Re: [pacman-dev] [PATCH 5/5] makepkg: unify source file times for improved build reproducibility

On 05/12/17 at 12:41pm, Levente Polyak wrote:

Signed-off-by: Levente Polyak --- scripts/makepkg.sh.in | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/scripts/makepkg.sh.in b/scripts/makepkg.sh.in index bd92c526..83c80fa7 100644 --- a/scripts/makepkg.sh.in +++ b/scripts/makepkg.sh.in @@ -1731,6 +1731,9 @@ if (( !REPKG )); then if (( PREPAREFUNC )); then run_prepare fi + + # unify source times before building for reproducibility + find "$srcdir" -exec touch -h -d "@${SOURCE_DATE_EPOCH}" {} + fi

if (( PKGVERFUNC )); then

I'm still not convinced we should be doing this in makepkg and I'm not sure exactly where our disagreement about this is at this point. So, let me describe how I would handle reproducible packages and you can tell me why your approach is better. First, I'm only concerned about manipulating things that makepkg is not directly responsible for. Anything that improves the reproducibility of makepkg's own output is fine (e.g. removing the timestamp from .PKGINFO and .MTREE files). Beyond that, I don't think makepkg is the place for trying to make a package reproducible. We seem to be in agreement that a separate script will be necessary to actually reproduce a built package. I would say that the same script should be used to build the original package in the first place. Aside from the fact that changes like this break existing usage patterns for makepkg, makepkg is never going to be able to guarantee that a package is reproducible. There are simply too many variables that can influence the resulting package for makepkg to ever record them all. Building a package that is reproducible requires a controlled environment. The script that handles reproducing the package has to be able to setup such an environment, so why not let it setup the environment for the initial build? People that don't care about the reproducibility of the resulting package can continue to use makepkg as they do now and those that do care can use the wrapper script to build it. And, makepkg doesn't have to concern itself with reproducibility beyond making sure that its own output is reproducible. Such a script could handle the timestamp manipulation in this patch. We already provide several makepkg options to control which steps are run. The wrapper would invoke makepkg once to extract/prepare the sources, the wrapper would then adjust the timestamps itself, finally it would invoke makepkg again to continue the build. apg