test: add coverage for multi-unit transactions

Co-developed-by: Claude Opus 4.7 <noreply@anthropic.com>

diff --git a/test/units/TEST-07-PID1.multi-units-transaction.sh b/test/units/TEST-07-PID1.multi-units-transaction.sh
new file mode 100755 (executable)
index 0000000..d8bf794
--- /dev/null
+++ b/test/units/TEST-07-PID1.multi-units-transaction.sh
@@ -0,0 +1,375 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+set -eux
+set -o pipefail
+
+# Operate multiple units in a single transaction.
+# Issue: https://github.com/systemd/systemd/issues/8102
+#
+# When 'systemctl start <a> <b>' is executed, both units must be enqueued in a
+# single transaction so that After= ordering is honoured regardless of the order
+# of the arguments. Previously each unit was sent to PID1 in its own D-Bus
+# request and thus its own transaction, which meant the ordering dependency was
+# only effective when the dependee was queued before the dependent.
+
+MARKER_DIR="$(mktemp -d /tmp/issue8102.marker.XXXXXX)"
+MARKER="$MARKER_DIR/done"
+SOCK_DIR="$(mktemp -d /tmp/issue8102.sock.XXXXXX)"
+SOCK_PATH="$SOCK_DIR/sock"
+
+at_exit() {
+    set +e
+
+    systemctl stop issue8102-second.service issue8102-first.service
+    systemctl stop issue8102-sock-foo.service issue8102-sock-foo.socket
+    systemctl stop 'issue8102-many@*.service'
+    systemctl stop issue8102-conflict-a.service issue8102-conflict-b.service
+    systemctl reset-failed issue8102-second.service issue8102-first.service
+    systemctl reset-failed issue8102-sock-foo.service issue8102-sock-foo.socket
+    systemctl reset-failed 'issue8102-many@*.service'
+    systemctl reset-failed issue8102-conflict-a.service issue8102-conflict-b.service
+    rm -f /run/systemd/system/issue8102-{first,second}.service
+    rm -f /run/systemd/system/issue8102-sock-foo.{service,socket}
+    rm -f /run/systemd/system/issue8102-many@.service
+    rm -f /run/systemd/system/issue8102-conflict-{a,b}.service
+    rm -rf "$MARKER_DIR" "$SOCK_DIR"
+    systemctl daemon-reload
+}
+
+trap at_exit EXIT
+
+mkdir -p /run/systemd/system
+
+cat >/run/systemd/system/issue8102-first.service <<EOF
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/bin/sh -c 'sleep 1 && echo done > "$MARKER"'
+EOF
+
+cat >/run/systemd/system/issue8102-second.service <<EOF
+[Unit]
+After=issue8102-first.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/bin/sh -c 'test -e "$MARKER"'
+EOF
+
+systemctl daemon-reload
+rm -f "$MARKER"
+
+# Pass the units in reverse dependency order. Without the single-transaction
+# fix, second.service is enqueued first, dispatched immediately (because
+# first.service has no pending job at that point) and fails because the marker
+# does not yet exist. With the fix the units are submitted to PID1 in a single
+# request and After= ordering is honoured.
+systemctl start issue8102-second.service issue8102-first.service
+
+test -e "$MARKER"
+[[ "$(systemctl show -P ActiveState issue8102-first.service)" == active ]]
+[[ "$(systemctl show -P ActiveState issue8102-second.service)" == active ]]
+
+# Same exercise via the new D-Bus method, calling it directly via busctl. This
+# verifies the EnqueueUnitJobMany() method is implemented and behaves as expected.
+systemctl stop issue8102-second.service issue8102-first.service
+rm -f "$MARKER"
+
+busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    2 issue8102-second.service issue8102-first.service \
+    start replace \
+    0
+
+# Wait for both units to settle.
+# shellcheck disable=SC2016
+timeout 30s bash -c '
+    while [[ "$(systemctl show -P ActiveState issue8102-first.service)" != active ]] ||
+          [[ "$(systemctl show -P ActiveState issue8102-second.service)" != active ]]; do
+        sleep 0.5
+    done
+'
+
+test -e "$MARKER"
+
+# Second scenario: a service unit ordered after its socket unit, passed to
+# 'systemctl start' with the service first and the socket second. With per-unit
+# transactions the service is enqueued alone: After= alone does not pull in the
+# socket, so the service runs before the socket has been listening and its
+# ExecStart fails. With a single transaction the After= ordering between the
+# two anchors is honored, the socket is brought up first and the service
+# succeeds.
