DeveloperWiki:Building in a Clean Chroot
This article is part of the DeveloperWiki.
Building in a clean chroot prevents missing dependencies in packages, whether due to unwanted linking or packages missing in the depends array in the PKGBUILD. It also allows users to build a package for the stable repositories (core, extra, community) while having packages from [testing] installed.
To quickly build a package in a clean chroot without any further tinkering, one can use the helper scripts from the devtools package.
These helper scripts should be called in the same directory where the PKGBUILD is, just like with makepkg. For instance, extra-x86_64-build automatically sets up a chroot from a clean chroot matrix in /var/lib/archbuild, updates it, and builds a package for the extra repository. For multilib builds there is just multilib-build without an architecture. Consult the table below for information on which script to use when building for a specific repository and architecture.
The -c parameter resets the chroot matrix, which can be useful in case of breakage. It is not needed for building in a clean chroot.
|Target repository||Architecture||Build script to use||Pacman configuration file used|
|extra / community||x86_64||extra-x86_64-build||/usr/share/devtools/pacman-extra.conf|
|testing / community-testing||x86_64||testing-x86_64-build||/usr/share/devtools/pacman-testing.conf|
|staging / community-staging||x86_64||staging-x86_64-build||/usr/share/devtools/pacman-staging.conf|
Setting Up A Chroot
The devtools package provides tools for creating and building within clean chroots. Install it if not done already.
To make a clean chroot, create a directory in which the chroot will reside. For example, $HOME/chroot.
$ mkdir ~/chroot
Define the CHROOT variable:
Now create the chroot (the sub directory root is required because the $CHROOT directory will get other sub directories for clean working copies):
# mkarchroot $CHROOT/root base-devel
Edit ~/.makepkg.conf to set the packager name and any makeflags. Also adjust the mirrorlist in $CHROOT/root/etc/pacman.d/mirrorlist and enable the testing repository in $CHROOT/root/etc/pacman.conf, if desired.
Alternatively, provide a custom pacman.conf and makepkg.conf with the following:
# mkarchroot -C <pacman.conf> -M <makepkg.conf> $CHROOT/root base-devel
Building in the Chroot
Firstly, make sure the chroot is up to date with:
# arch-nspawn $CHROOT/root pacman -Syu
Then, to build a package in the chroot, run the following from the dir containing the PKGBUILD:
$ makechrootpkg -c -r $CHROOT
Passing the -c flag to makechrootpkg ensures that the working chroot (named $CHROOT/$USERNAME) is cleaned before building starts.
Manual package installation
Packages can be installed manually to the working chroot by using:
# makechrootpkg -r $CHROOT -I package-1.0-1-x86_64.pkg.tar.xz
If done from a directory that contains a PKGBUILD, the package will then be built. Avoid being in such a directory if you want to just install the package.
Installation after building
Tell makechrootpkg to simply install a package to the rw layer of the chroot after building by passing the -i arg. Unrecognized args get passed to makepkg, so this calls `makepkg` with the -i arg.
# makechrootpkg -r $CHROOT -- -i
Handling Major Rebuilds
The cleanest way to handle a major rebuild is to use the [staging] repositories. Build the first package against [extra] and push it to [staging]. Then rebuild all following packages against [staging] and push them there.
If you can't use [staging], you can build against custom packages using a command like this:
# extra-x86_64-build -- -I ~/packages/foobar/foobar-2-1-any.pkg.tar.xz
You can specify more than one package to be installed using multiple -I arguments.
A simpler, but dirtier way to handle a major rebuild is to install all built packages in the chroot, never cleaning it. Build the first package using:
And build all following packages using:
# makechrootpkg -n -r /var/lib/archbuild/extra-x86_64
Running namcap (the -n argument) implies installing the package in the chroot. *-build also does this by default.