Fixing assorted potential problems raised by scan

* encoding.c parser.c relaxng.c runsuite.c tree.c xmlreader.c
  xmlschemas.c: nothing really serious but better safe than sorry

encoding.c

@@ -1414,7 +1414,7 @@ xmlCleanupCharEncodingHandlers(void) {
 void
 xmlRegisterCharEncodingHandler(xmlCharEncodingHandlerPtr handler) {
     if (handlers == NULL) xmlInitCharEncodingHandlers();
-    if (handler == NULL) {
+    if ((handler == NULL) || (handlers == NULL)) {
         xmlEncodingErr(XML_I18N_NO_HANDLER,
 		"xmlRegisterCharEncodingHandler: NULL handler !\n", NULL);
 	return;

parser.c

@@ -250,14 +250,15 @@ xmlErrAttributeDup(xmlParserCtxtPtr ctxt, const xmlChar * prefix,
 	return;
     if (ctxt != NULL)
 	ctxt->errNo = XML_ERR_ATTRIBUTE_REDEFINED;
+
     if (prefix == NULL)
         __xmlRaiseError(NULL, NULL, NULL, ctxt, NULL, XML_FROM_PARSER,
-                        ctxt->errNo, XML_ERR_FATAL, NULL, 0,
+                        XML_ERR_ATTRIBUTE_REDEFINED, XML_ERR_FATAL, NULL, 0,
                         (const char *) localname, NULL, NULL, 0, 0,
                         "Attribute %s redefined\n", localname);
     else
         __xmlRaiseError(NULL, NULL, NULL, ctxt, NULL, XML_FROM_PARSER,
-                        ctxt->errNo, XML_ERR_FATAL, NULL, 0,
+                        XML_ERR_ATTRIBUTE_REDEFINED, XML_ERR_FATAL, NULL, 0,
                         (const char *) prefix, (const char *) localname,
                         NULL, 0, 0, "Attribute %s:%s redefined\n", prefix,
                         localname);
@@ -555,14 +556,20 @@ xmlValidityError(xmlParserCtxtPtr ctxt, xmlParserErrors error,
 	if ((ctxt->sax != NULL) && (ctxt->sax->initialized == XML_SAX2_MAGIC))
 	    schannel = ctxt->sax->serror;
     }
-    __xmlRaiseError(schannel,
+    if (ctxt != NULL) {
+        __xmlRaiseError(schannel,
                     ctxt->vctxt.error, ctxt->vctxt.userData,
                     ctxt, NULL, XML_FROM_DTD, error,
                     XML_ERR_ERROR, NULL, 0, (const char *) str1,
 		    (const char *) str2, NULL, 0, 0,
 		    msg, (const char *) str1, (const char *) str2);
-    if (ctxt != NULL) {
 	ctxt->valid = 0;
+    } else {
+        __xmlRaiseError(schannel, NULL, NULL,
+                    ctxt, NULL, XML_FROM_DTD, error,
+                    XML_ERR_ERROR, NULL, 0, (const char *) str1,
+		    (const char *) str2, NULL, 0, 0,
+		    msg, (const char *) str1, (const char *) str2);
     }
 }
 
@@ -12500,7 +12507,9 @@ xmlParseExternalEntityPrivate(xmlDocPtr doc, xmlParserCtxtPtr oldctxt,
      * Record in the parent context the number of entities replacement
      * done when parsing that reference.
      */
-    oldctxt->nbentities += ctxt->nbentities;
+    if (oldctxt != NULL)
+        oldctxt->nbentities += ctxt->nbentities;
+
     /*
      * Also record the size of the entity parsed
      */

