Re: seemingly useless #include recently added

On Tue, Apr 25, 2023 at 3:12 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Kyotaro Horiguchi <horikyota.ntt@gmail.com> writes:
> > While working on a patch, I noticed that a rcent commit (d4e71df6d75)
> > added an apparently unnecessary inclusion of guc.h in smgr.h.
>
> Yes, that seems quite awful, and I also wonder why it changed fd.h.
> Adding #include's to header files is generally not the first choice.

Agreed for smgr.h.  Will push when I'm back at a real computer soon,
or +1 from me if someone else wants to.  It must have been left over
from an earlier version that had a different arrangement with multiple
GUCs in different places and might have needed GUC-related types to
declare the check functions or something like that; sorry.  As for
fd.h, the reason it now includes <fcntl.h> is that fd.h tests whether
O_DIRECT is defined, so in fact that was an omission from 2dbe8905
which moved the #if defined(O_DIRECT) stuff from xlogdefs.h to fd.h
but failed to move the #include with it; I will check if something
needs to be back-patched there.