+
+cat >/run/systemd/system/issue8102-sock-foo.socket <<EOF
+[Socket]
+ListenStream=$SOCK_PATH
+EOF
+
+cat >/run/systemd/system/issue8102-sock-foo.service <<EOF
+[Unit]
+After=issue8102-sock-foo.socket
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/bin/sh -c 'test -S "$SOCK_PATH"'
+EOF
+
+systemctl daemon-reload
+
+systemctl start issue8102-sock-foo.service issue8102-sock-foo.socket
+
+[[ "$(systemctl show -P ActiveState issue8102-sock-foo.service)" == active ]]
+[[ "$(systemctl show -P ActiveState issue8102-sock-foo.socket)" == active ]]
+test -S "$SOCK_PATH"
+
+# Third scenario: verify that EnqueueUnitJobMany supports the "reload-or-restart"
+# magic job type. The socket unit cannot reload, so it should get a restart job,
+# while the service unit (with Type=oneshot) also gets a restart. After the
+# call both units must be active again.
+busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    2 issue8102-sock-foo.service issue8102-sock-foo.socket \
+    reload-or-restart replace \
+    0 >/dev/null
+# Wait for the units to come back up after the restart.
+# shellcheck disable=SC2016
+timeout 30s bash -c '
+    while [[ "$(systemctl show -P ActiveState issue8102-sock-foo.service)" != active ]] ||
+          [[ "$(systemctl show -P ActiveState issue8102-sock-foo.socket)" != active ]]; do
+        sleep 0.5
+    done
+'
+test -S "$SOCK_PATH"
+
+# ---------------------------------------------------------------------------
+# Argument validation corner cases for EnqueueUnitJobMany().
+# ---------------------------------------------------------------------------
+
+# Empty units array → the handler must reject the call with an INVALID_ARGS
+# error before doing anything.
+out=$(busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    0 \
+    start replace \
+    0 2>&1) && { echo 'busctl unexpectedly succeeded'; exit 1; }
+echo "$out" | grep -F "No units specified" >/dev/null
+
+# Non-zero flags parameter is reserved and must be rejected.
+out=$(busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    1 issue8102-first.service \
+    start replace \
+    1 2>&1) && { echo 'busctl unexpectedly succeeded'; exit 1; }
+echo "$out" | grep -F "Invalid flags parameter" >/dev/null
+
+# Bogus job type → rejected before any job is constructed.
+out=$(busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    1 issue8102-first.service \
+    not-a-real-job-type replace \
+    0 2>&1) && { echo 'busctl unexpectedly succeeded'; exit 1; }
+echo "$out" | grep -F "Job type not-a-real-job-type invalid" >/dev/null
+
+# Bogus job mode → rejected before any job is constructed.
+out=$(busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    1 issue8102-first.service \
+    start not-a-real-mode \
+    0 2>&1) && { echo 'busctl unexpectedly succeeded'; exit 1; }
+echo "$out" | grep -F "Job mode not-a-real-mode invalid" >/dev/null
+
+# Unknown unit must be reported as an error and no partial state should remain
+# in the job queue: list one valid + one bogus unit, ensure the call fails and
+# that the valid unit has no pending start job afterwards.
+systemctl stop issue8102-first.service
+[[ "$(systemctl show -P ActiveState issue8102-first.service)" == inactive ]]
+
+(! busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    2 issue8102-first.service issue8102-does-not-exist.service \
+    start replace \
+    0 2>/dev/null)
+
+# busctl is synchronous: by the time the call returns with an error, PID1 has
+# already rejected the transaction. Verify the valid unit was not started
+# behind our back (the transaction must be all-or-nothing).
+[[ "$(systemctl show -P ActiveState issue8102-first.service)" == inactive ]]
+
+# ---------------------------------------------------------------------------
+# Many units in a single transaction.
+# ---------------------------------------------------------------------------
+# Build a template unit and instantiate a fair number of instances, all
+# enqueued via a single EnqueueUnitJobMany() call to exercise the strv path with
+# a transaction that anchors many units at once.
