RE: [OE-core] [PATCH] bitbake.conf: Add COMMON_LICENSE_DIR to BB_HASHEXCLUDE_COMMON

[Peter Kjellerstedt <peter.kjellerstedt@axis.com>]

> -----Original Message-----
> From: Richard Purdie <richard.purdie@linuxfoundation.org>
> Sent: den 13 februari 2022 22:44
> To: Peter Kjellerstedt <peter.kjellerstedt@axis.com>; openembedded-core@lists.openembedded.org
> Subject: Re: [OE-core] [PATCH] bitbake.conf: Add COMMON_LICENSE_DIR to BB_HASHEXCLUDE_COMMON
> 
> On Sun, 2022-02-13 at 21:34 +0100, Peter Kjellerstedt wrote:
> > Differences in COMMON_LICENSE_DIR should not affect the task hashes.
> >
> > Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
> > ---
> >  meta/conf/bitbake.conf | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
> > index fba99e8f0c..47c8cb39f9 100644
> > --- a/meta/conf/bitbake.conf
> > +++ b/meta/conf/bitbake.conf
> > @@ -922,7 +922,7 @@ BB_HASHEXCLUDE_COMMON ?= "TMPDIR FILE PATH PWD BB_TASKHASH BBPATH BBSERVER DL_DI
> >      BB_WORKERCONTEXT BB_LIMITEDDEPS BB_UNIHASH extend_recipe_sysroot DEPLOY_DIR \
> >      SSTATE_HASHEQUIV_METHOD SSTATE_HASHEQUIV_REPORT_TASKDATA \
> >      SSTATE_HASHEQUIV_OWNER CCACHE_TOP_DIR BB_HASHSERVE GIT_CEILING_DIRECTORIES \
> > -    OMP_NUM_THREADS BB_CURRENTTASK"
> > +    OMP_NUM_THREADS BB_CURRENTTASK COMMON_LICENSE_DIR"
> >  BB_HASHBASE_WHITELIST ?= "${BB_HASHEXCLUDE_COMMON} PSEUDO_IGNORE_PATHS BUILDHISTORY_DIR \
> >      SSTATE_DIR SOURCE_DATE_EPOCH"
> >  BB_HASHCONFIG_WHITELIST ?= "${BB_HASHEXCLUDE_COMMON} DATE TIME SSH_AGENT_PID \
> 
> I think this has been discussed before and I'm very uneasy at the idea. Some
> users would expect that if they add "their" version of a license in a layer with
> higher priority, they'd expect the hashes to change.

If the value was a relative path I could buy that, but not for an 
absolute path.

> Where is this causing an issue?

Due to the huge number of licenses in meta/files/common-licenses after 
all SPDX licenses were added, we cannot use that directory anymore as 
it triples the recipe parsing time for us (since we define 
INCOMPATIBLE LICENSE as AVAILABLE_LICENSES minus COMPATIBLE_LICENSES, 
and the license code doesn't really handle having many hundreds of 
licenses in INCOMPATIBLE LICENSE). Thus as a workaround I have had to 
create a common-licenses directory in one of our layers which only has 
symbolic links to the licenses in meta that we need. Then we set:

COMMON_LICENSE_DIR := "${LAYERDIR}/files/common-licenses"

in that layer's layer.conf, but since ${LAYERDIR} varies from build host 
to build host, our whole global sstate was now only useable on the build 
servers and not for local developer builds.

> 
> The whole idea of the "common" licenses probably needs revisiting anyway
> too :/
> 
> Cheers,
> 
> Richard

//Peter