cool#11320 xmloff: warn, but not fail when can't export a numbering style

It's not clear how to reproduce this problem, but when it happens, an
ODT file can't be saved because of an unhandled exception while
producing styles.xml.

Digging deeper, a container::NoSuchElementException is thrown in
XStyleFamily::getByName(), and when that happens the backtrace is:
	#0  (anonymous namespace)::XStyleFamily::getByName (this=0x28fb8740, rName=...)
	    at sw/source/core/unocore/unostyle.cxx:1031
	#1  0x000075ae461d5d8c in (anonymous namespace)::XStyleFamily::getByIndex (this=0x28fb8740, nIndex=0)
	    at sw/source/core/unocore/unostyle.cxx:1027
	#2  0x000075ae541c4d77 in XMLTextListAutoStylePool::XMLTextListAutoStylePool (this=0x75ae243c1318, rExp=...)
	    at include/com/sun/star/uno/Reference.h:384
I.e. the XMLTextListAutoStylePool gets the NumberingStyles style family,
nStyles is 15, we try to get each numbering style by index, but already
the first fails, because 0 gets turned into a 'Keine Liste' (no list)
name, but getting that internally by name then fails.

Fix the direct problem by catching container::NoSuchElementException in
the XMLTextListAutoStylePool_Impl ctor, not expoting a list style is
better than not being able to save the document at all.

Almost certainly this is an effect of a problem earlier, but this should
improve things till reproducer steps are found for that problem.

Change-Id: Ia9fbe8db9dfe5f90f2583111c3d59b98a914798d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/183402
Tested-by: Jenkins CollaboraOffice <[email protected]>
Reviewed-by: Andras Timar <[email protected]>

Author: vmiklos

xmloff/source/text/XMLTextListAutoStylePool.cxx

@@ -174,7 +174,14 @@ XMLTextListAutoStylePool::XMLTextListAutoStylePool( SvXMLExport& rExp ) :
     for (sal_Int32 i = 0; i < nStyles; i++)
     {
         Reference<XStyle> xStyle;
-        xStyles->getByIndex(i) >>= xStyle;
+        try
+        {
+            xStyles->getByIndex(i) >>= xStyle;
+        }
+        catch (const container::NoSuchElementException&)
+        {
+            SAL_WARN("xmloff", "XMLTextListAutoStylePool_Impl ctor: can't export numbering style #" << i);
+        }
         RegisterName(xStyle->getName());
     }
 }