Re: [gentoo-dev] [git migration] The problem of ChangeLog generation

[Nirbheek Chauhan <nirbheek@gentoo.org>]

On Tue, Apr 6, 2010 at 12:11 PM, Fabian Groffen <grobian@gentoo.org> wrote:
> On 06-04-2010 07:43:02 +0530, Nirbheek Chauhan wrote:
>> * It makes zero sense to manually manage ChangeLogs in git[1]
>>   - Irritating conflicts while merging branches or remote master
>>     + Similar argument for having only distfile manifests; but I digress...
>>   - Duplication of effort and information
>>   - Saves space for local checkouts
>
> This seems to assume
> a) that we will do branches, and
> b) that those branches somehow are official and in use
>

No. Conflicts can arise (and I have seen them arise) trivially if you
make changes and try to do a pull --rebase; which is then not
fast-forward, and you're left with an ugly mess of conflicts on your
hands. Say you're moving stuff from an overlay using git format-patch;
how do you handle the conflicts it will generate to ChangeLogs and
Manifests?

Also, this is not the only reason to not use ChangeLogs.

Trivial example purely for demonstrative purposes:

Without ChangeLog:
make change1; commit; test; realise it needs change2; commit; test;
rebase commits; push
With ChangeLog:
make change1; write ChangeLog; commit; test; realise it needs change2;
reset --hard ChangeLog HEAD^; rewrite ChangeLog; commit; test; rebase
commits; push

Now which is easier? Don't forget that the major reason for moving to
git was the ability to make several local commits and pushing them in
an atomic way; so you are bound to make mistakes and want to rebase.

> If you really have lots of changes, you will find that many commits on
> the other side will cause you conflicts, so the ChangeLog is just a very
> small part of it.

I bump an ebuild; arch team member marks older version stable. Two
completely orthogonal changes that conflict now. With ChangeLogs,
*every* *single* change you make conflicts. You do a rebase; and it
conflicts! It's just stupid.

Extreme example: profiles/ChangeLog

> Conclusion, if you can, try hard to keep your changes
> minimal, and preferably zero compared to the origin, gentoo-x86.
>

With the inevitable increased activity on the gentoo-x86 tree, this
will become more and more difficult.

-- 
~Nirbheek Chauhan

Gentoo GNOME+Mozilla Team