[libxml2] Stop using XPATH_OP_RESET

[Nick Wellnhofer <nwellnhof src gnome org>]

commit e22a83b1d095dac25ce05e1a2d9f263f41d11c68
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Thu May 25 01:18:36 2017 +0200

    Stop using XPATH_OP_RESET
    
    It only sets the context node to NULL which doesn't seem useful and can
    even cause bugs like bug #795299:
    
    https://bugzilla.gnome.org/show_bug.cgi?id=795299

 xpath.c |   37 +++----------------------------------
 1 files changed, 3 insertions(+), 34 deletions(-)
---
diff --git a/xpath.c b/xpath.c
index bd09364..601763e 100644
--- a/xpath.c
+++ b/xpath.c
@@ -868,15 +868,14 @@ typedef enum {
     XPATH_OP_UNION,
     XPATH_OP_ROOT,
     XPATH_OP_NODE,
-    XPATH_OP_RESET, /* 10 */
     XPATH_OP_COLLECT,
-    XPATH_OP_VALUE, /* 12 */
+    XPATH_OP_VALUE, /* 11 */
     XPATH_OP_VARIABLE,
     XPATH_OP_FUNCTION,
     XPATH_OP_ARG,
     XPATH_OP_PREDICATE,
-    XPATH_OP_FILTER, /* 17 */
-    XPATH_OP_SORT /* 18 */
+    XPATH_OP_FILTER, /* 16 */
+    XPATH_OP_SORT /* 17 */
 #ifdef LIBXML_XPTR_ENABLED
     ,XPATH_OP_RANGETO
 #endif
@@ -1526,8 +1525,6 @@ xmlXPathDebugDumpStepOp(FILE *output, xmlXPathCompExprPtr comp,
             fprintf(output, "ROOT"); break;
         case XPATH_OP_NODE:
             fprintf(output, "NODE"); break;
-        case XPATH_OP_RESET:
-            fprintf(output, "RESET"); break;
         case XPATH_OP_SORT:
             fprintf(output, "SORT"); break;
         case XPATH_OP_COLLECT: {
@@ -10735,7 +10732,6 @@ xmlXPathCompPathExpr(xmlXPathParserContextPtr ctxt) {
 
            PUSH_LONG_EXPR(XPATH_OP_COLLECT, AXIS_DESCENDANT_OR_SELF,
                    NODE_TEST_TYPE, NODE_TYPE_NODE, NULL, NULL);
-           PUSH_UNARY_EXPR(XPATH_OP_RESET, ctxt->comp->last, 1, 0);
 
            xmlXPathCompRelativeLocationPath(ctxt);
        } else if (CUR == '/') {
@@ -12779,15 +12775,6 @@ xmlXPathCompOpEvalFirst(xmlXPathParserContextPtr ctxt,
            valuePush(ctxt, xmlXPathCacheNewNodeSet(ctxt->context,
                ctxt->context->node));
             return (total);
-        case XPATH_OP_RESET:
-            if (op->ch1 != -1)
-                total += xmlXPathCompOpEval(ctxt, &comp->steps[op->ch1]);
-           CHECK_ERROR0;
-            if (op->ch2 != -1)
-                total += xmlXPathCompOpEval(ctxt, &comp->steps[op->ch2]);
-           CHECK_ERROR0;
-            ctxt->context->node = NULL;
-            return (total);
         case XPATH_OP_COLLECT:{
                 if (op->ch1 == -1)
                     return (total);
@@ -12918,15 +12905,6 @@ xmlXPathCompOpEvalLast(xmlXPathParserContextPtr ctxt, xmlXPathStepOpPtr op,
            valuePush(ctxt, xmlXPathCacheNewNodeSet(ctxt->context,
                ctxt->context->node));
             return (total);
-        case XPATH_OP_RESET:
-            if (op->ch1 != -1)
-                total += xmlXPathCompOpEval(ctxt, &comp->steps[op->ch1]);
-           CHECK_ERROR0;
-            if (op->ch2 != -1)
-                total += xmlXPathCompOpEval(ctxt, &comp->steps[op->ch2]);
-           CHECK_ERROR0;
-            ctxt->context->node = NULL;
-            return (total);
         case XPATH_OP_COLLECT:{
                 if (op->ch1 == -1)
                     return (0);
@@ -13457,15 +13435,6 @@ xmlXPathCompOpEval(xmlXPathParserContextPtr ctxt, xmlXPathStepOpPtr op)
            valuePush(ctxt, xmlXPathCacheNewNodeSet(ctxt->context,
                ctxt->context->node));
             return (total);
-        case XPATH_OP_RESET:
-            if (op->ch1 != -1)
-                total += xmlXPathCompOpEval(ctxt, &comp->steps[op->ch1]);
-           CHECK_ERROR0;
-            if (op->ch2 != -1)
-                total += xmlXPathCompOpEval(ctxt, &comp->steps[op->ch2]);
-           CHECK_ERROR0;
-            ctxt->context->node = NULL;
-            return (total);
         case XPATH_OP_COLLECT:{
                 if (op->ch1 == -1)
                     return (total);