Re: [PATCH v4 1/1] meta: added do_transform_template task as templating system and switch

[Claudius Heine <claudius.heine.ext@siemens.com>]

Hi Jan,

On Sun, 2019-03-24 at 19:28 +0100, Jan Kiszka wrote:
> On 14.02.19 12:28, [ext] claudius.heine.ext@siemens.com wrote:
> > From: Claudius Heine <ch@denx.de>
> > 
> > The new introduced variables are TEMPLATE_FILES and TEMPLATE_VARS.
> > TEMPLATE_FILES is a list of files that should be processed in the
> > `do_transform_template` task and TEMPLATE_VARS is a list of bitbake
> > variable names that should be substituted in the template file.
> > 
> 
> Bad news: This patch introduced a regression into the release (sorry,
> didn't
> manage to test earlier). It destroys the reuse of self-built
> identical packages
> for different targets. Namely, jailhouse-images now tries to build
> the shared
> (per arch) kernel multiple times, and that fails miserably because
> there is a
> common folder for all of them. The issue disappears when removing the
> do_transform_template task from the chain.

Hmm, have you looked at the resulting 'TEMPLATE_VARS' variable? All
variables in there need to be the same in order for it to have the same
stamp. If that is not the case then maybe overwriting it instead of
appending it might work.

These are the defaults set in 'template.bbclass':

    TEMPLATE_VARS ?= "PN PV DESCRIPTION HOMEPAGE MAINTAINER KERNEL_NAME
                      MACHINE DISTRO_ARCH"

If I understand you correctly then your recipe should not be dependant
on the MACHINE? So either remove MACHINE 'TEMPLATE_VARS_remove =
"MACHINE"' or just set a 'TEMPLATE_VARS' that you really need in your
template files.

Cheers,
Claudius

> 
> Digging deeper, the reason is that do_transform_template is not
> shared but run
> multiple times (even if nothing has to be done), forcing all
> succeeding tasks
> into private mode as well. I suspect that's because bitbake cannot
> assess if the
> output of the task python function is identical. I guess we need to
> help bitbake
> here. Any idea how? Own stamping logic?
> 
> Jan