[Buildroot] [PATCH v2] support/download/git: Prioritize remote archive

[Yann E. MORIN <yann.morin.1998@free.fr>]

Benjamin, All,

On 2016-08-17 14:25 -0700, Benjamin Kamath spake thusly:
> From: Benjamin Kamath <bkamath@spaceflight.com>
> 
> Attempt to do a remote archive since it shortcuts us past a few steps when
> available. Additionally. if the git server has uploadArchive.allowUnreachable
> set to true, then this method can also work on arbitrary sha1s, offering a huge
> speed advantage over a full clone.
> 
> Signed-off-by: Benjamin Kamath <bkamath@spaceflight.com>
> ---
> Changes v1 -> v2:
>     - Skip remote archive for repositories with submodules (suggested by Yann)
> 
>  support/download/git | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/support/download/git b/support/download/git
> index 416cd1b..d060cbd 100755
> --- a/support/download/git
> +++ b/support/download/git
> @@ -36,6 +36,17 @@ _git() {
>      eval ${GIT} "${@}"
>  }
>  
> +# Try a remote archive, since it is as fast as a shallow clone and can give us
> +# an archive directly. Also, if uploadArchive.allowUnreachable is set to true
> +# on the remote, this will also work for arbitrary sha1s, and will offer a
> +# considerable speedup over a full clone. This will not work for submodules.
> +if [ ${recurse} -eq 0 ]; then
> +    printf "Doing remote archive\n"
> +    if _git archive --format=tar.gz --prefix=${basename}/ --remote=${repo} -o ${output} ${cset} 2>&1; then
> +        exit 0

I would have also done:

        else
            printf "Remote archive failed, falling back to cloning\n"

Like we do for the shallow clone.

Also, why do you redirect stderr? We don't do it in the clone commands.
We only do it to fetch the special references (gitHub PRs of Gerrit
changes) because it does not make sense to display an spurious message
when the reference is in fact not special.

Regards,
Yann E. MORIN.

> +    fi
> +fi
> +
>  # Try a shallow clone, since it is faster than a full clone - but that only
>  # works if the version is a ref (tag or branch). Before trying to do a shallow
>  # clone we check if ${cset} is in the list provided by git ls-remote. If not
> -- 
> 2.7.4
> 
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