G_AG_CHECK_INSTALL_PREREQ does not work in some cases

[Sympatron]

Creating a bug report/issue

• [x] I have searched the existing open and closed issues

Required Information

• DietPi version | cat /boot/dietpi/.version

G_DIETPI_VERSION_CORE=8
G_DIETPI_VERSION_SUB=1
G_DIETPI_VERSION_RC=2
G_GITBRANCH='master'
G_GITOWNER='MichaIng'
G_LIVE_PATCH_STATUS[0]='applied'
G_LIVE_PATCH_STATUS[1]='applied'
G_LIVE_PATCH_STATUS[2]='not applicable'
G_LIVE_PATCH_STATUS[3]='not applicable'

• Distro version | echo $G_DISTRO_NAME $G_RASPBIAN
  • bullseye 0
• Kernel version | uname -a
  • Linux LidarTestPi 5.10.92-v8+ #1514 SMP PREEMPT Mon Jan 17 17:39:38 GMT 2022 aarch64 GNU/Linux
• SBC model | echo $G_HW_MODEL_NAME or (EG: RPi3)
  • RPi 4 Model B (aarch64)
• Power supply used | (EG: 5V 1A RAVpower)
  • 5V 2A
• SD card used | (EG: SanDisk ultra)

Additional Information (if applicable)

• Software title | (EG: Nextcloud)
  • sytemd-timesyncd
• Was the software title installed freshly or updated/migrated?
• Can this issue be replicated on a fresh installation of DietPi?
  • Maybe
• Bug report ID | echo $G_HW_UUID

Steps to reproduce

I don't know how sytemd-timesyncd got into this state, but on my machine running dpkg-query -s systemd-timesyncd (which is what is used by G_AG_CHECK_INSTALL_PREREQ) returns (with exit code 0):

Package: systemd-timesyncd
Status: deinstall ok config-files
Priority: optional
Section: admin
Installed-Size: 197
Maintainer: Debian systemd Maintainers <[email protected]>
Architecture: arm64
Multi-Arch: foreign
Source: systemd
Version: 247.3-6
Config-Version: 247.3-6
Replaces: systemd (<< 245.4-2~), time-daemon
Provides: time-daemon
Depends: libc6 (>= 2.29), systemd (= 247.3-6), adduser
Breaks: systemd (<< 245.4-2~)
Conflicts: time-daemon
Conffiles:
 /etc/dhcp/dhclient-exit-hooks.d/timesyncd c66e563f4050725592e2da20a4e1bfef
 /etc/systemd/timesyncd.conf e563c788b019216ec2ad3a43bf89e315
Description: minimalistic service to synchronize local time with NTP servers
 The package contains the systemd-timesyncd system service that may be used to
 synchronize the local system clock with a remote Network Time Protocol server.
Homepage: https://www.freedesktop.org/wiki/Software/systemd

Because it exists with exit code 0, G_AG_CHECK_INSTALL_PREREQ will not install the package. This was discovered, because setting time synchronization to "daemon + drift" in dietpi-config did not work properly.

Expected behaviour

G_AG_CHECK_INSTALL_PREREQ should only skip installation if it is actually fully installed.

Actual behaviour

G_AG_CHECK_INSTALL_PREREQ skips installation if the package status is "deinstall ok config-files". This may be true for other status values as well.

Extra details

I know I am using an old version of DietPi, but the source code that triggers this behaviour is still the same: My version: https://github.com/MichaIng/DietPi/blob/fb8d2dd08bcae898ec8e8846554244f667480f67/dietpi/func/dietpi-globals#L1677 Current master: https://github.com/MichaIng/DietPi/blob/4471bf892e57845714b820f4f0df238f8a8f4392/dietpi/func/dietpi-globals#L1723

[MichaIng]

Thanks for your report. That is true, if the package has been removed, but not purged, and config files were left in place. One solution would be dpkg-query -s "$i" | grep -q '^Status: install ok installed$', but I'll check whether there is a dpkg-query-internal filter which allows to skip the additional pipe.

This affects a lot of other places in DietPi code. It rarely plays a role, since at least we consequently purge packages internally as long as they are not reinstalled afterwards within the same script/run, and many packages we check this way, like kernel packages, do not have config files. But makes sense to make this check failsafe in all cases.