Consider this XQuery:

declare namespace _="urn:_"; declare function _:query-index___($dict as xs:string, $ind as xs:string, $str as xs:string) {     let $rs :=     (# db:enforceindex #) {     switch ($ind)         case "any"             return                 collection($dict)//index/w[text() contains text { $str } using wildcards]         default return             if ($str = '*')             then                 collection($dict)//index[@id = $ind]/w             else                 collection($dict)//index[@id = $ind]/w[text() contains text { $str } using wildcards]     }     return $rs };

_:query-index___('dc_arz_eng_publ__ind', 'any', 'beer.*')

where dc_arz_eng_publ__ind contians a single XML which looks like (probably irrelevant):

<indices>   <index id="lem">     <w>-</w>     <w>mafṛama</w>     <w>without</w>   </index>   <index id="other">   </index> </indices>

There is a java.lang.ArrayIndexOutOfBoundsException:

Version: BaseX 9.7.2 Java: Azul Systems, Inc., 11.0.14.1 OS: Windows 10, amd64 Stack Trace: java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 8         at org.basex.query.var.QueryStack.get(QueryStack.java:99)         at org.basex.query.QueryContext.get(QueryContext.java:553)         at org.basex.query.var.VarRef.value(VarRef.java:46)         at org.basex.query.expr.ParseExpr.atomValue(ParseExpr.java:61)         at org.basex.query.expr.Expr.atomItem(Expr.java:116)         at org.basex.query.func.fn.Docs.collection(Docs.java:36)         at org.basex.query.func.fn.FnCollection.value(FnCollection.java:15)         at org.basex.query.expr.index.IndexDynDb.data(IndexDynDb.java:86)         at org.basex.query.expr.index.IndexDb.data(IndexDb.java:35)         at org.basex.query.expr.ft.FTWords.iter(FTWords.java:153)         at org.basex.query.expr.ft.FTIndexAccess.iter(FTIndexAccess.java:43)         at org.basex.query.expr.ft.FTIndexAccess.value(FTIndexAccess.java:63)         at org.basex.query.expr.path.CachedPath.nodes(CachedPath.java:43)         at org.basex.query.expr.path.AxisPath.value(AxisPath.java:41)         at org.basex.query.expr.Extension.value(Extension.java:59)         at org.basex.query.expr.ParseExpr.iter(ParseExpr.java:46)         at org.basex.query.expr.gflwor.For$1.next(For.java:112)         at org.basex.query.expr.gflwor.Let$LetEval.next(Let.java:144)         at org.basex.query.expr.gflwor.OrderBy$1.sort(OrderBy.java:73)         at org.basex.query.expr.gflwor.OrderBy$1.next(OrderBy.java:54)         at org.basex.query.expr.gflwor.GFLWOR$1.next(GFLWOR.java:68)         at org.basex.query.QueryContext.next(QueryContext.java:359)         at org.basex.query.expr.constr.Constr.add(Constr.java:73)         at org.basex.query.expr.constr.CElem.item(CElem.java:149)         at org.basex.query.expr.constr.CElem.item(CElem.java:1)         at org.basex.query.expr.ItemMap.item(ItemMap.java:29)         at org.basex.query.expr.ParseExpr.value(ParseExpr.java:51)         at org.basex.query.expr.ParseExpr.iter(ParseExpr.java:46)         at org.basex.query.scope.MainModule.iter(MainModule.java:60)         at org.basex.query.QueryContext.iter(QueryContext.java:338)         at org.basex.http.restxq.RestXqResponse.serialize(RestXqResponse.java:85)         at org.basex.http.web.WebResponse.create(WebResponse.java:58)         at org.basex.http.restxq.RestXqServlet.run(RestXqServlet.java:72)         at org.basex.http.BaseXServlet.service(BaseXServlet.java:69)         at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)         at org.eclipse.jetty.servlet.ServletHolder$NotAsync.service(ServletHolder.java:1450)         at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:799)         at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:550)         at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)         at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:600)         at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)         at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235)         at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624)         at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)         at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1440)         at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)         at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:501)         at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594)         at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)         at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1355)         at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)         at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)         at org.eclipse.jetty.server.Server.handle(Server.java:516)         at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:487)         at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:732)         at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:479)         at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277)         at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)         at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)         at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)         at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338)         at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315)         at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173)         at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131)         at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:409)         at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:883)         at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1034)         at java.base/java.lang.Thread.run(Thread.java:829)

If I don't use (# db:enforceindex #) {} it works as expected

Best regards