Fix handling of XML-1.0 XML namespace declaration

Usually 'xml' namespace for XML-1.0 declaration does not need
to be carried but Mike Hommey raised the problem that the SVG
XSD file fails to parse due to a mishandling.
- SAX2.c: failure to create a namespace should not be interpreted
  as a memory allocation error
- tree.c: document better xmlNewNs behaviour, and fix it in the
  case the 'xml' prefix is being used.

1 files changed, 6 insertions, 2 deletions

diff --git a/SAX2.c b/SAX2.c
index 84c1f004..c0482c0b 100644
--- a/SAX2.c
+++ b/SAX2.c
@@ -2242,8 +2242,12 @@ xmlSAX2StartElementNs(void *ctx,
 	    if ((URI != NULL) && (prefix == pref))
 		ret->ns = ns;
 	} else {
-	    xmlSAX2ErrMemory(ctxt, "xmlSAX2StartElementNs");
-	    return;
+            /*
+             * any out of memory error would already have been raised
+             * but we can't be garanteed it's the actual error due to the
+             * API, best is to skip in this case
+             */
+	    continue;
 	}
 #ifdef LIBXML_VALID_ENABLED
 	if ((!ctxt->html) && ctxt->validate && ctxt->wellFormed &&