Ensure GDM sees managed users after reboot

debian/authd.service.in

@@ -3,6 +3,8 @@ Description=authd daemon service
 After=authd.socket
 Requires=authd.socket
 PartOf=authd.socket
+# AccountsService starts after this target to populate the GDM user list.
+Before=nss-user-lookup.target
 
 [Service]
 Type=notify

debian/authd.socket

@@ -6,6 +6,8 @@ Wants=dbus.service
 After=dbus.service
 Before=nss-user-lookup.target
 Wants=nss-user-lookup.target
+# Start the daemon before AccountsService queries NSS for its cached users.
+Wants=authd.service
 
 [Socket]
 ListenStream=/run/authd.sock

e2e-tests/resources/utils.resource

@@ -83,6 +83,11 @@ Wait Until GDM Login Screen Ready
     BuiltIn.Sleep    2
 
 
+Wait Until System Is Running Or Degraded
+    Wait Until Keyword Succeeds    3 min    1 sec
+    ...    SSH.Execute    output=$(systemctl is-system-running --wait) || [ "$output" = degraded ]
+
+
 Wait Until Desktop Ready
     Wait Until Keyword Succeeds    1 min    1 sec
     ...    Try Desktop Ready

e2e-tests/tests/gdm_managed_user_after_reboot.robot

@@ -0,0 +1,29 @@
+*** Settings ***
+Resource        resources/utils.resource
+Resource        resources/authd.resource
+Resource        resources/broker.resource
+
+Test Setup       utils.Test Setup    snapshot=%{BROKER}-installed
+Test Teardown    utils.Test Teardown
+
+
+*** Variables ***
+${username}        %{E2E_USER}
+${local_password}  qwer1234
+
+
+*** Test Cases ***
+Managed user is listed by GDM after reboot
+    [Documentation]    Verify that GDM discovers an existing managed user during boot.
+    ...
+    ...                Do not query NSS after the reboot: that would activate authd and
+    ...                hide the startup-ordering regression this test covers.
+    Log In With Remote User Through GDM: QR Code    ${username}    ${local_password}
+    Log Out
+    ${display_name} =    SSH.Execute    getent passwd ${username} | cut -d: -f5 | cut -d, -f1
+
+    Run Keyword And Ignore Error    SSH.Execute    systemctl reboot
+    Wait Until System Is Running Or Degraded
+
+    Wait Until GDM Login Screen Ready
+    Match Text    ${display_name}    30

e2e-tests/vm/lib/libprovision.sh

@@ -62,10 +62,16 @@ function force_create_snapshot() {
 
     if virsh domstate "${VM_NAME}" | grep -q '^running'; then
         # If the VM is running, we have to use --memspec to create the snapshot
-        local memfile="${IMAGE%.qcow2}-${snapshot_name}.mem"
+        # Libvirt's default disk filename is derived from the snapshot name.
+        # A failed or metadata-only-deleted snapshot can leave that file behind.
+        local snapshot_id
+        snapshot_id="$(date +%s%N)"
+        local diskfile="${IMAGE%.qcow2}.${snapshot_name}.${snapshot_id}"
+        local memfile="${IMAGE%.qcow2}-${snapshot_name}.${snapshot_id}.mem"
         time virsh snapshot-create-as \
           --domain "${VM_NAME}" \
           --name "${snapshot_name}" \
+          --diskspec "vda,file=${diskfile},snapshot=external" \
           --memspec "${memfile},snapshot=external"
         return
     fi