Aklakan opened a new issue, #2924:
URL: https://github.com/apache/jena/issues/2924
### Version
5.3.0-SNAPSHOT
### What happened?
The first query reveals a bug where an unexpected exception is raised in
`BindingBuilder.checkAdd`: `Attempt to reassign ?s from 1 to 1`. The issue is
in `QueryIterLateral` which just adds the lhs and rhs binding to the builder
although they may have variables in common.
```sparql
SELECT * {
BIND(1 AS ?s)
LATERAL {
BIND(?s AS ?x)
LATERAL {
BIND(?s AS ?y)
}
}
}
```
My proposed solution in the PR is to add a check whether bindings are
compatible on their common variables.
The second query fails a scope check in `SyntaxVarScope.checkLATERAL` when
tables (or binds) are involved and I am not sure if this behavior is intended
or not. This might be more related to the concepts of SEP-0007 rather than the
Jena implementation.
```sparql
SELECT * {
BIND(1 AS ?x)
LATERAL {
VALUES ?x { 1 2 }
}
}
```
I don't think that such a query should be invalid because this would
generally prevent materialization of graph pattern into a `VALUES` block.
I.e. IMHO it should be possible to substitute `... LATERAL { graph-pattern
}` with a corresponding `... LATERAL { VALUES { materialized-graph-pattern } }`.
### Relevant output and stacktrace
_No response_
### Are you interested in making a pull request?
Yes
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