[libvirt] [PATCH] Allow bootstrap to build gnulib from local git source if $GNULIB_SRCDIR is non-empty.

[Prerna Saxena]

Hi Eric,

On 05/10/2011 01:16 AM, Eric Blake wrote:
> On 05/09/2011 02:25 AM, Prerna Saxena wrote:
>> 'bootstrap' script clones the .gnulib submodule from upstream git
>> sources only (provided in .gitmodules), irrespective of whether
>> $GNULIB_SRCDIR is provided.
>
> Which is what we want.  A local gnulib checkout is not the same as
> upstream gnulib, and we want to ensure that no one commits to upstream
> libvirt.git unless the .gnulib submodule also points to upstream
> gnulib.git.  Otherwise, we risk the scenario that something that works
> for you with your local gnulib commit won't work for anyone else because
> your gnulib commit is not public.
>

Thank you for the detailed explanation.
The need for this patch arose because I was trying to build libvirt in a 
restrictive environment without outbound network access, and wanted to 
force libvirt to use the gnulib sources provided locally.
However,libvirt would necessarily clone from the reference provided in 
$GNULIB_SRCDIR/.git/config, which happened to be 
git://git.sv.gnu.org/gnulib.git
This patch was meant to be a workaround to prevent autogen.sh from 
failing at clone of gnulib.
Your note has been pretty helpful in suggesting the --no-git workaround. 
I was not aware of this option. I am trying to build it and see if it 
works for me.

>> This patch allows gnulib git sources provided by $GNULIB_SRCDIR to be
>> used for adding the gnulib submodule.
>
> NAK.
>
> GNULIB_SRCDIR is used to prime the pump - if you have a local checkout,
> then you don't need quite as much disk space or network usage to create
> your clone (your clone in .gnulib will implicitly point to your prior
> gnulib checkout as its reference).  But you _still_ need .gnulib to be
> independent of your local reference repository, since it is possible
> that libvirt intentionally lags upstream gnulib, or that libvirt wants
> to use a newer upstream gnulib than what you have in your local
> reference repository at the moment.
>
> Furthermore, you can use:
>
> ./bootstrap --no-git --gnulib-srcdir=/path/to/local
>
> as a means of checking out the exact version of gnulib that you desire
> without referencing upstream gnulib.git.
>
> Finally, this patch would have to go to upstream gnulib.git, since
> libvirt's copy of this file is a direct clone of upstream gnulib's
> bootstrap.  Unless you can get this accepted upstream, then libvirt
> should not behave differently than  any other project that uses gnulib's
> bootstrap script.
>

Ah yes! This is an additional complexity which I had hitherto not 
factored in  :)

-- 
Prerna Saxena

Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India