[42296] trunk/dports/databases/db46/Portfile

[Ryan Schmidt]

On Nov 19, 2008, at 16:19, Trannie Carter wrote:

>>   One question and a little suggestion:
>>   Why a variant for this small utility?
>
> You mean as opposed to making it part of the default build?  I  
> agree that it is
> a relatively small utility to get its own variant.  The db44 port  
> enabled
> db_dump185 by default and mentioned it in the port description.  db46
> explicitly dropped that and I assumed there was a reason;  Probably  
> because not
> many people use db1.8 anymore :)  But I found an old bdb file I  
> needed access
> to, so I added a variant.
>
> I'll start posting to macports-dev when there's ambiguity.  I'm  
> still pretty
> new to ports best practices.

A variant should only be added if there is a really good reason why  
someone would want to not use it. :) For example, a good reason would  
be if the variant adds dependencies which are large or take a long  
time to build, or when there are conflicting options to choose from.  
Like php5 has mysql3, mysql4 and mysql5 variants; you must pick one  
of these if you want MySQL support, but you have to choose the one  
that matches your MySQL version. Also, e.g. mysql5 is a large  
download (27MiB), takes a lot of space after install (41MiB) and  
takes a long time to build (I forget how long at the moment).

You could ask whoever committed the removal of that program from db46  
initially why they did so.


>> Instead of testing whether the variant is set, you could write  
>> another
>> post-destroot block in the variant itself.
>
> Oh, I'm not familiar with that pattern.  I modeled that section  
> after the
> MacPorts Guide section 4.4.2 Variant Actions in a Phase.  Maybe  
> this new style
> is described in the trunk version of the guide.

The guide says [1]:

> If a variant requires options in addition to those provided by  
> keywords using -append and/or -delete, in other words, any actions  
> that would normally take place within a port installation phase, do  
> not try to do this within the variant declaration. Rather, modify  
> the behavior of any affected phases when the variant is invoked  
> using the variant_isset keyword.
>
> post-destroot {
>     xinstall -m 755 -d ${destroot}${prefix}/etc/
>     xinstall ${worksrcpath}/examples/foo.conf \
>         ${destroot}${prefix}/etc/
>
>     if {[variant_isset carbon]} {
>         delete ${destroot}${prefix}/bin/emacs
>         delete ${destroot}${prefix}/bin/emacs-${version}
>     }
> }


I have no idea why it says that. :) There's no reason I can think of  
not to do it within the variant declaration; in fact, I think it's  
preferable to keep all of the variant's dealings together in one  
place (the variant declaration).


[1] http://guide.macports.org/#development.variants.phase