[OE-core] [PATCH 0/1] python-xcbgen: improve reproducibility

[Juro Bystricky]

This patch addresses the last remaining non-reproducible package for
core-image-minimal (with current "sumo").

A short explanation:
When building core-image-minimal in two different folders with current "sumo"
(http://git.yoctoproject.org/cgit/cgit.cgi/poky/log/?h=sumo ) :

$ source oe-build-env build_1
local.conf:
PACKAGE_CLASSES="package_deb package_rpm package_ipk"
MACHINE="qemux86-64"
$ bitbake core-image-minimal

and

$ source oe-build-env build_2

local.conf:
PACKAGE_CLASSES="package_deb package_rpm package_ipk"
MACHINE="qemux86-64"

$ bitbake core-image-minimal

After binary comparing all packages in build_1/tmp/deploy/[ipk,rpm.deb] to
build_2/tmp/deploy/[ipk,rpm,deb], we get these results:

           IPK   DEB  RPM
Same:         0    0    0
Different: 3952 3952 3952
Total:     3952 3952 3952

Repeating the same with (same host):

$ source oe-build-env build_repro_1
local.conf:
PACKAGE_CLASSES="package_deb package_rpm package_ipk"
MACHINE="qemux86-64"
INHERIT+="reproducible_build"
$ bitbake core-image-minimal

and

$ source oe-build-env build_repro_2

local.conf:
PACKAGE_CLASSES="package_deb package_rpm package_ipk"
MACHINE="qemux86-64"
INHERIT+="reproducible_build"

$ bitbake core-image-minimal

After binary comparing all packages in build_repro_1/tmp/deploy/[ipk,rpm.deb] to
build_repro_2/tmp/deploy/[ipk,rpm,deb], we get these results:

           IPK   DEB  RPM
Same:      3951 3951 3951
Different:    1    1    1
Total:     3952 3952 3952

The remaining package that does not build reproducibly is python-xcbgen.
This is because the package contains .pyc files which contain build-time timestamps.
The python files are compiled with host Python3, which may or may not support
SOURCE_DATE_EPOCH. However, both oe-core python-native and python3-native do support
SOURCE_DATE_EPOCH, so to build the package reproducibly all we need to do is
compile the python files with python3-native. Ideally, we would use python3-native
unconditionally, but building python3-native itself can be computationally quite expensive.
So, as a compromise, we use python3-native only when BUILD_REPRODUCIBLE_BINARIES = '1'
host Python3 otherwise.


Juro Bystricky (1):
  python-xcbgen_1.12: improve reproducibility

 meta/recipes-graphics/xorg-proto/xcb-proto_1.12.bb | 5 +++++
 1 file changed, 5 insertions(+)

-- 
2.7.4