[libxml2] Fix regression introduced with commit 74dcc10b

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 87d20b554c6a90e7ece1cc7391c005089bf85b78
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Wed Aug 19 13:52:08 2020 +0200

    Fix regression introduced with commit 74dcc10b
    
    The code wasn't dead after all, but I can see no reason in delaying
    the XPointer evaluation. This could lead to nodes included earlier
    appearing in XPointer results.

 result/XInclude/ns1.xml     | 10 ++++++++++
 result/XInclude/ns1.xml.rdr | 23 +++++++++++++++++++++++
 test/XInclude/docs/ns1.xml  | 12 ++++++++++++
 xinclude.c                  |  2 +-
 4 files changed, 46 insertions(+), 1 deletion(-)
---
diff --git a/result/XInclude/ns1.xml b/result/XInclude/ns1.xml
new file mode 100644
index 000000000..ab41fb7a9
--- /dev/null
+++ b/result/XInclude/ns1.xml
@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<doc xmlns:xi="http://www.w3.org/2001/XInclude";>
+    <ns:elem xmlns:ns="urn:foo" xml:id="a"/>
+    <elem xmlns:ns="urn:foo">
+        <ns:elem xml:id="a"/>
+    </elem>
+    
+            <ns:elem xmlns:ns="urn:bar"/>
+        
+</doc>
diff --git a/result/XInclude/ns1.xml.rdr b/result/XInclude/ns1.xml.rdr
new file mode 100644
index 000000000..f23702f57
--- /dev/null
+++ b/result/XInclude/ns1.xml.rdr
@@ -0,0 +1,23 @@
+0 1 doc 0 0
+1 14 #text 0 1 
+    
+1 1 ns:elem 1 0
+1 14 #text 0 1 
+    
+1 1 elem 0 0
+2 14 #text 0 1 
+        
+2 1 ns:elem 1 0
+2 14 #text 0 1 
+    
+1 15 elem 0 0
+1 14 #text 0 1 
+    
+1 14 #text 0 1 
+            
+1 1 ns:elem 1 0
+1 14 #text 0 1 
+        
+1 14 #text 0 1 
+
+0 15 doc 0 0
diff --git a/test/XInclude/docs/ns1.xml b/test/XInclude/docs/ns1.xml
new file mode 100644
index 000000000..7523f4a9f
--- /dev/null
+++ b/test/XInclude/docs/ns1.xml
@@ -0,0 +1,12 @@
+<?xml version="1.0"?>
+<doc xmlns:xi="http://www.w3.org/2001/XInclude";>
+    <xi:include href="#a"/>
+    <elem xmlns:ns="urn:foo">
+        <ns:elem xml:id="a"/>
+    </elem>
+    <xi:include href="b.xml">
+        <xi:fallback xmlns:ns="urn:bar">
+            <ns:elem/>
+        </xi:fallback>
+    </xi:include>
+</doc>
diff --git a/xinclude.c b/xinclude.c
index aac30d5b0..c92b32bc8 100644
--- a/xinclude.c
+++ b/xinclude.c
@@ -1464,7 +1464,7 @@ xmlXIncludeLoadDoc(xmlXIncludeCtxtPtr ctxt, const xmlChar *url, int nr) {
      */
     if ((URL[0] == 0) || (URL[0] == '#') ||
        ((ctxt->doc != NULL) && (xmlStrEqual(URL, ctxt->doc->URL)))) {
-       doc = NULL;
+       doc = ctxt->doc;
         goto loaded;
     }