Bug#862116: dpkg-dev: Set BUILD_PATH_PREFIX_MAP for build tools to generate reproducible output

[Ximin Luo]

Package: dpkg-dev
Version: 1.18.23.0~reproducible2
Severity: wishlist
Tags: patch
User: reproducible-builds at lists.alioth.debian.org
Usertags: build-path 

Dear Maintainer,

I've been asked to file this bug report so that others working on the
Reproducible Builds project can better track the ongoing issue of
build-path-independent reproducibility in various tools and compilers. I don't
mean to imply to rush this process nor pressure you, this report is only for
informational purposes.

As you know, I've already contacted GCC upstream with a proposed patch:
- https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00513.html

This is being tracked in Debian here:
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=862113

I have some patches for dpkg that accompany the GCC patch, which may be browsed
as git commits here:
- https://anonscm.debian.org/cgit/reproducible/dpkg.git/log/?h=pu/reproducible_builds

The built packages may be downloaded here:
- https://reproducible.alioth.debian.org/debian/
- https://tests.reproducible-builds.org/debian/index_repositories.html (overview)

The reproducibility status of dependent packages is being tracked on these pages:
- https://tests.reproducible-builds.org/debian/issues/unstable/captures_build_path_issue.html

We're currently waiting for the GCC patch to be accepted and backported to
Debian. Guillem (dpkg maintainer) has said this dpkg patch mostly looks good,
needing just a few minor adjustments that I need to go dig back out of my IRC
logs, which I will do when the GCC patch gets accepted upstream.

Finally, note that this patch will probably supersede
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=827155

Ximin

-- System Information:
Debian Release: 9.0
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable-debug'), (500, 'testing-debug'), (300, 'unstable'), (200, 'experimental'), (1, 'experimental-debug')
Architecture: amd64
 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages dpkg-dev depends on:
ii  binutils      2.28-4
ii  bzip2         1.0.6-8.1
ii  libdpkg-perl  1.18.23.0~reproducible2
ii  make          4.1-9.1
ii  patch         2.7.5-1+b2
pn  perl:any      <none>
ii  tar           1.29b-1.1
ii  xz-utils      5.2.2-1.2+b1

Versions of packages dpkg-dev recommends:
ii  build-essential          12.3
ii  clang-3.9 [c-compiler]   1:3.9.1-8
ii  fakeroot                 1.21-3.1
ii  gcc [c-compiler]         4:6.3.0-4
ii  gcc-6 [c-compiler]       6.3.0-16
ii  gnupg                    2.1.18-6
ii  gnupg2                   2.1.18-6
ii  gpgv                     2.1.18-6
ii  libalgorithm-merge-perl  0.08-3

Versions of packages dpkg-dev suggests:
ii  debian-keyring  2017.01.20

-- no debconf information