Defend against null error message reported by libxml2.

While this isn't really supposed to happen, it can occur in OOM
situations and perhaps others.  Instead of crashing, substitute
"(no message provided)".

I didn't worry about localizing this text, since we aren't
localizing anything else here; besides, if we're on the edge of
OOM, it's unlikely gettext() would work.

Report and fix by Sergio Conde Gómez in bug #15624.

Discussion: https://postgr.es/m/15624-4dea54091a2864e6@postgresql.org

diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 9d3b189c940bbf63c0ec8582e5bd3439b6b388c2..e78c2ab96bab04807641cbf59e385e9adf36c808 100644 (file)
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -1636,7 +1636,10 @@ xml_errorHandler(void *data, xmlErrorPtr error)
        appendStringInfo(errorBuf, "line %d: ", error->line);
    if (name != NULL)
        appendStringInfo(errorBuf, "element %s: ", name);
-   appendStringInfoString(errorBuf, error->message);
+   if (error->message != NULL)
+       appendStringInfoString(errorBuf, error->message);
+   else
+       appendStringInfoString(errorBuf, "(no message provided)");
 
    /*
     * Append context information to errorBuf.