[Buildroot] [PATCH v2 2/2] pkg-generic: Cleanup some redundant checks

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

Norbert, All,

On 2019-03-17 22:20 +0100, Norbert Lange spake thusly:
> With the last change, packages will depend
> only on host-{xz,lzip} if the source archives
> have filenames requesting the corresponding compressor.
> 
> This allows using a single guard.

This commit log is an improvement agaisnt the previous one, yet I still
had to think a bit too hard to understand the reason that works.

And I think there is an issue with that. Not today, but that opens up a
case where we can introduce a subtil bug in the future.

If, say, xz changes its distribution archive from .bz2 to .lz, iand lzip
changes theirs from .gz to .xz, then we'd introduce a circular
dependency at the make level, and make silently and arbitrarily drops
one of the dependencies.

However, now that I think about it, that is of not big consequence: in
either case, the build woulld break on the first one we try to extract,
and we would notice quite early and quite easily.

Still, I'd like we think a bit harder about those special cases.

Regards,
Yann E. MORIN.

> Signed-off-by: Norbert Lange <nolange79@gmail.com>
> ---
>  package/pkg-generic.mk | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/package/pkg-generic.mk b/package/pkg-generic.mk
> index 89da43d5e5..11f16cab18 100644
> --- a/package/pkg-generic.mk
> +++ b/package/pkg-generic.mk
> @@ -604,18 +604,15 @@ endif
>  
>  ifeq ($$(filter host-tar host-skeleton host-fakedate,$(1)),)
>  $(2)_EXTRACT_DEPENDENCIES += $$(BR2_TAR_HOST_DEPENDENCY)
> -endif
>  
> -ifeq ($$(filter host-tar host-skeleton host-xz host-lzip host-fakedate,$(1)),)
>  ifneq ($$(filter .xz .lzma,$$(suffix $$($(2)_SOURCE))),)
>  $(2)_EXTRACT_DEPENDENCIES += $$(BR2_XZCAT_HOST_DEPENDENCY)
>  endif
> -endif
>  
> -ifeq ($$(filter host-tar host-skeleton host-xz host-lzip host-fakedate,$(1)),)
>  ifeq ($$(suffix $$($(2)_SOURCE)),.lz)
>  $(2)_EXTRACT_DEPENDENCIES += $$(BR2_LZIP_HOST_DEPENDENCY)
>  endif
> +
>  endif
>  
>  ifeq ($$(BR2_CCACHE),y)
> -- 
> 2.20.1
> 
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