Thread: PG_CATCH used without PG_RETHROW

My understanding is that PG_TRY/PG_CATCH doesn't save enough state to
avoid rethrowing errors and if you want to actually continue the
transaction you must use a subtransaction. As a result I was under the
impression it was mandatory to PG_RETHROW as a result.

If that's the case then I think I just came across a bug in
utils/adt/xml.c where there's no PG_RETHROW:

/** Functions for checking well-formed-ness*/

#ifdef USE_LIBXML
static bool
wellformed_xml(text *data, XmlOptionType xmloption_arg)
{
bool result;
volatile xmlDocPtr doc = NULL;

/* We want to catch any exceptions and return false */
PG_TRY();
{
doc = xml_parse(data, xmloption_arg, true, GetDatabaseEncoding());
result = true;
}
PG_CATCH();
{
FlushErrorState();
result = false;
}
PG_END_TRY();

if (doc)
xmlFreeDoc(doc);

return result;
}
#endif

-- 
greg

Greg Stark <stark@mit.edu> writes:
> My understanding is that PG_TRY/PG_CATCH doesn't save enough state to
> avoid rethrowing errors and if you want to actually continue the
> transaction you must use a subtransaction. As a result I was under the
> impression it was mandatory to PG_RETHROW as a result.

> If that's the case then I think I just came across a bug in
> utils/adt/xml.c where there's no PG_RETHROW:

The reason we think that's OK is that we assume libxml2 does not call back
into the general backend code, so there is no PG state we'd have to undo.
        regards, tom lane