Lucene indexing fails if expression attribute contains self::* or function is called with self::* or . (dot)

[daliboris]

Describe the bug
When Lucene's field @expression attribute is equal to self::* or contains self::* somewhere in the XPath expression, indexation fails with no error in the log.

When Lucene's field @expression attribute contains call of the function from the imported module (like nav:get-metadata(self::*, 'module-dot')), first argument is defined as element() and XPath expression with self::* is used for that argument, an error is thrown: ERROR XPTY0004: The actual cardinality for parameter 1 does not match the cardinality declared in the function's signature: idx:get-metadata($root as element(), $field as xs:string) as item()*. Expected cardinality: exactly one, got 0.

When dot (.) is used as a value of the first argument, the nav:get-metadata(., 'module-dot')]: err:XPTY0004 element()(entry-orth) is not a sub-type of element() [at line 4, column 18, source: String/6014374732715299956] is thrown (dot is interpreted as a string, not element node).

Expected behavior
XPath expressions containing self::* are well formed, they should be evaluated and content should be indexed like in the cases when the element name or dot is used in XPath expression, ie. self::tei:name or ..

The same behavior is expected when function is called and XPath expression in the parameter represents current node via . (dot).

To Reproduce

xquery version "3.1";
module namespace t="http://exist-db.org/xquery/test";
declare namespace test="http://exist-db.org/xquery/xqsuite";
declare namespace tei="http://www.tei-c.org/ns/1.0";
declare namespace exist = "http://exist.sourceforge.net/NS/exist";

declare variable $t:XML := document { 
 <entry xmlns="http://www.tei-c.org/ns/1.0"><form><orth>entry-orth</orth></form></entry>
};


declare variable $t:xconf :=
<collection xmlns="http://exist-db.org/collection-config/1.0">
    <index xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:tei="http://www.tei-c.org/ns/1.0">
        <lucene>
            <module uri="http://teipublisher.com/index" prefix="nav" at="index.xql" />
            <text qname="tei:entry">
                <!-- expressions -->
                <field name="expression-dot" expression="." /> <!-- works -->
                <field name="expression-self-name" expression="self::tei:entry" /> <!-- works -->
                <field name="expression-dot-self-asterisk" expression="./self::*" /> <!-- fails -->
                <field name="expression-dot-self-asterisk-child" expression="./self::*/tei:form" /> <!-- fails -->
                <field name="expression-self-asterisk" expression="self::*" /> <!-- fails -->
                <field name="expression-asterisk" expression="*" /> <!-- works -->
                <field name="expression-dot-asterisk" expression="./*" /> <!-- works -->
                <!-- module function calls -->
                <field name="module-dot" expression="nav:get-metadata(., 'module-dot')" /> <!-- fails -->
                <field name="module-self-name" expression="nav:get-metadata(self::tei:entry, 'module-self-name')" /> <!-- fails -->
                <field name="module-self-asterisk" expression="nav:get-metadata(self::*, 'module-self-asterisk')" /> <!-- fails -->
                <field name="module-dot-self-asterisk" expression="nav:get-metadata(./self::*, 'module-dot-self-asterisk')" /> <!-- fails -->
                <field name="module-dot-self-asterisk-child" expression="nav:get-metadata(./self::*/tei:form, 'module-dot-self-asterisk-child')" /> <!-- fails -->
                <field name="module-asterisk" expression="nav:get-metadata(*, 'module-asterisk')" /> <!-- fails -->
                <field name="module-dot-asterisk" expression="nav:get-metadata(./*, 'module-dot-asterisk')" /> <!-- fails -->
            </text>
        </lucene>
    </index>
</collection>;


declare variable $t:module := 'xquery version "3.1";

module namespace idx="http://teipublisher.com/index";
declare function idx:get-metadata($root as element(), $field as xs:string) {
    $field || ":" || normalize-space($root)
};';

declare variable $t:testCol := xmldb:create-collection("/db", "test");
declare variable $t:indexCol := xmldb:create-collection("/db/system/config/db", "test");


declare
    %test:setUp
function t:setup() {
        (
            xmldb:store($t:testCol, "index.xql", $t:module),
            xmldb:store($t:testCol, "test.xml", $t:XML),
            xmldb:store($t:indexCol, "collection.xconf", $t:xconf),
            xmldb:reindex("/db/test")
        )
};

declare
    %test:tearDown
function t:tearDown() {
    if (xmldb:collection-available($t:testCol)) then xmldb:remove($t:testCol) else (),
    if (xmldb:collection-available($t:indexCol)) then xmldb:remove($t:indexCol) else ()
};

(: expressions tests :)

declare 
%test:args("expression-dot") %test:assertEquals(1)
function t:expression-dot($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("expression-self-name") %test:assertEquals(1)
function t:expression-self-name($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("expression-self-asterisk") %test:assertEquals(1)
function t:expression-self-asterisk($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("expression-dot-self-asterisk") %test:assertEquals(1)
function t:expression-dot-self-asterisk($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("expression-dot-self-asterisk-child") %test:assertEquals(1)
function t:expression-dot-self-asterisk-child($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("expression-asterisk") %test:assertEquals(1)
function t:expression-asterisk($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("expression-dot-asterisk") %test:assertEquals(1)
function t:expression-dot-asterisk($field-name as xs:string) {
    t:get-field-index($field-name) 
};

(: module function calls tests :)

declare 
%test:args("module-dot") %test:assertEquals(1)
function t:module-dot($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("module-self-name") %test:assertEquals(1)
function t:module-self-name($field-name as xs:string) {
    t:get-field-index($field-name) 
};


declare 
%test:args("module-self-asterisk") %test:assertEquals(1)
function t:module-self-asterisk($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("module-dot-self-asterisk") %test:assertEquals(1)
function t:module-dot-self-asterisk($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("module-dot-self-asterisk-child") %test:assertEquals(1)
function t:module-dot-self-asterisk-child($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("module-asterisk") %test:assertEquals(1)
function t:module-asterisk($field-name as xs:string) {
    t:get-field-index($field-name) 
};

declare 
%test:args("module-dot-asterisk") %test:assertEquals(1)
function t:module-dot-asterisk($field-name as xs:string) {
    t:get-field-index($field-name) 
};


declare
function t:get-field-index($field-name as xs:string) {
    let $query-options := "map { 'leading-wildcard': 'yes', 'filter-rewrite': 'yes' }"
    let $field-to-retrieve := "ft:field(., '" || $field-name || "')"
    let $nodeset := 'collection("' || $t:testCol || '")//tei:entry'
    let $field-query := "[ft:query(., '" || $field-name || ":(*)', " || $query-options || ")] "
    let $namespace := 'declare namespace tei="http://www.tei-c.org/ns/1.0";' || "&#xa;"
    let $query := $namespace || $nodeset || $field-query || " ! " || $field-to-retrieve

    (: 
    example of created query string
    declare namespace tei="http://www.tei-c.org/ns/1.0"; 
    collection("/db/apps/test")//tei:entry[ft:query(., 
        'match-dot:(*)', 
        map { 'leading-wildcard': 'yes', 'filter-rewrite': 'yes' })
        ] 
        ! ft:field(., 'match-dot')
    :)
    let $result :=  util:eval($query)
    return count($result)
};

Context (please always complete the following information)

• Build: eXist-7.0.0-SNAPSHOT (dce395f)
• Java: 21.0.11 (Eclipse Adoptium)
• OS: Linux 5.15.167.4-microsoft-standard-WSL2 (amd64)