[packagers] The demise of the repotag

[Kjeldgaard Morten]

Rex wrote:

>
> No, I can't just trust you, I need more.  I need details on how to  
> reproduce the problem so that I can fix it.
>

WTF? You really don't get it, do you? There is nothing "wrong" with  
your fftw package per se. You can only "fix it" by renaming it to  
"fftw3". Just go in the .spec file and add that little "3" in the  
Name: field. Recompile. Then, you will be compatible with the rest of  
the world.

> fftw2 is still packaged.  Are you saying that's broken somehow too?

Probably not. I have installed package fftw which is FFTW2.  I do  
*not* want version 3. If I did, I would simply install fftw3 (from  
rpmforge).

The following is from the FFTW FAQ:
> Question 3.1. Why not support the FFTW 2 interface in FFTW 3?
>
> FFTW 3 has semantics incompatible with earlier versions: its plans  
> can only be used for a given stride, multiplicity, and other  
> characteristics of the input and output arrays; these stronger  
> semantics are necessary for performance reasons. Thus, it is  
> impossible to efficiently emulate the older interface (whose plans  
> can be used for any transform of the same size). We believe that it  
> should be possible to upgrade most programs without any difficulty,  
> however.
... but lots of software still depends on FFTW2. Programmers are lazy.

So the "problem" is that your kde-redhat repo upgrades my  
fftw-2.1.5-4.2.el4.rf  package to version 3.

Originally, when Dag started to package fftw, he did not/could not  
know that sometime in the future, there would be a new version of  
fftw that would not be compatible with version 2. So he, and everyone  
else, packaged the suite under the name "fftw". Then, when version 3  
came, Dag (I am guessing) read the FAQ and saw that the new version  
was incompatible with the old one. So, the new package was very  
logically named "fftw3". Very simple: FFTW2 is "fftw" and FFTW3 is  
"fftw3". Check the Debian and Fink repos if you wish, it's the same  
story.

So, why should I and the whole of the rest of the world suddenly want  
to uninstall fftw and install fftw2 just because you decided to give  
it a new name?

-- Morten


PS: Probably not many people are interested in the fast fourier  
transform package, but I find it is worth having the discussion in  
this forum because it is pretty illustrative of the problems that  
arise in the "multi-repo" approach. Unless extreme discipline is  
exercised by the different repos, it quickly turns into "dependency  
hell". This is just _one_ package we've been discussing. There are  
thousands of others.