Re: DTC Version and Reproducible Builds

["david@gibson.dropbear.id.au" <david@gibson.dropbear.id.au>]

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On Mon, Sep 23, 2024 at 12:46:20PM +0200, Andreas Gnau wrote:
> On Mon, Sep 16, 2024 at 07:51:31PM +0000, Anthony Ortega wrote:
> > I am trying to generate reproducible builds for a Linux environment
> > using Buildroot. One of the last packages that is giving me trouble
> > is the DTC programs.
> > [...]
> > They all seem to intend to encode the git
> > version of the package they were pulled from. However, in a build
> > system such as Buildroot the DTC source is staged in such a way that
> > the git information is stripped away. While that in of itself is not
> > a problem, the problem is that it may be getting built in an output
> > directory that is within a larger git repository. Therefore, when
> > the setlocalversion script runs, it ends up pulling the version of
> > this larger git repository.
> 
> Yocto/OpenEmbedded[1] and OpenWrt[2] avoid such issues by setting
> GIT_CEILING_DIRECTORIES. Maybe buildroot could do the same and fix it for
> all packages, not just dtc tools?

Oh, I didn't know about GIT_CEILING_DIRECTORIES.  That does indeed
sound look a good idea.

> [1] https://git.openembedded.org/openembedded-core/tree/meta/conf/bitbake.conf?id=bb3101fffceacfa4c021c33affb7c785da8d859f#n788
> 
> [2] https://git.openwrt.org/?p=openwrt/openwrt.git;a=blob;f=include/package.mk;h=7fbecf98dc7c9a5b11ce1958e254578f7e4d9c73;hb=7850e197670afff38426075953ba6a71f0f431c8#l202
> 
> On 2024-09-20 13:05, david@gibson.dropbear.id.au wrote:
> > Unfortunately, I don't think our system can be configured to use
> > meson without a massive overhaul. In the short term I've applied a
> > patch in our build that removes the line that grabs the commit tag
> > during build.
> 
> On Thu, Sep 19, 2024 at 09:45:04PM +0000, Anthony Ortega wrote:
> > But, in any case, I wasn't suggesting this as a practical workaround,
> > but more as a diagnostic.  If it works with meson we can look closer
> > at what it's doing and maybe duplicate it with make.
> 
> I do not know what other projects do, but most likely those that do not
> exhibit this issue, set the git-dir explicitly (or use GIT_CEILING_DIRS) to
> avoid git taking some repository above the source directory.
> 
> I still think as a first thing, buildroot should implement a generic
> solution and then we can look into fixing dtc and tools.
> 
> Regards, Andreas
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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