[libcamera-devel] [PATCH] libcamera: Add build time to version string

[Laurent Pinchart]

Hi Kieran,

On Wed, Aug 05, 2020 at 03:34:01PM +0100, Kieran Bingham wrote:
> On 05/08/2020 15:29, Laurent Pinchart wrote:
> > On Wed, Aug 05, 2020 at 02:57:00PM +0200, Niklas Söderlund wrote:
> >> Having the build time in the version string is useful when building from
> >> a dirty worktree and deploying to targets as a quick way to identify the
> >> binary have been deployed successfully.
> >>
> >> Before this change the version string is reported as
> >>
> >>     libcamera v0.0.0+1692-aaff196a-dirty
> >>
> >> While with this change the version string is reported as
> >>
> >>     libcamera v0.0.0+1692-aaff196a-dirty 2020-08-05T12:55:11+00:00
> >>
> >> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> > 
> > This will get in the way of reproducible builds, especially for tagged
> > releases. I would at least restrict this feature to dirty builds, and
> > even then, I'll let Kieran comment on whether reproducible builds are
> > important.
> 
> I think I recall determining that reproducible builds were already
> broken due to the way meson handles RPATH/RUNPATH.
> 
> I too frequently use the version string to make sure I am running the
> same code I expect, and having a build-time stamp in there (for debug)
> builds would be quite nice.
> 
> Restricting this to DEBUG builds might be quite nice, then release
> builds from packagers just get a clean version.
> 
> Adding only for release builds also removes any worries of reproducible
> builds from the equation anyway ;-)

Would adding a timestamp for dirty builds be more generic ? Presumably
if the working tree is clean you don't need to differentiate between
different builds with the same commti sha1, as they should all be the
same :-)

> >> ---
> >>  utils/gen-version.sh | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/utils/gen-version.sh b/utils/gen-version.sh
> >> index 7f7872ceba7b038a..93bc97d6d8a8a24a 100755
> >> --- a/utils/gen-version.sh
> >> +++ b/utils/gen-version.sh
> >> @@ -32,4 +32,6 @@ git diff-index --quiet HEAD || version="$version-dirty"
> >>  # of the git SHA1 and remove the initial 'v'.
> >>  version=$(echo "$version" | sed -e 's/-/+/' | sed -e 's/-g/-/' | cut -c 2-)
> >>  
> >> -echo "$version"
> >> +buildtime=$(date --iso-8601=seconds --utc)
> >> +
> >> +echo "$version $buildtime"

-- 
Regards,

Laurent Pinchart