Add variant mechanism to build temporary packages.

Build some variants for gnome, to demonstrate how:
- nopulse
- an "I'm feeling lucky" mode that randomly attempts to build one of the
  ten thousand packages with stable keywords that isn't yet installed
  via autounmask
- compile some unstable compilers via --buildpkgonly. Nothing is ever
  installed or can mix with the system, so it cannot ever have an effect
  on other binhost packages. But users can install upcoming compilers
  for testing.

Variant builds are built in an ephemeral nspawn container based on the
original one. The primary build has to succeed in order to build a
variant, otherwise we assume resolution fails anyway. The ephemeral
container means we can freely modify the portage config, even in totally
broken ways, and our changes get automatically wiped after exiting. The
only persistent data is the binpkgs cache, which is mounted from the
real location.

Signed-off-by: Eli Schwartz <eschwartz@gentoo.org>

11 files changed, 112 insertions, 7 deletions

diff --git a/builders/milou/binhost-update b/builders/milou/binhost-update
index 8a304dd..d48e15e 100755
--- a/builders/milou/binhost-update
+++ b/builders/milou/binhost-update
@@ -113,15 +113,26 @@ emerge --sync -q &>> ${TMPFILE}
 
 anyfail=0
 
+nspawn_command=(systemd-nspawn --bind /var/cache/distfiles --bind-ro /var/db/repos/gentoo --tmpfs=/var/tmp:mode=1777,size=${TMPFS_SIZE}g)
 for n in ${NSPAWN_NAMES} ; do
+	machinedir=/var/lib/machines/${n}
 	echo Machine ${n} &>> ${TMPFILE}
 	echo &>> ${TMPFILE}
-	cd /var/lib/machines/${n}/etc/binhost &>> ${TMPFILE}
+	cd ${machinedir}/etc/binhost &>> ${TMPFILE}
 	git reset --hard &>> ${TMPFILE}
 	git pull &>> ${TMPFILE}
 	cd /root &>> ${TMPFILE}
-	systemd-nspawn --bind /var/cache/distfiles --bind-ro /var/db/repos/gentoo --tmpfs=/var/tmp:mode=1777,size=${TMPFS_SIZE}g -M ${n} /root/bin/run-update &>> ${TMPFILE}
-	let "anyfail+=$?"
+	"${nspawn_command[@]}" -M ${n} /root/bin/run-update &>> ${TMPFILE}
+	ret=$?
+	let "anyfail+=${ret}"
+	if [[ ${ret} = 0 ]]; then
+		builder=$(readlink ${machinedir}/etc/portage)
+		for variant in ${machinedir}/${builder}/variants/*; do
+			[[ -d ${variant} ]] || break
+			"${nspawn_command[@]}" --ephemeral --bind ${machinedir}/var/cache/binpkgs -M ${n} /root/bin/run-update ${variant##*/} &>> ${TMPFILE}
+			let "anyfail+=$?"
+		done
+	fi
 done
 
 
diff --git a/builders/milou/gnome-23/portage/variants/lucky/.run_marker b/builders/milou/gnome-23/portage/variants/lucky/.run_marker
new file mode 100644
index 0000000..722c3eb
--- /dev/null
+++ b/builders/milou/gnome-23/portage/variants/lucky/.run_marker
@@ -0,0 +1 @@
+I'm feeling lucky!
diff --git a/builders/milou/gnome-23/portage/variants/nopulse/package.use/nopulse b/builders/milou/gnome-23/portage/variants/nopulse/package.use/nopulse
new file mode 100644
index 0000000..3f33baa
--- /dev/null
+++ b/builders/milou/gnome-23/portage/variants/nopulse/package.use/nopulse
@@ -0,0 +1 @@
+*/* -pulseaudio -screencast
diff --git a/builders/milou/gnome-23/portage/variants/unstable/buildpkgonly b/builders/milou/gnome-23/portage/variants/unstable/buildpkgonly
new file mode 100755
index 0000000..e344f3c
--- /dev/null
+++ b/builders/milou/gnome-23/portage/variants/unstable/buildpkgonly
@@ -0,0 +1,9 @@
+#!/bin/bash
+set -e
+
+# We must use buildpkgonly here since we do not want to actually install
+# unstable packages. buildpkgonly will fatally error if any dependencies aren't
+# installed.
+emerge --buildpkgonly sys-devel/gcc:15 sys-devel/gcc:14 sys-devel/gcc:12
+# ... and clean it up
+rm /etc/portage/package.accept_keywords/gcc
diff --git a/builders/milou/gnome-23/portage/variants/unstable/package.accept_keywords/gcc b/builders/milou/gnome-23/portage/variants/unstable/package.accept_keywords/gcc
new file mode 100644
index 0000000..8b9d7eb
--- /dev/null
+++ b/builders/milou/gnome-23/portage/variants/unstable/package.accept_keywords/gcc
@@ -0,0 +1,2 @@
+sys-devel/gcc ~amd64
+<sys-devel/gcc-15.0.9999:15 **
diff --git a/builders/milou/gnome-23/run-update b/builders/milou/gnome-23/run-update
index 02cdf8a..84bf589 100755
--- a/builders/milou/gnome-23/run-update
+++ b/builders/milou/gnome-23/run-update
@@ -3,6 +3,40 @@
 # if one thing fails, abort entirely
 set -e
 
-emerge -uDNkq --changed-deps --backtrack=100 --keep-going world
+to_install=(world)
 
