On 2013-01-14 22:26:39 -0500, Tom Lane wrote: > Andres Freund <and...@2ndquadrant.com> writes: > > On 2013-01-14 20:39:05 -0500, Peter Eisentraut wrote: > >> On Tue, 2013-01-15 at 00:29 +0100, Andres Freund wrote: > >>> Independently from this patch, should we add -Wtype-limits to the > >>> default parameters? > > >> I think we have had a discussion along this line before. I am against > >> fixing warnings from this option, because those changes would hide > >> errors if a variable's type changed from signed to unsigned or vice > >> versa, which could happen because of refactoring or it might be > >> dependent on system headers. > > > Well, I already found a bug (although with very limited consequences) in > > the walsender code and one with graver consequences in code I just > > submitted. So I don't really see that being on-par with some potential > > future refactoring... > > FWIW, I agree with Peter --- in particular, warning against "x >= MIN" > just because MIN happens to be zero and x happens to be unsigned is the > sort of nonsense up with which we should not put. Kowtowing to that > kind of warning makes the code less robust, not more so.
Oh, I agree, that warning is pointless in itself. But in general doing a comparison like > 0 *can* show a programming error as evidenced e.g. by http://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=3f4b1749a8168893558f70021be4f40c650bbada and just about the same error I made in xlogdump. I just think that the price of fixing a single Assert() that hasn't changed in years where the variable isn't likely to ever get signed is acceptable. > It's a shame that the compiler writers have not figured this out and > separated misguided pedantry from actually-useful warnings. If I assign > -1 to an unsigned variable, by all means tell me about *that*. Don't > tell me your opinion of whether an assertion check is necessary. Yea, but I have to admit its damned hard hard to automatically discern the above actually valid warning and the bogus Assert... Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
