[xslt] Segmentation fault fixed but still no cigar

[Teppo Peltonen <tpeltone cc hut fi>]

Hello Daniel,

Thank you very much for implementing the parameter passing mechanism
for xsltproc.

However, I still can get my stylesheet working with libxslt. Below you
can find the the minimal test case for the bug. Also, I have included
the fix to get around the segfaults, but I'm afraid that it only is
hiding the real problem which I am unable to grasp at this time... ;-)

Bye, going to get some sleep now,

Teppo

------------------------------------------------------------

[teppo ahven /tmp]$ xsltproc bug.xsl bug.xsl 
unregistered variable b
unregistered variable b
xmlXPathEval: evaluation failed
xsltDefaultProcessOneNode: text copy failed
Segmentation fault (core dumped)
[teppo ahven /tmp]$ 

------------------------------------------------------------

<?xml version="1.0" ?> 

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
                 version="1.0">

<xsl:variable name="a">
   <xsl:variable name="b" select="'Hello'"/>
   <xsl:value-of select="$b"/>
</xsl:variable>

<xsl:template match="/">
   <xsl:value-of select="$a"/>
</xsl:template>

</xsl:stylesheet>

------------------------------------------------------------

--- libxml2-2.3.6-orig/xpath.c	Sun Apr  8 05:35:06 2001
+++ libxml2-2.3.6/xpath.c	Sun Apr 15 06:06:35 2001
@@ -7079,7 +7079,9 @@
 	    /*
 	     * Hum are we filtering the result of an XPointer expression
 	     */
-	    if (ctxt->value->type == XPATH_LOCATIONSET) {
+	    if (ctxt->value != NULL 
+                && ctxt->value->type == XPATH_LOCATIONSET) {
+
 		xmlLocationSetPtr newlocset = NULL;
 		xmlLocationSetPtr oldlocset;
 
--- libxslt-0.7.0-orig/libxslt/transform.c	Sun Apr  8 05:55:06 2001
+++ libxslt-0.7.0/libxslt/transform.c	Sun Apr 15 06:11:58 2001
@@ -2429,15 +2429,19 @@
     }
 
 #ifdef DEBUG_PROCESS
-    xsltGenericDebug(xsltGenericDebugContext,
-	"xsltForEach: select evaluate to %d nodes\n", list->nodeNr);
+    if (list != NULL) {
+            xsltGenericDebug(xsltGenericDebugContext,
+              "xsltForEach: select evaluate to %d nodes\n", list->nodeNr);
+    }
 #endif
 
     oldlist = ctxt->nodeList;
     ctxt->nodeList = list;
     oldContextSize = ctxt->xpathCtxt->contextSize;
     oldProximityPosition = ctxt->xpathCtxt->proximityPosition;
-    ctxt->xpathCtxt->contextSize = list->nodeNr;
+    if (list != NULL) {
+            ctxt->xpathCtxt->contextSize = list->nodeNr;
+    }
 
     /* 
      * handle and skip the xsl:sort
@@ -2448,7 +2452,7 @@
 	replacement = replacement->next;
     }
 
-    for (i = 0;i < list->nodeNr;i++) {
+    for (i = 0;list != NULL && i < list->nodeNr;i++) {
 	ctxt->node = list->nodeTab[i];
 	ctxt->xpathCtxt->proximityPosition = i + 1;
 	/* ctxt->insert = oldInsert; */
--- libxslt-0.7.0-orig/libxslt/variables.c	Tue Apr  3 05:55:06 2001
+++ libxslt-0.7.0/libxslt/variables.c	Sun Apr 15 06:02:52 2001
@@ -145,8 +145,10 @@
     if ((ctxt == NULL) || (elem == NULL))
 	return(-1);
 
-    elem->next = ctxt->varsTab[ctxt->varsNr - 1];
-    ctxt->varsTab[ctxt->varsNr - 1] = elem;
+    if (ctxt->varsNr > 0) {
+            elem->next = ctxt->varsTab[ctxt->varsNr - 1];
+            ctxt->varsTab[ctxt->varsNr - 1] = elem;
+    }
     ctxt->vars = elem;
     return(0);
 }

------------------------------------------------------------


-- 
if (status = UNDER_NUCLEAR_ATTACK) { launch_all_missiles(); } /* B. Godfrey */