[Buildroot] [PATCH] infra: Add a way to apply patches using git

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Dear J?r?me Pouiller,

On Wed,  2 Jul 2014 19:20:05 +0200, J?r?me Pouiller wrote:
> This option is mainly used for package developpers. When activated,
> Buildroot will automaticaly create a git repository for each package
> it extract. Initial version is tagged as `upstream'. Next, during
> patch step, git is used instead of patch. BTW, patches are easier
> to modify/fix/rebase/cherry-pick/upstream. Once satisfied with
> changes, developper may use
>     git format-patch -o $TOPDIR/package/$PKG upstream
> to save its patches to Buildroot.
> 
> Notice this option should be compatible with `guilt' (a clone of
> `quilt')
> 
> Notice you can also use this feature for a specific package using
>     make BR2_USE_GIT_TO_PATCH=y $PKG-dirclean $PKG-patch
> 
> Current known limitations:
>   - If a patch cannot be handled by `git am', we use `git apply`. In
>     this case, patch description is not reported in commit message.
>   - When patch is handled with `git apply`, subject used may not be
>     perfect (it is extracted from patch filename)
>   - `git format-patch' does not prefix patch files with name of package.
>   - If upstream was downloaded with git, we may also run
>     `git remote add $($(PKG)_SITE)' during git repository creation
> 
> Signed-off-by: J?r?me Pouiller <jezz@sysmic.org>

We discussed this proposal at the last Buildroot Developers meeting.
Even though we understand the idea and some of us found it potentially
interesting, we didn't really like the implementation, but nobody
really found a way of implementing something like this in a nice way.

One of the problem is that not all our patches are Git patches, which
you had to work-around in your patch in a way that isn't really nice.

Maybe Arnout and Yann (in Cc) remember more of the issues that we
discussed at the meeting regarding this proposal.

Thanks,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com