relaxng.c

@@ -5363,7 +5363,7 @@ xmlRelaxNGParseNameClass(xmlRelaxNGParserCtxtPtr ctxt, xmlNodePtr node,
     } else {
         xmlRngPErr(ctxt, node, XML_RNGP_CHOICE_CONTENT,
                    "expecting name, anyName, nsName or choice : got %s\n",
-                   node->name, NULL);
+                   (node == NULL ? 'nothing' : node->name), NULL);
         return (NULL);
     }
     if (ret != def) {
@@ -9442,7 +9442,11 @@ xmlRelaxNGValidateInterleave(xmlRelaxNGValidCtxtPtr ctxt,
             xmlRelaxNGFreeStates(ctxt, ctxt->states);
             ctxt->states = NULL;
             if (found == 0) {
-                VALID_ERR2(XML_RELAXNG_ERR_INTEREXTRA, cur->name);
+                if (cur == NULL) {
+                    VALID_ERR2(XML_RELAXNG_ERR_INTEREXTRA, 'noname');
+                } else {
+                    VALID_ERR2(XML_RELAXNG_ERR_INTEREXTRA, cur->name);
+                }
                 ret = -1;
                 ctxt->state = oldstate;
                 goto done;

runsuite.c

@@ -307,7 +307,7 @@ getString(xmlNodePtr cur, const char *xpath) {
  *									*
  ************************************************************************/
 
-static int 
+static int
 xsdIncorectTestCase(xmlNodePtr cur) {
     xmlNodePtr test;
     xmlBufferPtr buf;
@@ -319,7 +319,7 @@ xsdIncorectTestCase(xmlNodePtr cur) {
     if (cur == NULL) {
         return(0);
     }
-    
+
     test = getNext(cur, "./*");
     if (test == NULL) {
         test_log("Failed to find test in correct line %ld\n",

tree.c

@@ -1801,7 +1801,7 @@ xmlNewPropInternal(xmlNodePtr node, xmlNsPtr ns,
     cur = (xmlAttrPtr) xmlMalloc(sizeof(xmlAttr));
     if (cur == NULL) {
         if ((eatname == 1) &&
-	    ((node->doc == NULL) ||
+	    ((node == NULL) || (node->doc == NULL) ||
 	     (!(xmlDictOwns(node->doc->dict, name)))))
             xmlFree((xmlChar *) name);
         xmlTreeErrMemory("building attribute");
@@ -1861,8 +1861,8 @@ xmlNewPropInternal(xmlNodePtr node, xmlNsPtr ns,
         }
     }
 
-    if ((value != NULL) &&
-        (xmlIsID((node == NULL) ? NULL : node->doc, node, cur) == 1))
+    if ((value != NULL) && (node != NULL) &&
+        (xmlIsID(node->doc, node, cur) == 1))
         xmlAddID(NULL, node->doc, value, cur);
 
     if ((__xmlRegisterCallbacks) && (xmlRegisterNodeDefaultValue))
@@ -7779,8 +7779,11 @@ xmlDOMWrapStoreNs(xmlDocPtr doc,
 	}
     }
     /* Create. */
-    ns->next = xmlNewNs(NULL, nsName, prefix);
-    return (ns->next);
+    if (ns != NULL) {
+        ns->next = xmlNewNs(NULL, nsName, prefix);
+        return (ns->next);
+    }
+    return(NULL);
 }
 
 /*

xmlreader.c

@@ -1436,7 +1436,7 @@ get_next_node:
 	/*
 	 * Cleanup of the old node
 	 */
-	if ((reader->preserves == 0) &&
+	if ((oldnode != NULL) && (reader->preserves == 0) &&
 #ifdef LIBXML_XINCLUDE_ENABLED
 	    (reader->in_xinclude == 0) &&
 #endif

xmlschemas.c

@@ -6797,7 +6797,7 @@ xmlSchemaParseWildcardNs(xmlSchemaParserCtxtPtr ctxt,
 		    tmp->next = NULL;
 		    if (wildc->nsSet == NULL)
 			wildc->nsSet = tmp;
-		    else
+		    else if (lastNs != NULL)
 			lastNs->next = tmp;
 		    lastNs = tmp;
 		}
@@ -23721,12 +23721,14 @@ xmlSchemaBubbleIDCNodeTables(xmlSchemaValidCtxtPtr vctxt)
 		parBind->dupls = bind->dupls;
 		bind->dupls = NULL;
 	    }
-	    if (*parTable == NULL)
-		*parTable = parBind;
-	    else {
-		parBind->next = *parTable;
-		*parTable = parBind;
-	    }
+            if (parTable != NULL) {
+                if (*parTable == NULL)
+                    *parTable = parBind;
+                else {
+                    parBind->next = *parTable;
+                    *parTable = parBind;
+                }
+            }
 	}
 next_binding: