Re: [gentoo-user] mysql is being pulled in again!

[Mick]

On 4 March 2010 20:07, Alan McKinnon <alan.mckinnon@×××××.com> wrote:
> On Thursday 04 March 2010 19:07:22 Mick wrote:
>> > There will be a reason why mysql is being pulled in, most likely a
>> > package that must have it.
>>
>> If a package must have it, wouldn't the USE flag mysql switch to + ?
>
> Your post seems to indicate a lack of understanding of how these things work.

Yep.  :-(

> Often-times things are not optional, that's what "must" means. USE is
> diametrically opposed to that as it has to imply a meaning of "may". If a
> package if hard-coded to use mysql, then it must have it, and putting it in
> USE in pointless.

I see.  I thought that (some relevant) USE flags reflected
dependencies at some level and that if a dependency changed then this
would reflect those USE flags which would now show up as active.  So I
thought that the mysql USE flag would change from - to +.

> There's no rule about this. If mysql is a hard dep, then that's the way it is.
>
>> > If a user wants postgres, he should install and run postgres. How would
>> > this affect the presence or absence of mysql?
>>
>> Well, I am assuming that if postgres can do what mysql does, then it
>> could work in its place.  Like if syslog-ng will do what metalog does,
>> then the virtual/log-thingie will not insist in pulling in metalog.
>> Anyway, the postgres is just an example of asking why are we locking
>> down the choice of a database to a particular package/provider.
>
> Again, you appear to fail to understand. metalog supports a variety of
> database backends. Not all apps are like this, some are hard-coded. If you
> want to use an app like this, you have no choice but to install mysql.
>
> If you don't like this, then your choices number two:
>
> 1. Tough, get over it;
> 2. Use a different app

No I think you fail to understand what I fail to understand!  Ha, ha!  :-))

I was not talking about what db a syslog app will use as a back end.
I was trying to understand why a virtual package like virtual/mysql is
pulling in dev-db/mysql and I used the syslog virtual/real
relationship as an analogy.  Anyway, I now know two things:

a) qt-sql pulled in mysql

b) when the wife shouts at me to get going with chores, I do not start
an emerge without first checking the contents of it!  :-))

Thanks again for your replies.
-- 
Regards,
Mick