Re: Large C files

On Tue, Sep 6, 2011 at 9:14 PM, Peter Geoghegan <peter@2ndquadrant.com> wrote:
> On 7 September 2011 01:18, Bruce Momjian <bruce@momjian.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.

I was less concerned about the breakage that might be caused by
variables acquiring unintended referents - which should be unlikely
anyway given reasonable variable naming conventions - and more
concerned that the associated refactoring would break recovery.  We
have no recovery regression tests; that's not a good thing.

-- 
Robert Haas
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