```
show functions | keep description, *on | mv_expand description
```

```
{
    "error": {
        "root_cause": [
            {
                "type": "unresolved_exception",
                "reason": "Invalid call to dataType on an unresolved object ?description"
            }
        ],
        "type": "unresolved_exception",
        "reason": "Invalid call to dataType on an unresolved object ?description"
    },
    "status": 500
}
```

```
org.elasticsearch.xpack.ql.capabilities.UnresolvedException: Invalid call to dataType on an unresolved object ?description
        at org.elasticsearch.xpack.ql.expression.UnresolvedAttribute.dataType(UnresolvedAttribute.java:90)
        at org.elasticsearch.xpack.esql.analysis.Analyzer$ResolveRefs.resolveMvExpand(Analyzer.java:350)
        at org.elasticsearch.xpack.esql.analysis.Analyzer$ResolveRefs.doRule(Analyzer.java:334)
        at org.elasticsearch.xpack.ql.analyzer.AnalyzerRules$BaseAnalyzerRule.rule(AnalyzerRules.java:120)
        at org.elasticsearch.xpack.ql.analyzer.AnalyzerRules$AnalyzerRule.lambda$apply$0(AnalyzerRules.java:85)
```

It should throw a VerificationException and propagate the unresolved attribute message instead
x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/analysis/AnalyzerTests.java
assertEquals(1, eval.fields().size());
        assertEquals(new Alias(EMPTY, "e", new ReferenceAttribute(EMPTY, "emp_no", DataTypes.INTEGER)), eval.fields().get(0));
        assertEquals(2, eval.output().size());
        Attribute empNo = eval.output().get(0);
        assertEquals("emp_no", empNo.name());
        assertThat(empNo, instanceOf(ReferenceAttribute.class));
        Attribute e = eval.output().get(1);
        assertEquals("e", e.name());
        assertThat(e, instanceOf(ReferenceAttribute.class));
        Row row = (Row) eval.child();
        ReferenceAttribute rowEmpNo = (ReferenceAttribute) row.output().get(0);
        assertEquals(rowEmpNo.id(), empNo.id());
    }
    public void testUnresolvableAttribute() {
        Analyzer analyzer = analyzer(loadMapping("mapping-one-field.json", "idx"));
        VerificationException ve = expectThrows(
            VerificationException.class,
            () -> analyzer.analyze(
                new Eval(EMPTY, UNRESOLVED_RELATION, List.of(new Alias(EMPTY, "e", new UnresolvedAttribute(EMPTY, "emp_nos"))))
            )
        );
        assertThat(ve.getMessage(), containsString("Unknown column [emp_nos], did you mean [emp_no]?"));
    }
    public void testProjectBasic() {
        assertProjection("""
            from test
            | keep first_name
            """, "first_name");
    }
    public void testProjectBasicPattern() {