Re: Significant oversight in that #include-removal script

Tom Lane wrote:
> I just noticed that optimizer/cost.h is not #include'd by plancat.c,
> which is not too cool because the former has the extern declaration
> for the constraint_exclusion global variable while the latter has
> the actual definition. I didn't run it down in the CVS history to
> make sure, but I imagine what happened is that your unnecessary-includes
> script diked it out because the file still compiled warning-free without
> that header, ie, there is no warning for "int foo;" not preceded by
> "extern int foo;". This isn't real good because it would allow a global
> variable to get out of sync with its declaration. Is there a way to
> prevent such problems in future?

The script certainly has no way to know it is missing an extern, and I
am not sure how I would even teach it that trick.

The example you saw was:

src/include/optimizer/cost.h:55:extern bool constraint_exclusion;
src/backend/optimizer/util/plancat.c:46:bool constraint_exclusion = false;

The only clean way I can think of to fix this would be to have all the
globals in a single C file that is included as part of postgres.h.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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