[rb-general] Making CMake packages reproducible

[Geert Stappers]

On Tue, Oct 02, 2018 at 01:47:53PM +0200, Peter Wu wrote:
> Hi!
> 
> While working on making a package reproducible that uses CMake as build
> system (wireshark on Arch Linux, but in a smaller form, x265 in Debian),
> I found one feature of CMake that makes packages non-reproducible if the
> build directory changes. If a project:
> 
> 1) builds with a shared library
> 2) and has an executable linking with that library
> 3) then CMake will link with -Wl,-rpath,$builddir
> 4) and .build-id will be different
> 5) on install, the rpath is stripped, but build-id remains unchanged.
> 
> For example, building x265 on Debian sid reveals:
> 
>     [100%] Linking CXX executable x265
>     /usr/bin/c++  -g -O2 -fdebug-prefix-map=/home/user/x1/x265-2.8=.
>     [..] CMakeFiles/cli.dir/x265.cpp.o
>     -o x265 -Wl,-rpath,/home/user/x1/x265-2.8/x265-8bit: libx265.so.160 [..]
>     [..]
>     -- Installing: /home/user/x1/x265-2.8/debian/tmp/usr/bin/x265
>     -- Set runtime path of "/home/user/x1/x265-2.8/debian/tmp/usr/bin/x265" to ""
> 
> To avoid the rpath from being set, use cmake -DCMAKE_SKIP_RPATH=ON. This
> used to be done by default when using debhelper, but was removed in
> https://bugs.debian.org/538977 due to test programs that relied on the
> library path to be set.
> 
> Would it make sense to set it by default in debhelper? Projects that
> have tests depending on the rpath location can either override
> -DCMAKE_SKIP_RPATH=OFF (making the build path part of the build
> environment) or set LD_LIBRARY_PATH. Or should every package include
> this option? (This question applies both to Debian and Arch Linux).
 
Seems a valid question to me.
Also addressed to the right mailinglist.
Now I wonder why it was replied with silence.



Groeten
Geert Stappers
-- 
Leven en laten leven