-emerge --depclean --quiet-unmerge-warn
+if [[ $1 = lucky ]]; then
+	eix-update
+	eix --stable --only-names | grep -E -v '^(acct|virtual|sec)-' | sort -u > /tmp/stable
+	eix --installed --only-names | sort -u > /tmp/installed
+	comm -23 /tmp/stable /tmp/installed > /tmp/uninstalled-stable
+	sed -i 's/--binpkg-respect-use//' /etc/portage/make.conf
+
+	to_install=(--autounmask --autounmask-keep-keywords --autounmask-write --autounmask-continue $(shuf -n1 /tmp/uninstalled-stable))
+elif [[ $1 ]]; then
+	pushd /etc/portage/variants/$1
+	while read -r -d '' line; do
+		dest=../../${line%.footer}
+		if [[ ${line} = world* ]]; then
+			dest=/var/lib/portage/world
+		fi
+
+		if [[ ${line} = world.remove ]]; then
+			emerge -C $(<"${line}")
+		elif [[ ${line} = *.footer ]]; then
+			cat "${line}" >> "${dest}"
+		else
+			cp "${line}" "${dest}"
+		fi
+	done < <(find . -type f -printf '%P\0')
+	if [[ -f buildpkgonly ]]; then
+		./buildpkgonly
+	fi
+	popd
+fi
+
+emerge -uDNkq --changed-deps --backtrack=100 --keep-going "${to_install[@]}"
+
+if [[ ! $1 ]]; then
+	emerge --depclean --quiet-unmerge-warn
+fi
diff --git a/builders/milou/gnome-v3-23/portage/variants/lucky/.run_marker b/builders/milou/gnome-v3-23/portage/variants/lucky/.run_marker
new file mode 100644
index 0000000..722c3eb
--- /dev/null
+++ b/builders/milou/gnome-v3-23/portage/variants/lucky/.run_marker
@@ -0,0 +1 @@
+I'm feeling lucky!
diff --git a/builders/milou/gnome-v3-23/portage/variants/nopulse/package.use/nopulse b/builders/milou/gnome-v3-23/portage/variants/nopulse/package.use/nopulse
new file mode 100644
index 0000000..3f33baa
--- /dev/null
+++ b/builders/milou/gnome-v3-23/portage/variants/nopulse/package.use/nopulse
@@ -0,0 +1 @@
+*/* -pulseaudio -screencast
diff --git a/builders/milou/gnome-v3-23/portage/variants/unstable/buildpkgonly b/builders/milou/gnome-v3-23/portage/variants/unstable/buildpkgonly
new file mode 100755
index 0000000..e344f3c
--- /dev/null
+++ b/builders/milou/gnome-v3-23/portage/variants/unstable/buildpkgonly
@@ -0,0 +1,9 @@
+#!/bin/bash
+set -e
+
+# We must use buildpkgonly here since we do not want to actually install
+# unstable packages. buildpkgonly will fatally error if any dependencies aren't
+# installed.
+emerge --buildpkgonly sys-devel/gcc:15 sys-devel/gcc:14 sys-devel/gcc:12
+# ... and clean it up
+rm /etc/portage/package.accept_keywords/gcc
diff --git a/builders/milou/gnome-v3-23/portage/variants/unstable/package.accept_keywords/gcc b/builders/milou/gnome-v3-23/portage/variants/unstable/package.accept_keywords/gcc
new file mode 100644
index 0000000..8b9d7eb
--- /dev/null
+++ b/builders/milou/gnome-v3-23/portage/variants/unstable/package.accept_keywords/gcc
@@ -0,0 +1,2 @@
+sys-devel/gcc ~amd64
+<sys-devel/gcc-15.0.9999:15 **
diff --git a/builders/milou/gnome-v3-23/run-update b/builders/milou/gnome-v3-23/run-update
index 02cdf8a..84bf589 100755
--- a/builders/milou/gnome-v3-23/run-update
+++ b/builders/milou/gnome-v3-23/run-update
@@ -3,6 +3,40 @@
 # if one thing fails, abort entirely
 set -e
 
-emerge -uDNkq --changed-deps --backtrack=100 --keep-going world
+to_install=(world)
 
-emerge --depclean --quiet-unmerge-warn
+if [[ $1 = lucky ]]; then
+	eix-update
+	eix --stable --only-names | grep -E -v '^(acct|virtual|sec)-' | sort -u > /tmp/stable
+	eix --installed --only-names | sort -u > /tmp/installed
+	comm -23 /tmp/stable /tmp/installed > /tmp/uninstalled-stable
+	sed -i 's/--binpkg-respect-use//' /etc/portage/make.conf
+
+	to_install=(--autounmask --autounmask-keep-keywords --autounmask-write --autounmask-continue $(shuf -n1 /tmp/uninstalled-stable))
+elif [[ $1 ]]; then
+	pushd /etc/portage/variants/$1
+	while read -r -d '' line; do
+		dest=../../${line%.footer}
+		if [[ ${line} = world* ]]; then
+			dest=/var/lib/portage/world
+		fi
+
+		if [[ ${line} = world.remove ]]; then
+			emerge -C $(<"${line}")
+		elif [[ ${line} = *.footer ]]; then
+			cat "${line}" >> "${dest}"
+		else
+			cp "${line}" "${dest}"
+		fi
+	done < <(find . -type f -printf '%P\0')
+	if [[ -f buildpkgonly ]]; then
+		./buildpkgonly
+	fi
+	popd
+fi
+
+emerge -uDNkq --changed-deps --backtrack=100 --keep-going "${to_install[@]}"
+
+if [[ ! $1 ]]; then
+	emerge --depclean --quiet-unmerge-warn
+fi