perl: run builds from a pristine source tree

Running builds from a previously used directory relies on correctness of
'make clean' or incremental 'make', and sadly perl (or perl-cross) does not have either.

The particularly nasty problem, currently occurring, is that sometimes, when reusing
a previous build, we arrive at a combination of timestamps in the tree,
where make becomes very confused, gets lost in its own rules and enters an infinite loop,
never figuring out what needs to be rebuild in what order. Worse, there is no reliable
trigger for this that was found, and any attempts to 'isolate the issue' haven't produced one.

Let's simply add a clean S/B separation for builds, and always run a build from a reproducible
set of files.

[YOCTO #14902]

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
---
 ...ctly-list-modules-when-cleaning-them.patch | 24 ----------------
 ...file-do-not-clean-config.h-xconfig.h.patch | 28 -------------------
 .../perl-cross/perlcross_1.4.bb               |  2 --
 meta/recipes-devtools/perl/perl_5.36.0.bb     |  8 ++++--
 4 files changed, 5 insertions(+), 57 deletions(-)
 delete mode 100644 meta/recipes-devtools/perl-cross/files/0001-Makefile-correctly-list-modules-when-cleaning-them.patch
 delete mode 100644 meta/recipes-devtools/perl-cross/files/0001-Makefile-do-not-clean-config.h-xconfig.h.patch

> -----Original Message-----
> From: openembedded-core@lists.openembedded.org <openembedded-core@lists.openembedded.org> On Behalf Of Alexander Kanavin
> Sent: den 31 augusti 2022 11:19
> To: openembedded-core@lists.openembedded.org
> Cc: Alexander Kanavin <alex@linutronix.de>
> Subject: [OE-core] [PATCH] perl: run builds from a pristine source tree
> 
> Running builds from a previously used directory relies on correctness of
> 'make clean' or incremental 'make', and sadly perl (or perl-cross) does
> not have either.
> 
> The particularly nasty problem, currently occurring, is that sometimes, when reusing
> a previous build, we arrive at a combination of timestamps in the tree,
> where make becomes very confused, gets lost in its own rules and enters an infinite loop,
> never figuring out what needs to be rebuild in what order. Worse, there is no reliable
> trigger for this that was found, and any attempts to 'isolate the issue' haven't produced one.
> 
> Let's simply add a clean S/B separation for builds, and always run a build from a reproducible
> set of files.
> 
> [YOCTO #14902]
> 
> Signed-off-by: Alexander Kanavin <alex@linutronix.de>
> ---
>  ...ctly-list-modules-when-cleaning-them.patch | 24 ----------------
>  ...file-do-not-clean-config.h-xconfig.h.patch | 28 -------------------
>  .../perl-cross/perlcross_1.4.bb               |  2 --
>  meta/recipes-devtools/perl/perl_5.36.0.bb     |  8 ++++--
>  4 files changed, 5 insertions(+), 57 deletions(-)
>  delete mode 100644 meta/recipes-devtools/perl-cross/files/0001-Makefile-correctly-list-modules-when-cleaning-them.patch
>  delete mode 100644 meta/recipes-devtools/perl-cross/files/0001-Makefile-do-not-clean-config.h-xconfig.h.patch

[cut]

> diff --git a/meta/recipes-devtools/perl/perl_5.36.0.bb b/meta/recipes-devtools/perl/perl_5.36.0.bb
> index ead7dace16..2dc558aaa5 100644
> --- a/meta/recipes-devtools/perl/perl_5.36.0.bb
> +++ b/meta/recipes-devtools/perl/perl_5.36.0.bb
> @@ -28,7 +28,7 @@ SRC_URI:append:class-target = " \
> 
>  SRC_URI[perl.sha256sum] = "e26085af8ac396f62add8a533c3a0ea8c8497d836f0689347ac5abd7b7a4e00a"
> 
> -S = "${WORKDIR}/perl-${PV}"
> +B = "${WORKDIR}/perl-${PV}-build"

Any reason not to just set B = "${WORKDIR}/build" ?

> 
>  inherit upstream-version-is-even update-alternatives
> 
> @@ -48,7 +48,10 @@ export ENC2XS_NO_COMMENTS = "1"
>  CFLAGS += "-D_GNU_SOURCE -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64"
> 
>  do_configure:prepend() {
> -    cp -rfp ${STAGING_DATADIR_NATIVE}/perl-cross/* ${S}
> +    rm -rf ${B}
> +    cp -rfp ${S} ${B}
> +    cp -rfp ${STAGING_DATADIR_NATIVE}/perl-cross/* ${B}
> +    cd ${B}
>  }
> 
>  do_configure:class-target() {
> @@ -116,7 +119,6 @@ print(datetime.fromtimestamp($SOURCE_DATE_EPOCH, timezone.utc).strftime('%a %b %
>              ")"
>          echo "#define PERL_BUILD_DATE \"$PERL_BUILD_DATE\"" >> config.h
>      fi
> -    oe_runmake clean
>  }
> 
>  do_compile() {
> --
> 2.30.2

//Peter

On Wed, 31 Aug 2022 at 12:24, Peter Kjellerstedt
<peter.kjellerstedt@axis.com> wrote:
> > -S = "${WORKDIR}/perl-${PV}"
> > +B = "${WORKDIR}/perl-${PV}-build"
>
> Any reason not to just set B = "${WORKDIR}/build" ?

'build' is a convention set by cmake/autotools/etc classes, not
globally, and it implies the original source is not in it, which is
not the case here.

Alex