[Buildroot] [RFC PATCH 3/3] download/git: unshallow when fetching all refs

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

Thanks a lot Ricardo for all this work on the download issues, much
appreciated. One question on this specific commit.

On Thu, 12 Apr 2018 06:28:55 -0300, Ricardo Martincoski wrote:
> With any version of git, after the git cache was once populated using a
> shallow fetch, a full fetch succeeds but doesn't download the commits
> behind the reference that was fetched with --depth 1. In this case the
> download fails like this:
>  Fetching all references
>  Could not fetch special ref 'sha1'; assuming it is not special.
>  fatal: reference is not a tree: sha1
> 
> One scenario in buildroot development that would trigger this sequence
> is for example when a package is bumped on master branch, some users
> create the git cache at this time, then the bump is reverted.
> 
> Another scenario is when giving maintenance to a product version that
> uses one version of buildroot using the same build farm that uses a
> newer version of buildroot.

In the light of this, wouldn't it be simpler to stop doing shallow
clones at all ? A shallow clone did make a lot of sense back when we
didn't cache the Git repositories. But now that we are caching the
results, does it make sense to keep the complexity of the code to use
shallow clones ?

Note that this is really an open question, there are possibly some
convincing argument for us to keep a shallow clone strategy.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com