[Buildroot] [PATCH 06/16 v3] core/legal-info: ensure legal-info works in off-line mode

[Luca Ceresoli <luca@lucaceresoli.net>]

Hi Yann,

Yann E. MORIN wrote:
> Almost all packages which are saved for legal-info have their source
> archives downloaded as part of 'make source', which makes an off-line
> build completely possible [0].
>
> However, for the pre-configured external toolchains, the source tarball
> is different, as the main tarball is a binary package. And that source
> tarball is only downloaded during the legal-info phase, which makes it
> inconvenient for full off-line builds.
>
> We fix that by adding a new rule, $(1)-legal-source which only
> $(1)-all-source depends on, so that we only download it for a top-level
> 'make source', not as part of the standard download mechanism (i.e. only
> what is really needed to build).
>
> This way, we can do a complete [0] off-line build and are still able to
> generate legal-info, while at the same time we do not incur any download
> overhead during a simple build.
>
> Also, we previously downloaded the _ACTUAL_SOURCE_TARBALL when it was
> not empty. However, since _ACTUAL_SOURCE_TARBALL defaults to the value
> of _SOURCE, it can not be empty when _SOURCE is not. Thus, we'd get a
> spurious report of a missing hash for the tarball, since it was not in
> a standard package rule (configure, build, install..) and thus would
> miss the PKG and PKGDIR variables to find the .hash file.
>
> We fix that in this commit as well, by:
>
>    - setting PKG and PKGDIR just for the -legal-source rule;
>
>    - only downloading _ACTUAL_SOURCE_TARBALL if it is not empty *and* not
>      the same as _SOURCE (to avoid a second report about the hash).
>
> [0] Save for nodejs which invarriably wants to download stuff at build
> time. Sigh... :-( Fixing that is work for another time...

Thanks for the detailed comment!
I didn't even find any typo... :) but I have a note below.

> @@ -771,6 +775,20 @@ endif
>   endif
>   endif
>
> +# Download actual sources if they differ from the extracted sources
> +# (e.g. for external toolchains)
> +#
> +# We need to provide PKG and PKGDIR, because there's no .stamp file for
> +# the legal-info step.
> +$(1)-legal-source:	PKG=$(2)
> +$(1)-legal-source:	PKGDIR=$(pkgdir)
> +$(1)-legal-source:
> +ifneq ($$($(2)_ACTUAL_SOURCE_TARBALL),)
> +ifneq ($$($(2)_ACTUAL_SOURCE_TARBALL),$$($(2)_SOURCE))
> +	$$(call DOWNLOAD,$$($(2)_ACTUAL_SOURCE_SITE)/$$($(2)_ACTUAL_SOURCE_TARBALL))
> +endif # actual sources != sources
> +endif # actual sources != ""

This created a side effect that is harmless, but a bit unpleasant.

Before this patch, running 'make source' with all sources already
fetched did not produce any output. Now, when using a package that 
defines _ACTUAL_SOURCE_SITE, it does:

$ make source
arm-2014.05-29-arm-none-linux-gnueabi.src.tar.bz2: OK (sha256: [...])
$

This is caused by not having a stamp file for the actual source
tarball. I suppose we should create a .stamp_actual_downloaded.

For the rest the patch looks good and it works.

-- 
Luca