Find systemd units on disk and report the packages the desktop needs

docs/install.md

@@ -30,7 +30,10 @@ with `--check`.
    than assuming step 1 ran.
 3. **Packages** come from `packages/blob.packages` and
    `packages/blob-aur.packages`. A machine with no AUR helper gets `yay-bin`
-   built once with `makepkg`. See [packages.md](packages.md).
+   built once with `makepkg`. A failed batch refreshes the databases and retries,
+   then falls back to one package at a time, so a single name that no longer
+   resolves cannot cost you the other hundred and the config, service and login
+   steps below. See [packages.md](packages.md).
 4. **Config** is copied into `~/.config`: `hypr/`, the themed app configs,
    `blob/shell.json`, the uwsm environment, and the icon font.
    `session/profile.sh` also goes to `/etc/profile.d/blob.sh`, which sources
@@ -63,7 +66,17 @@ with `--check`.
    avahi, docker, power-profiles-daemon, and oomd.
    `NetworkManager-wait-online.service` is masked so a slow DHCP lease cannot
    hold up the login screen.
-9. **The login screen** is SDDM. Three pieces have to be in place:
+9. **The login screen** is SDDM. It has to be installed first: if
+   `sddm.service` is not there, the installer says whether the package is
+   missing or whether systemd has simply not re-read its units yet, and carries
+   on without enabling anything. A unit counts as present when `systemctl cat`
+   finds it or when its file is under `/etc/systemd/system`,
+   `/run/systemd/system`, `/usr/local/lib/systemd/system` or
+   `/usr/lib/systemd/system` - `systemctl` goes through the service manager, so
+   it reports a perfectly good unit as missing inside a chroot or right after
+   pacman wrote it.
+
+   Three pieces have to be in place:
 
    | File | Why |
    | --- | --- |
@@ -97,10 +110,13 @@ with `--check`.
 
    `--autologin` writes `zzz-blob-autologin.conf`, the only file that sorts after
    `zz-blob.conf`.
-10. **Launch.** When the installer was run from a console and nothing graphical
-    is running, it starts `sddm.service` so the desktop appears without a reboot.
-    `--no-launch` prints the command instead. `--autologin` writes
-    `/etc/sddm.conf.d/zzz-blob-autologin.conf` for the current user.
+10. **Launch.** `sddm`, `hyprland`, `quickshell` and `uwsm` are checked one last
+    time and any that are missing are named, because that is the whole difference
+    between a desktop and a console. Then, when the installer was run from a
+    console and nothing graphical is running, it starts `sddm.service` so the
+    desktop appears without a reboot. `--no-launch` prints the command instead.
+    `--autologin` writes `/etc/sddm.conf.d/zzz-blob-autologin.conf` for the
+    current user.
 
 ## Flags
 

docs/packages.md

@@ -81,6 +81,14 @@ packages pulled in under a different name no longer come back on every run. AUR
 packages are built one at a time, so a build that fails is reported at the end
 instead of stopping the install.
 
+Repo packages go in one `pacman` call. If that call fails the databases are
+refreshed with `pacman -Sy` and it is tried again, because a stale database is
+what turns an installed-and-present package into `target not found`. If it still
+fails the packages are installed one at a time, so one unresolvable name does not
+block the other hundred - which is how a missing `sddm` used to turn into a
+machine with no login screen. `install.sh` ends by naming any of `sddm`,
+`hyprland`, `quickshell` and `uwsm` that are still not installed.
+
 `./install.sh --check` lists what it would install without installing anything,
 and `--skip-packages` does the directories and config only.
 

