Re: Large C files

From: Peter Geoghegan <peter(at)2ndquadrant(dot)com>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Peter Eisentraut <peter_e(at)gmx(dot)net>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Jan Urbański <wulczer(at)wulczer(dot)org>
Subject: Re: Large C files
Date: 2011-09-07 01:14:18
Message-ID: CAEYLb_WfDK426cY35sG4JsaN+o9P0u4JiogbRCc_WrTL+EgKPg@mail.gmail.com
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On 7 September 2011 01:18, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> I am confused how moving a function from one C file to another could
> cause breakage?

I'm really concerned about silent breakage, however unlikely - that is
also Simon and Robert's concern, and rightly so. If it's possible in
principle to guard against a certain type of problem, we should do so.
While this is a mechanical process, it isn't quite that mechanical a
process - I would not expect this work to be strictly limited to
simply spreading some functions around different files. Certainly, if
there are any other factors at all that could disrupt things, a
problem that does not cause a compiler warning or error is vastly more
troublesome than one that does, and the most plausible such error is
if a symbol is somehow resolved differently when the function is
moved. I suppose that the simplest way that this could happen is
probably by somehow having a variable of the same name and type appear
twice, once as a static, the other time as a global.

IMHO, when manipulating code at this sort of macro scale, it's good to
be paranoid and exhaustive, particularly when it doesn't cost you
anything anyway. Unlike when writing or fixing a bit of code at a
time, which we're all used to, if the compiler doesn't tell you about
it, your chances of catching the problem before a bug manifests itself
are close to zero.

--
Peter Geoghegan       http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training and Services

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