Describe XSLT parser errors in the exception message instead of using…

… rb_warn

All XSLT parser errors will be displayed in the exception message.

When we did an rb_raise from the callback, we only got the first parser error.
A nice side effect here is that we get all errors in the exception.

ext/nokogiri/xslt_stylesheet.c

@@ -26,7 +26,7 @@ static void xslt_generic_error_handler(void * ctx, const char *msg, ...)
   vasprintf(&message, msg, args);
   va_end(args);
 
-  rb_warning("%s", message);
+  rb_str_cat2((VALUE)ctx, message);
 
   vasprintf_free(message);
 }
@@ -40,11 +40,13 @@ static void xslt_generic_error_handler(void * ctx, const char *msg, ...)
 static VALUE parse_stylesheet_doc(VALUE klass, VALUE xmldocobj)
 {
     xmlDocPtr xml, xml_cpy;
+    VALUE errstr, exception;
     xsltStylesheetPtr ss ;
     Data_Get_Struct(xmldocobj, xmlDoc, xml);
     exsltRegisterAll();
 
-    xsltSetGenericErrorFunc(NULL, xslt_generic_error_handler);
+    errstr = rb_str_new(0, 0);
+    xsltSetGenericErrorFunc((void *)errstr, xslt_generic_error_handler);
 
     xml_cpy = xmlCopyDoc(xml, 1); /* 1 => recursive */
     ss = xsltParseStylesheetDoc(xml_cpy);
@@ -53,7 +55,8 @@ static VALUE parse_stylesheet_doc(VALUE klass, VALUE xmldocobj)
 
     if (!ss) {
 	xmlFreeDoc(xml_cpy);
-	rb_raise(rb_eRuntimeError, "Unable to Parse the XSLT Document.");
+	exception = rb_exc_new3(rb_eRuntimeError, errstr);
+	rb_exc_raise(exception);
     }
 
     return Data_Wrap_Struct(klass, NULL, dealloc, ss);

test/test_xslt_transforms.rb

@@ -175,10 +175,7 @@ def test_xslt_parse_error
   </xsl:template>
 </xsl:stylesheet>}
       EOX
-      old_verbose = $VERBOSE
-      $VERBOSE = false
       assert_raises(RuntimeError) { Nokogiri::XSLT.parse(xslt_str) }
-      $VERBOSE = old_verbose
     end
 
     def test_passing_a_non_document_to_transform