install.sh

@@ -82,6 +82,7 @@ install_session_entry
 install_autologin
 enable_display_manager
 report_login_conflicts
+report_desktop_essentials
 
 say ""
 if [[ $check == true ]]; then

install/helpers/lib.sh

@@ -8,8 +8,23 @@ note_change() {
   changes=$((changes + 1))
 }
 
+unit_search_dirs=(
+  /etc/systemd/system
+  /run/systemd/system
+  /usr/local/lib/systemd/system
+  /usr/lib/systemd/system
+)
+
 system_unit_exists() {
-  systemctl cat -- "$1" &>/dev/null
+  local unit="$1" dir
+
+  systemctl cat -- "$unit" &>/dev/null && return 0
+
+  for dir in "${unit_search_dirs[@]}"; do
+    [[ -e $dir/$unit ]] && return 0
+  done
+
+  return 1
 }
 
 user_manager_available() {

install/steps/login.sh

@@ -85,7 +85,13 @@ report_login_conflicts() {
 # its default target is multi-user.target, which never pulls in graphical.target.
 enable_display_manager() {
   if ! system_unit_exists sddm.service; then
-    say "WARN  sddm.service not found; the desktop cannot start at boot"
+    if package_installed sddm; then
+      say "WARN  sddm is installed but sddm.service is not visible to systemd"
+      say "      run 'sudo systemctl daemon-reload', then ./install.sh again"
+    else
+      say "WARN  sddm is not installed; the desktop cannot start at boot"
+      say "      install it with 'sudo pacman -S sddm', then ./install.sh again"
+    fi
     return 0
   fi
 
@@ -114,13 +120,19 @@ enable_display_manager() {
   fi
 
   if [[ $enable_needed == true ]]; then
-    as_root systemctl enable sddm.service
+    if as_root systemctl enable sddm.service; then
       say "enable sddm.service"
+    else
+      say "WARN  could not enable sddm.service"
+    fi
   fi
 
   if [[ $target_needed == true ]]; then
-    as_root systemctl set-default graphical.target
+    if as_root systemctl set-default graphical.target; then
       say "set   default target to graphical.target"
+    else
+      say "WARN  could not set the default target to graphical.target"
+    fi
   fi
 }
 
@@ -137,6 +149,7 @@ launch_desktop() {
   fi
 
   if ! system_unit_exists sddm.service; then
+    say "No login screen to start: sddm is not installed."
     return 0
   fi
 
@@ -151,5 +164,7 @@ launch_desktop() {
   fi
 
   say "Starting the login screen. Pick the Blob session to log in."
-  as_root systemctl start sddm.service
+  as_root systemctl start sddm.service || {
+    say "WARN  sddm.service did not start; see 'systemctl status sddm'"
+  }
 }

install/steps/packages.sh

@@ -58,7 +58,7 @@ install_packages() {
 
   if (( ${#repo_missing[@]} )); then
     say "install ${#repo_missing[@]} repo package(s)"
-    as_root pacman -S --needed --noconfirm "${repo_missing[@]}"
+    install_repo_packages "${repo_missing[@]}"
   fi
 
   if (( ${#aur_missing[@]} )); then
@@ -71,6 +71,45 @@ install_packages() {
   fi
 }
 
+install_repo_packages() {
+  local package
+  local -a failed=()
+
+  as_root pacman -S --needed --noconfirm "$@" && return 0
+
+  say "WARN  the batch install failed; refreshing the package databases"
+  as_root pacman -Sy --noconfirm || true
+  as_root pacman -S --needed --noconfirm "$@" && return 0
+
+  say "WARN  still failing; retrying one package at a time"
+  for package in "$@"; do
+    as_root pacman -S --needed --noconfirm "$package" || failed+=("$package")
+  done
+
+  (( ${#failed[@]} == 0 )) && return 0
+
+  say "WARN  ${#failed[@]} repo package(s) failed to install: ${failed[*]}"
+}
+
+desktop_essentials=(sddm hyprland quickshell uwsm)
+
+report_desktop_essentials() {
+  local package
+  local -a missing=()
+
+  for package in "${desktop_essentials[@]}"; do
+    package_installed "$package" || missing+=("$package")
+  done
+
+  if (( ${#missing[@]} == 0 )); then
+    say "ok    desktop essentials"
+    return 0
+  fi
+
+  say "WARN  the desktop cannot start without: ${missing[*]}"
+  say "      install them with 'sudo pacman -S ${missing[*]}', then ./install.sh again"
+}
+
 install_aur_packages() {
   local package
   local -a failed=()