[OE-core] [PATCH] base.bbclass: fix do_unpack[cleandirs] varflag handling

[Enrico Joerns]

Hey,

any comments on that? Not using this patch currently disturbs our 
companies Yocto kernel workflow. Thus I wonder if no one else have had 
issues when building kernels from fully custom 'defconfig' files, too.

Regards, Enrico

On 01/21/2018 12:44 AM, Enrico Jorns wrote:
> As introduced by a56fb90dc3805494eeaf04c60538425e8d52efc5 ('base.bbclass
> wipe ${S} before unpacking source') the base.bbclass uses a python
> anonymous function to set the 'do_unpack' varflag 'cleandirs' to either
> '${S}' or '${S}/patches' depending on equality of '${S}' and '${WORKDIR}'.
> 
> Not that this only differs from the way almost all other recipes set or
> modify a tasks 'cleandirs' flag, it also has a significant impact on the
> kernel.bbclass (and possibly further ones) and causes incorrect
> behavior for rebuilds triggered by source modification, e.g. by a change
> of the defconfig file for a kernel build.
> 
> The kernel.bbclass tries to extend do_unpack[cleandirs]:
> 
> | do_unpack[cleandirs] += " ${S} ${STAGING_KERNEL_DIR} ${B} ${STAGING_KERNEL_BUILDDIR}"
> 
> As python anonymous functions are evaluated at the very end of recipe
> parsing, the d.setVarFlag('do_unpack', 'cleandirs', '${S}') statement in
> base.bbclass will overwrite every modification to cleandirs that is done
> as shown for the kernel class above.
> 
> As a result of this, a change to a kernels 'defconfig' will lead to an
> updated defconfig file in ${WORKDIR}, but as ${B} never gets cleaned and
> ${B}/.config still exists, it will not be copied to ${B}/.config and
> thus not find its way in the build kernel.
> 
> This is a severe issue for the kernel development and build process!
> 
> This patch changes setting of the cleandirs varflag in base.bbclass to
> a simple variable assignment as almost all other recipes do it. This now
> again allows overwriting or appending the varflag with common methods
> such as done in kernel.bbclass.
> 
> This issue affects morty, pyro, rocko and master.
> 
> Signed-off-by: Enrico Jorns <ejo at pengutronix.de>
> ---
>   meta/classes/base.bbclass | 8 ++------
>   1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/meta/classes/base.bbclass b/meta/classes/base.bbclass
> index 912e81e002..2949b074d8 100644
> --- a/meta/classes/base.bbclass
> +++ b/meta/classes/base.bbclass
> @@ -152,12 +152,8 @@ python base_do_fetch() {
>   addtask unpack after do_fetch
>   do_unpack[dirs] = "${WORKDIR}"
>   
> -python () {
> -    if d.getVar('S') != d.getVar('WORKDIR'):
> -        d.setVarFlag('do_unpack', 'cleandirs', '${S}')
> -    else:
> -        d.setVarFlag('do_unpack', 'cleandirs', os.path.join('${S}', 'patches'))
> -}
> +do_unpack[cleandirs] = "${@d.getVar('S') if d.getVar('S') != d.getVar('WORKDIR') else os.path.join('${S}', 'patches')}"
> +
>   python base_do_unpack() {
>       src_uri = (d.getVar('SRC_URI') or "").split()
>       if len(src_uri) == 0:
> 

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