Notes for python2.7 - reproducible builds result

Version annotated: 2.7.10-2
Identified issues:
Identifier: randomness_in_fat_lto_objects
URL https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66305
Description Objects built with `gcc -flto -ffat-lto-objects` will contain random strings
in the form of `.gnu.lto_.inline.24c30dabb443e726`. They will change at
each build.
Temporary (?) solution: pass the full path of the source as the argument
to `-frandom-seed`.
Identifier: captures_kernel_version
Description Stores the kernel version (uname -a, /proc/version, etc.) output, normally for debugging purposes.
.
Sub-issue: captures_kernel_version_via_CMAKE_SYSTEM
Identifier: records_build_flags
Description Records $CFLAGS, which vary intentionally due to the «-fdebug-prefix-map=${BUILDPATH}=.»,
«-ffile-prefix-map=${BUILDPATH}=.» or «-fmacro-prefix-map=${BUILDPATH}=.» flags.
.
We have a patch pending to GCC to fix this issue centrally:
.
https://gcc.gnu.org/ml/gcc-patches/2016-11/msg00182.html
.
Though the patch is currently unlikely to be merged. If/when this
is accepted, this issue should be fixed for all packages and you
should not need to fix it specifically in your package.
.
There is also a work-in-progress patch to dpkg that could address this issue:
.
https://bugs.debian.org/985553
.
For more background information see:
.
• https://alioth-lists.debian.net/pipermail/reproducible-builds/Week-of-Mon-20160822/006788.html
• https://alioth-lists.debian.net/pipermail/reproducible-builds/Week-of-Mon-20160905/006984.html
• https://alioth-lists.debian.net/pipermail/reproducible-builds/Week-of-Mon-20160912/007076.html
Comments: Test result in python2.7-dev, but this is already deactivated
on buildds or when `nobench` is given in `DEB_BUILD_OPTIONS`.
Guess it could be made turned off by defaults? Also, it
doesn't show up for python3.4 and python3.5, but not
investigated.
 

Our notes about issues affecting packages are stored in notes.git and are targeted at packages in Debian in 'unstable/amd64' (unless they say otherwise).