[refactor] Change the XQuery implementation defined behaviour for "Default order for empty sequences" to "empty least", so it matches the approach taken by Saxon and BaseX. IMHO "empty least" is also more likely the 'expected' behaviour.

Author: adamretter

exist-core/pom.xml

@@ -751,6 +751,7 @@
                                 <exclude>src/test/java/org/exist/xquery/value/SubSequenceRangeTest.java</exclude>
                                 <exclude>src/test/java/org/exist/xquery/value/SubSequenceTest.java</exclude>
                                 <exclude>src/test/xquery/binary-value.xqm</exclude>
+                                <exclude>src/test/xquery/order.xqm</exclude>
 
                                 <!--
                                     Derivative work licensed under dbXML 1.0 and LGPL 2.1
@@ -901,6 +902,7 @@ The original license statement is also included below.]]></preamble>
                                 <include>src/test/java/org/exist/xquery/value/SubSequenceRangeTest.java</include>
                                 <include>src/test/java/org/exist/xquery/value/SubSequenceTest.java</include>
                                 <include>src/test/xquery/binary-value.xqm</include>
+                                <include>src/test/xquery/order.xqm</include>
                             </includes>
 
                         </licenseSet>

exist-core/src/main/java/org/exist/xquery/XQueryContext.java

@@ -320,7 +320,7 @@ public class XQueryContext implements BinaryValueManager, Context {
     /**
      * Should empty order greatest or least?
      */
-    private boolean orderEmptyGreatest = true;
+    private boolean orderEmptyGreatest = false;
 
     /**
      * XQuery 3.0 - declare context item :=

exist-core/src/test/xquery/order.xqm

@@ -0,0 +1,89 @@
+(:
+ : Copyright (C) 2014, Evolved Binary Ltd
+ :
+ : This file was originally ported from FusionDB to eXist-db by
+ : Evolved Binary, for the benefit of the eXist-db Open Source community.
+ : Only the ported code as it appears in this file, at the time that
+ : it was contributed to eXist-db, was re-licensed under The GNU
+ : Lesser General Public License v2.1 only for use in eXist-db.
+ :
+ : This license grant applies only to a snapshot of the code as it
+ : appeared when ported, it does not offer or infer any rights to either
+ : updates of this source code or access to the original source code.
+ :
+ : The GNU Lesser General Public License v2.1 only license follows.
+ :
+ : ---------------------------------------------------------------------
+ :
+ : Copyright (C) 2014, Evolved Binary Ltd
+ :
+ : This library is free software; you can redistribute it and/or
+ : modify it under the terms of the GNU Lesser General Public
+ : License as published by the Free Software Foundation; version 2.1.
+ :
+ : This library is distributed in the hope that it will be useful,
+ : but WITHOUT ANY WARRANTY; without even the implied warranty of
+ : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ : Lesser General Public License for more details.
+ :
+ : You should have received a copy of the GNU Lesser General Public
+ : License along with this library; if not, write to the Free Software
+ : Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ :)
+xquery version "1.0";
+
+module namespace ord = "http://exist-db.org/test/order";
+
+declare namespace test = "http://exist-db.org/xquery/xqsuite";
+
+declare variable $ord:items as element(item)+ := (
+        <item>
+         <ref>e1</ref>
+         <msDesc type="Ll"/>
+        </item>
+        ,
+        <item>
+         <ref>e2</ref>
+         <msDesc type="P"/>
+        </item>
+        ,
+        <item>
+         <ref>e3</ref>
+         <msDesc type="Ll"/>
+        </item>
+        ,
+        <item>
+         <ref>e4</ref>
+         <msDesc/>
+        </item>
+);
+
+declare
+    %test:assertEquals("e2", "e1", "e3", "e4")
+function ord:default-order-for-empty-sequence-is-empty-least() {
+    for $item in $ord:items
+    let $sort-condition as xs:boolean? := $item/msDesc/@type eq 'P'
+    order by $sort-condition descending
+    return
+        $item/ref/string()
+};
+
+declare
+    %test:assertEquals("e2", "e1", "e3", "e4")
+function ord:order-empty-sequence-as-empty-least() {
+    for $item in $ord:items
+    let $sort-condition as xs:boolean? := $item/msDesc/@type eq 'P'
+    order by $sort-condition descending empty least
+    return
+        $item/ref/string()
+};
+
+declare
+    %test:assertEquals("e4", "e2", "e1", "e3")
+function ord:order-empty-sequence-as-empty-greatest() {
+    for $item in $ord:items
+    let $sort-condition as xs:boolean? := $item/msDesc/@type eq 'P'
+    order by $sort-condition descending empty greatest
+    return
+        $item/ref/string()
+};