[Buildroot] Why not perform a shallow clone?

[Patrick Doyle]

On Wed, Feb 24, 2016 at 2:50 PM, Patrick Doyle <wpdster at gmail.com> wrote:
> On Wed, Feb 24, 2016 at 2:41 PM, Samuel Martin <s.martin49 at gmail.com> wrote:
>> Hi,
>>
>> On Wed, Feb 24, 2016 at 8:30 PM, Patrick Doyle <wpdster at gmail.com> wrote:
>>> So I'm sitting here watching my buildroot make do a complete clone of
>>> the Linux kernel, where I have told it that I want a specific sha1
>>> commit and I started wondering...
>>>
>>> Why not do a shallow clone?
>> It tries, but cannot (see
>> https://git.buildroot.org/buildroot/tree/support/download/git#n34)
>>
> Oh bummer...
>
> I wonder why git-clone -b doesn't accept a sha1sum.  Oh well.
Oh, here's the answer (from
http://thread.gmane.org/gmane.comp.version-control.git/115811):

> Is there a way to fetch based on SHA id's instead of named references?

No, out of security concerns;  imagine you included some proprietary
source code by mistake, and undo the damage by forcing a push with a
branch that does not have the incriminating code.  Usually you do not
control the garbage-collection on the server, yet you still do not want
other people to fetch "by SHA-1".

Oh well.

>
>
> So how do you folks handle pinning a revision of, for example, the
> kernel?  I naively assumed that I would specify
> BR2_LINUX_KERNEL_CUSTOM_REPO_URL and
> BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION, which appears to do what I want,
> but it seems wasteful to have to clone the whole Linux repo just to
> get that one clone.
>
> I suppose I could tell menuconfig that the (Atmel) kernel I am cloning
> is available on github somehow and have the magic "fetch a sha1sum
> from github" work.  I'll go think about that for a bit.

No, that doesn't seem to work either.  linux.mk doesn't use $(call
github).  Oh well.

I suppose I could add support for that... does that seem useful to
folks other than I?

--wpd