+
+cat >/run/systemd/system/issue8102-many@.service <<'EOF'
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/bin/true
+EOF
+systemctl daemon-reload
+
+MANY_COUNT=20
+mapfile -t MANY_UNITS < <(for i in $(seq 1 "$MANY_COUNT"); do printf 'issue8102-many@%d.service\n' "$i"; done)
+MANY_BUSCTL_ARGS=("$MANY_COUNT" "${MANY_UNITS[@]}")
+
+busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    "${MANY_BUSCTL_ARGS[@]}" \
+    start replace \
+    0 >/dev/null
+
+# Wait for every instance to become active.
+# shellcheck disable=SC2016
+timeout 30s bash -c '
+    for u in "$@"; do
+        while [[ "$(systemctl show -P ActiveState "$u")" != active ]]; do
+            sleep 0.2
+        done
+    done
+' bash "${MANY_UNITS[@]}"
+
+# Stop them all in one transaction too, verifying the stop path scales as well.
+busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    "${MANY_BUSCTL_ARGS[@]}" \
+    stop replace \
+    0 >/dev/null
+
+# shellcheck disable=SC2016
+timeout 30s bash -c '
+    for u in "$@"; do
+        while [[ "$(systemctl show -P ActiveState "$u")" != inactive ]]; do
+            sleep 0.2
+        done
+    done
+' bash "${MANY_UNITS[@]}"
+
+# ---------------------------------------------------------------------------
+# Incompatible transaction: two units that Conflict= with each other cannot be
+# started together. Both start anchors would force the other unit to stop, so
+# the transaction is unsatisfiable regardless of the chosen job mode. The
+# handler must report an error and roll back, so that neither unit ends up
+# active.
+# ---------------------------------------------------------------------------
+
+cat >/run/systemd/system/issue8102-conflict-a.service <<EOF
+[Unit]
+Conflicts=issue8102-conflict-b.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/bin/true
+EOF
+
+cat >/run/systemd/system/issue8102-conflict-b.service <<EOF
+[Unit]
+Conflicts=issue8102-conflict-a.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/bin/true
+EOF
+systemctl daemon-reload
+
+(! busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    2 issue8102-conflict-a.service issue8102-conflict-b.service \
+    start fail \
+    0 2>/dev/null)
+
+# Atomicity: neither unit must end up activated by the failed call. busctl is
+# synchronous so by the time it returns PID1 has already rolled back.
+[[ "$(systemctl show -P ActiveState issue8102-conflict-a.service)" == inactive ]]
+[[ "$(systemctl show -P ActiveState issue8102-conflict-b.service)" == inactive ]]
+
+# ---------------------------------------------------------------------------
+# reload-or-try-restart with a mix of reloadable and non-reloadable units.
+# The socket cannot reload so it must be restarted, while a unit that does
+# implement reload would be reloaded. Both must be active afterwards.
+# ---------------------------------------------------------------------------
+
+systemctl start issue8102-sock-foo.service issue8102-sock-foo.socket
+[[ "$(systemctl show -P ActiveState issue8102-sock-foo.service)" == active ]]
+[[ "$(systemctl show -P ActiveState issue8102-sock-foo.socket)" == active ]]
+
+busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    2 issue8102-sock-foo.service issue8102-sock-foo.socket \
+    reload-or-try-restart replace \
+    0 >/dev/null
+
+# shellcheck disable=SC2016
+timeout 30s bash -c '
+    while [[ "$(systemctl show -P ActiveState issue8102-sock-foo.service)" != active ]] ||
+          [[ "$(systemctl show -P ActiveState issue8102-sock-foo.socket)" != active ]]; do
+        sleep 0.5
+    done
+'
+test -S "$SOCK_PATH"
+
+# try-restart on a unit that is not currently running must be a no-op (no error)
+# and must not start it.
+systemctl stop issue8102-first.service
+[[ "$(systemctl show -P ActiveState issue8102-first.service)" == inactive ]]
+
+busctl call \
+    org.freedesktop.systemd1 \
+    /org/freedesktop/systemd1 \
+    org.freedesktop.systemd1.Manager \
+    EnqueueUnitJobMany \
+    assst \
+    1 issue8102-first.service \
+    try-restart replace \
+    0 >/dev/null
+
+[[ "$(systemctl show -P ActiveState issue8102-first.service)" == inactive ]]