

This happens because standard xpath evaluation returns a live DOM NodeList (org.w3c.dom.Node). DOM node trees are not thread-safe.
When parallelProcessing is enabled, concurrent worker threads share references to the same underlying DOM document nodes in memory, causing race conditions and overwriting payloads.

I tried a few things but without success.