On Mon, Dec 03, 2012 at 01:14:30PM -0500, Andrew Dunstan wrote:
> I think it would be reasonable for it to complain if it came across a
> PG_VERSION file in an unexpected location.
That sounds like a reliable approach to detecting the hazard. Pseudocode:
chdir(proposed_tablespace_path)do { if (stat("PG_VERSION")) ereport(WARNING, ...)} while (chdir(".."))