[Buildroot] Suggestion to "support/scripts/apply-patches.sh: do not apply patches with renames"

[Yann E. MORIN]

Peter, Ryota, All,

On 2021-05-15 08:44 +0200, Peter Korsgaard spake thusly:
> >>>>> "Ryota" == Ryota Kinukawa <pojiro.jp at gmail.com> writes:
>  > Hi. Thank you for your great work, Buildroot team.
>  > I'm writing this email for suggestions to support/scripts/apply-patches.sh.
> 
>  > Recently, I was working with buildroot to apply patches-4.14.164-rt73.
>  > It included a patch((patches-4.14.164-rt73/0462-..)) which renames a file.
>  > This caused the build to terminate with an error.
[--SNIP--]
> The problem with such an option is that it describes a property of the
> build host, not of the Buildroot configuration - And we still wouldn't
> be able to use rename patches as long as that option was supported.
> 
> So we want apply-patches.sh to work the same for everyone.
> 
> But we're now 4 years later, so perhaps it is time to unconditionally
> drop support for GNU patch < 2.7?
> 
> GNU patch 2.7 was released in September 2012, so 8.5 years ago:
> 
> https://savannah.gnu.org/forum/forum.php?forum_id=7361
> 
> Thomas, Yann - Any ideas how common such old patch version are nowadays?

One of the oldest supported distro that was rel;eased before patch 2.7,
is RHEL 6. It has entered Extended Support in late 2020, and is expected
to be supported until mid 2024. However, consdering this is an old
distro, Iand that there were CVes on patch < 2.7 I'd expect that RHEL 6
now packages a newer patch that is >= 2.7.

People that do not update their systems, and are stuck on so old a host
distro, will probably not update their Buildroot version either...

On the Ubuntu side (as another data point), the odest LTS is Trusty,
14.04, and it has patch 2.7.1.

As for Debian, the oldest still supported is Jessie, with Extended LTS
until mid 2022, and it was released in 2015, so presumably has patch >=
2.7 too.

So, I would be OK for requiring patch >= 2.7.

So, lets do it that way;

 1. add a check in support/dependencies/dependencies.sh that patch >=
    2.7 (just after/before the check for --no-backup-if-mismatch)

 2. drop the test for renames in support/scripts/apply-patches.sh

Ryota, would you care to work on that and send the patches to the list,
please?

Regards,
Yann E. MORIN.

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