Re: Extensions, this time with a patch

Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> Hmm, the first thought that comes to mind is that the GucContext param
> to ParseConfigFile is unused and can be removed. This is probably an
> oversight from when include files were introduced in 2006.

Thanks for caring about that part.

> I don't like the fact that this code handles custom_variable_classes
> internally. I think this would be exposed to the parsing of extension
> control files, which is obviously wrong.

Well, in fact, not that much. The extension code has a special error
case when dealing with custom variables if the class hasn't been already
parsed, and what ParseConfigFile() is doing is pushing the
custom_variable_classes setting in front of the list.

guc-file.l says:
/*
* This variable must be processed first as it controls
* the validity of other variables; so it goes at the head
* of the result list. If we already found a value for it,
* replace with this one.
*/

extension.c says:
ereport(ERROR,
(errmsg("Unsupported parameter '%s' in file: %s",
tok1, filename),
errhint("Be sure to have 'custom_variable_classes' set "
"in a line before any custom variable.")));

So if we don't change the code in ParseConfigFile() that will push
custom_variable_classes in front of the list, all I have to change in
the extension.c file is the error message.

I fail to see a future usage of custom_variable_classes where it
wouldn't help to have that in the list before any user setting that
depends on it.

Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support