The bug has been fixed in the latest snapshot [1]. You'll now get an empty string instead (caused by the facts that the in-memory database node neither has a document node nor has a path that could be referenced).

Thanks, Christian

[1] http://files.basex.org/releases/latest

On Tue, Apr 21, 2015 at 4:27 PM, Christian Grün christian.gruen@gmail.com wrote:

Thanks for the stack trace. Obviously, db:path() shouldn't trigger an error. Instead, I guess it should return an empty string. I'll check this out.

On Tue, Apr 21, 2015 at 4:23 PM, cmarchand@oxiane.com wrote:

...

Hello,

I have this error. According to http://docs.basex.org/wiki/Database_Module#Database_Nodes, I thought modify() was transforming a node to a database node

It seems it does not initialize a document name...

Best regards,

Christophe

Error: Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk@mailman.uni-konstanz.de Version: BaseX 8.1 Java: Oracle Corporation, 1.8.0_31 OS: Windows 7, amd64 Stack Trace: java.lang.NullPointerException at org.basex.query.value.item.Str.get(Str.java:49) at org.basex.query.func.db.DbPath.item(DbPath.java:23) at org.basex.query.expr.ParseExpr.value(ParseExpr.java:64) at org.basex.query.QueryContext.value(QueryContext.java:415) at org.basex.query.up.expr.Transform.value(Transform.java:91) at org.basex.query.up.expr.Transform.iter(Transform.java:59) at org.basex.query.up.expr.Transform.iter(Transform.java:25) at org.basex.query.MainModule.iter(MainModule.java:114) at org.basex.query.QueryContext.iter(QueryContext.java:343) at org.basex.query.QueryContext.execute(QueryContext.java:605) at org.basex.query.QueryProcessor.execute(QueryProcessor.java:98) at org.basex.core.cmd.AQuery.query(AQuery.java:83) at org.basex.core.cmd.XQuery.run(XQuery.java:22) at org.basex.core.Command.run(Command.java:379) at org.basex.core.Command.execute(Command.java:95) at org.basex.gui.GUI.exec(GUI.java:466) at org.basex.gui.GUI.access$400(GUI.java:41) at org.basex.gui.GUI$7.run(GUI.java:410) Query: copy $c := <test/> modify () return db:path($c) Query plan:

<QueryPlan compiled="true"> <Transform> <Let> <Var name="$c" id="0" as="node()"/> <CElem> <QNm value="test" type="xs:QName"/> </CElem> </Let> <Empty size="0"/> <DbPath name="path(node)"> <VarRef> <Var name="$c" id="0" as="node()"/> </VarRef> </DbPath> </Transform> </QueryPlan>