[Buildroot] [PATCH 1/4] core/pkg-infra: introduce download features concept

[Vincent Fazio]

Arnout,

On 1/20/20 3:07 PM, Arnout Vandecappelle wrote:
>
> On 20/01/2020 21:38, Vincent Fazio wrote:
>> Arnout, Yann, et al
>>
>> On 1/20/20 2:56 AM, Arnout Vandecappelle wrote:
>>> On 17/01/2020 17:44, Yann E. MORIN wrote:
>>>
>>> [snip]
>>>> At some point in the past, Arnout expressed some concern about adding yet
>>>> more variables,
>>>    That was more about internal variables, not user-facing variables. And also
>>> about variables that are actually assigned to. Each variable that is set in
>>> inner-generic-package gets multiplied a thousandfold and this puts pressure on
>>> the internal tables in make.
>>>
>>>> and this feature thingy would be the opportunity to
>>>> coalesce many variables into a single one (or rather, avoiud adding new
>>>> variables).
>>>    Iff there are several users of it. So, as I said, it's a good idea if we get 4
>>> features.
>> So it sounds like this is too much infrastructure change until we have 4
>> definitive use-cases.
>>
>> At this time, we only have one (git submodules). My intent with this series was
>> to add the foundation for supporting git-lfs (which would be the second
>> use-case) and others.
>>
>> Based on the conversation, it seems like until we have a hard requirement from
>> other backends (hg and svn as previously mentioned), this series is DOA and that
>> git-lfs support should be added via some <pkg>_GIT_LFS define as was originally
>> submitted here: http://lists.busybox.net/pipermail/buildroot/2018-April/219716.html
>>
>> My main goal here is to add git-lfs support, regardless of how that needs to
>> happen. If resubmitting the original patch gets that done, that's what I'll do.
>   Yes, I think the original patch should be fine. Just also add git-lfs to
> DL_TOOLS_DEPENDENCIES, and test if it still works correctly if you don't have
> git-lfs installed on your host.

I have a series staged here with most of that support: 
https://gitlab.com/vfazio/buildroot/merge_requests/4/commits

I opted to create a host package for git-lfs in the case the host was 
missing it.. but can drop that if we'd rather enforce the host to have 
it pre-installed.

I was a bit confused on the difference between DL_TOOLS_DEPENDENCIES and 
<PKG>_DOWNLOAD_DEPENDENCIES and opted for the latter, but can change that.

>   Ideally there should also be a package in-tree that uses it, but I can imagine
> that it will be hard to find one... Failing that, a test case would be nice -
> but again, that may be difficult to implement without relying on some
> server-side support for it.
As you mention, a test case will be difficult without a server 
implementing the protocol and I expect most packages that need this 
functionality will be external tree packages (we need it for vendor 
supplied binaries for which sources are not available).
>   Regards,
>   Arnout
>
>
>> Please let me know your thoughts.
>>
>>>    Regards,
>>>    Arnout

-- 
Vincent Fazio
Embedded Software Engineer - Linux
Extreme Engineering Solutions, Inc
http://www.xes-inc.com