Streamline build-packages-locally article

[BAMF0]

Description

This pull request will streamline the article "How to build packages locally" by making it propose one recommended and more authoritative way of building packages using sbuild, rather than multiple. It is needed to provide a more up to date and direct instruction set that should allow contributor's to build packages in a more uniform way.

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Related issue

• Fixes: Streamline 'local build' instructions #318

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Checklist

• I have read and followed the Ubuntu Project contributing guide
• My pull request is linked to an existing issue (if applicable)
• I have tested my changes, and they work as expected

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Additional notes (optional)

Configuration files as code blocks do not allow copying hashes ("#"), which is currently a UX bug since the text has to be manually copied instead.

[BAMF0]

Force pushed for typo correction

[rkratky]

Thank you, @BAMF0! I wanted to suggest a bit more involved formatting changes, so I submitted my review in the form of a PR against your branch at BAMF0#1

[BAMF0]

@rkratky Nice, thanks! I appreciate the changes. Let me have a look.

[BAMF0]

Merged your changes now, the looked good to me.

[jbicha]

You need to fix #270 if you're going to recommend unshare and ~/.config/sbuild/sbuild.pl` since otherwise the instructions won't work with the current Ubuntu LTS.

See my notes from #295

I don't think enabling experimental tags (-E) is useful for beginners. Lintian already complains about too many things (which is slowly being improved), so we shouldn't add additional warnings that the Lintian maintainers don't recommend and aren't needed even for main inclusion review.

The purge config is unnecessary for unshare, but it is helpful if you're going to use schroot for cross building.

$build_dir = '/home/my_user/schroot/build';
$log_dir = '/home/my_user/schroot/logs';

I don't think this should mention schroot. In my testing, I noticed that the log directory must exist for sbuild to store logs there.

[BAMF0]

@jbicha Great points! Thanks for the feedback. It's really easy to assume everything from the perspective of the bleeding edge release, however that also risks these incompatibilities you mentioned here.

In this case, I think the way forward is fixing #270 as you suggested, saying in build-packages-locally.rst that the unshare backend requires 25.10 or later (as 25.04 is EOL), and making a note that it can also be used on 24.04 LTS but only if noble-backports is added to the apt sources.

[mwhudson]

Here's a few unsolicited comments! I think the changes mostly go in the right direction but some things are a bit muddled. It probably makes sense to document the new shiny unshare backend and then have a section that says "on older releases set up schroot like a b c"? (I think it's just a touch premature to drop all documentation of the schroot based solution).

[paride]

With this ~/.config/sbuild/config.pl I can just sbuild or sbuild -d <release> most of the time, and it just works:

$chroot_mode = 'unshare';
$unshare_mmdebstrap_keep_tarball = 1;

# /tmp is tmpfs and large builds will fail after filling all memory.
$unshare_tmpdir_template = '/var/tmp/tmp.sbuild.XXXXXXXXXX';

$clean_source = 0;
$run_lintian = 0;

[rkratky]

Thank you, @BAMF0. A few more suggestions.

[BAMF0]

Hey folks! In order to get things moving, we are planning to get this merged and move the current unresolved comments into a separate issue in order to keep track of them. I will link the new issue here once it has been created.

[BAMF0]

Here is the new issue: #536

For ease of use, I have linked the unresolved comments as well in there.

[rkratky]

Thanks!