Re: Ordering of header file inclusion

On Tue, Oct 8, 2019 at 8:19 PM Tom Lane  wrote:
>
> Amit Kapila  writes:
> > On Wed, Oct 2, 2019 at 2:57 PM vignesh C  wrote:
> >> I noticed that some of the header files inclusion is not ordered as
> >> per the usual standard that is followed.
> >> The attached patch contains the fix for the order in which the header
> >> files are included.
> >> Let me know your thoughts on the same.
>
> > +1.
>
> FWIW, I'm not on board with reordering system-header inclusions.
> Some platforms have (had?) ordering dependencies for those, and where
> that's true, it's seldom alphabetical.  It's only our own headers
> where we can safely expect that any arbitrary order will work.
>

Okay, that makes sense.  However, I noticed that ordering for
system-header inclusions is somewhat random.  For ex. nodeSubPlan.c,
datetime.c, etc. include limits.h first and then math.h whereas
knapsack.c, float.c includes them in reverse order.  There could be
more such inconsistencies and the probable reason is that we don't
have any specific rule, so different people decide to do it
differently.

> > I think we shouldn't remove the extra line as part of the above change.
>
> I would take out the blank lines between our own #includes.
>

Okay, that would be better, but doing it half-heartedly as done in
patch might make it worse.  So, it is better to remove blank lines
between our own #includes in all cases.

-- 
With Regards,
Amit Kapila.
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