Re: [PATCH 1/6] meta/dpkg: Make 'do_unpack' more generic, prepare for pulling out

[Alexander Smirnov <asmirnov@ilbers.de>]

On 08/30/2017 10:03 PM, Henning Schild wrote:
> Issue:
> The unpacker in dpkg is not generic since it does not unpack to
> WORKDIR, so it can not be pulled into a more generic class to make it
> available for other users.
> 

As I already wrote to mail-list, WORKDIR and BUILDROOT are different 
folders, and there was the reason to do so.

In Yocto, WORKDIR is the place which keeps the following artifacts:

  - Source code tree
  - Patches, configs
  - Binaries
  - Yocto meta information (logs and build commands)

WORKDIR is usually something like: ./tmp/work/gcc-arch/package-name

Due to Yocto performs cross-compilation, it is able to keep source core 
out of cross filesystem. But this doesn't work for Isar, which uses 
'native' compilation in chroot. That's why BUILDROOT variable was 
introduced.

So in Isar, WORKDIR stays the same and keeps logs, build commands, 
patches and other stuff (for example configs and scripts for 
buildchroot). The BUILDROOT is the path to dedicated buildchroot where 
to unpack sources and build them.

If I build multiconfig for N targets with this patch, I will have N 
distributed locations with bitbake meta information for the same package.

If I cleanall buildchroot, I will lose all the bitbake meta information 
for current distro-arch.

So at the moment I don't see any benefit of this change.

Also it's not clear, what do you mean by 'not generic', this unpack 
implementation designed for building deb packages, and at the moment no 
other users are expected.

-- 
With best regards,
Alexander Smirnov

> Change:
> Make the unpacker generic by making it unpack to WORKDIR and keep the
> old semantic by overwriting this variable for the task do_unpack. Change
> the comment as well, it would be wrong outside this context.
> 
> Impact:
> This patch does not change the behaviour of Isar. It addresses the issue
> and prepares for another patch pulling the code to another class.
> 
> Signed-off-by: Henning Schild <henning.schild@siemens.com>
> ---
>   meta/classes/dpkg.bbclass | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/meta/classes/dpkg.bbclass b/meta/classes/dpkg.bbclass
> index 23d5e6c..81e21ce 100644
> --- a/meta/classes/dpkg.bbclass
> +++ b/meta/classes/dpkg.bbclass
> @@ -31,13 +31,15 @@ do_unpack[dirs] = "${BUILDROOT}"
>   do_unpack[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
>   S ?= "${BUILDROOT}"
>   
> -# Unpack package and put it into working directory in buildchroot
> +WORKDIR_task-unpack = "${BUILDROOT}"
> +
> +# Unpack package and put it into working directory
>   python do_unpack() {
>       src_uri = (d.getVar('SRC_URI', True) or "").split()
>       if len(src_uri) == 0:
>           return
>   
> -    rootdir = d.getVar('BUILDROOT', True)
> +    rootdir = d.getVar('WORKDIR', True)
>   
>       try:
>           fetcher = bb.fetch2.Fetch(src_uri, d)
>