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 11a5d706fd8507a4c22e45fbaf6c9ace7d7541e1..f36aab899a4fa144b248b12b398f32b227da2335 100644 (file)
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -1697,7 +1697,10 @@ 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.