Re: [PATCH] Fix segfault calling PQflush on invalid connection

Daniele Varrazzo <daniele(dot)varrazzo(at)gmail(dot)com> writes:
> After exercising most of the libpq API in psycopg 3, PQflush() seems
> the only one requiring a guard [1]. All the other functions seem to
> behave well when passed an "invalid connection" - aka either a NULL
> pointer or a connection in BAD status.

I went so far as to inspect every function listed in libpq/exports.txt.
All the ones that take a PGconn or PGresult check it for NULL except

PQflush
PQisnonblocking
PQdefaultSSLKeyPassHook_OpenSSL

PQisnonblocking is clearly an oversight, same as PQflush.
Maybe there is a case for not bothering to check in
PQdefaultSSLKeyPassHook_OpenSSL, on the grounds that you'd
not get that far without a connection, but I think for
consistency it should do so too.

There is not a lot of consistency about whether we insist on
the connection being in any particular "good" state. For
some of the functions I think it's intentional that they should
still work on a failed connection, but I wonder if any of those
are likewise oversights.

regards, tom lane