On Wed, 2021-06-30 at 11:03 -0400, Tom Lane wrote:
> It does not look to me like json_errdetail can sensibly be used in
> frontend, since it returns palloc'd strings in some paths and
> constants in others. There'd be no way to avoid a memory leak
> in a frontend usage. So I think the dependency on psprintf there
> is not really a problem, but maybe we should make the entire function
> "#ifndef FRONTEND" to clarify the intended usage and avoid building
> useless code into clients.
FWIW this is one of the fixes (patch 0002) in the JSON-for-libpq thread
[1]. It ensures that all returned error strings are freeable by the
caller. That in turn was the impetus for the asprintf port suggestion.
But until/unless that is changed, an #ifndef seems like a good way to
prevent issues for the current code.
--Jacob
[1] https://www.postgresql.org/message-id/flat/a250d475ba1c0cc0efb7dfec8e538fcc77cdcb8e.camel@vmware.com