Re: [PATCH 1/3] make deb_add_changelog idempotent

["Moessbauer, Felix" <felix.moessbauer@siemens.com>]

On Mon, 2023-01-09 at 10:19 +0100, Henning Schild wrote:
> Am Mon,  9 Jan 2023 05:14:26 +0000
> schrieb Felix Moessbauer <felix.moessbauer@siemens.com>:
> 
> > Previously, the deb_add_changelog function considered an
> > auto-generated changelog as a base to add changes on top. This
> > behavior is not idempontent on subsequent invocations of the
> > function
> > (e.g. on partial rebuilds). This lead to both reproducability
> > issues,
> > as well as unclean changelog files having multiple "generated by
> > ISAR" entries.
> 
> Can you provide an example of that? Like how the wrong changelog
> would
> look like and why it would be wrong.

Consider this changelog file:

[...]

reprotest (1.0) UNRELEASED; urgency=low

  * generated by Isar

 -- Unknown maintainer <unknown@example.com>  Thu, 01 Jan 1970 00:00:42
+0000

reprotest (1.0) UNRELEASED; urgency=low

  * generated by Isar

 -- Unknown maintainer <unknown@example.com>  Thu, 01 Jan 1970 00:00:00
+0000

> 
> partial rebuilds (especially when code was modified inbetween) are
> hard
> to argue in the context of reproducible builds.
> 
> > This patch changes this implementation in a way to always create a
> > (possibly empty) orig changelog on the first invocation. On
> > subequent
> > invocations, the orig changelog is only considered as provided by
> > the
> > user, if it is not empty.
> > 
> > Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
> > ---
> >  meta/classes/debianize.bbclass | 14 +++++++++-----
> >  1 file changed, 9 insertions(+), 5 deletions(-)
> > 
> > diff --git a/meta/classes/debianize.bbclass
> > b/meta/classes/debianize.bbclass index d125256..34347b5 100644
> > --- a/meta/classes/debianize.bbclass
> > +++ b/meta/classes/debianize.bbclass
> > @@ -15,7 +15,9 @@ MAINTAINER ??= "Unknown maintainer
> > <unknown@example.com>" deb_add_changelog() {
> >         changelog_v="${CHANGELOG_V}"
> >         timestamp=0
> > -       if [ -f ${S}/debian/changelog ]; then
> > +       # we have a changelog and that is not autogenerated
> > +       # (when autogenerated, changelog.orig is empty)
> > +       if [ -f ${S}/debian/changelog ] && [ -s
> > ${WORKDIR}/changelog.orig ]; then if [ ! -f
> > ${WORKDIR}/changelog.orig
> 
> can that condition inside the condition still be met?

Yes, this is met when a custom changelog file is provided and we run
the deb_add_changelog function for the first time. There, no
changelog.orig exists yet.

Felix

> 
> Henning
> 
> > ]; then cp ${S}/debian/changelog ${WORKDIR}/changelog.orig
> >                 fi
> > @@ -34,10 +36,12 @@ ${PN} (${changelog_v}) UNRELEASED; urgency=low
> >  
> >   -- ${MAINTAINER}  ${date}
> >  EOF
> > -       if [ -f ${WORKDIR}/changelog.orig ]; then
> > -               # prepend our entry to the original changelog
> > -               echo >> ${S}/debian/changelog
> > -               cat ${WORKDIR}/changelog.orig >>
> > ${S}/debian/changelog
> > +       # ensure that we always start with the orig version of the
> > +       # changelog on repeated invocations (e.g. on partial
> > rebuilds)
> > +       touch ${WORKDIR}/changelog.orig
> > +       # prepend our entry to the original changelog
> > +       echo >> ${S}/debian/changelog
> > +       cat ${WORKDIR}/changelog.orig >> ${S}/debian/changelog
> >         fi
> >  
> >         if [ -f ${WORKDIR}/changelog ]; then
>