Re: [gentoo-dev] portage question

["Christian Skarby" <christian@skarby.no>]

> On Wed, 2 Oct 2002 13:53:39 +0200 (CEST)
> "Christian Skarby" <christian@skarby.no> wrote:
>
>> I kind of like the idea of this feature, but AFAIK are diffs most
>> usefull when there are little difference from the source-files we
>> already have. I.e. as soon as all the code is changed a diff-file will
>> include both the old and the new source. If we implement this feature
>> I think it would be nice to put some logic into it so that it can
>> (f.ex. by looking at file-sizes) decide if one should download a patch
>> or two or rather download the full source.
>
> the whole point of a diff/patch file is to make only changes made to the
> source .. not carry the original ..
>
> Henti Smith

:) I think I'll have to be a bit more spesific on this

If we have a source-1.0 that reads
/*
 This is a lovely comment
*/

and then a source-1.1 that reads
/*
 This comment make more sense
*/

a diff would look something like
/*
- This is a lovely comment
+ This comment make more sense
*/

As we see the diff is larger than both the sources, and this will happen
as soon as the all the source is fully replaced. This is actually a worst
case scenario and hence not a good example, nevertheless I believe that
fetching source-1.0.tar.gz and patch-1.1.tar.gz often will result in
downloading more than just source-1.1.tar.gz, thus it will not be cost
effective to get the patch unless one already have the sources that the
patch applies to. Therefor I believe that if we should implement this into
portage it would be nice to have some checks looking at what relevant
source-files we already have, how large the patches are and how large the
full source download is. Then it should be quite easy to consider what
will be the least time consuming download.

Taking in consideration that many (most/all?) gentoo-users keep their
systems up to date at all times with emerge -u world it probably would be
a great ideá just with patches, but I think that new installs and install
of packages with huge rewrites will benefit from having clean full source
downloads. Thus I suggest these checks.

Please arrest me if I am wrong ..

All the best,
Christian