package plymouth-theme-ubuntu-text 0.9.2-3ubuntu13.5 failed to install/upgrade: subprocess installed post-installation script returned error exit status 127

[Giancarlo Capezzone]

Plymouth broken after upgrading signal-desktop.
- I will remove signal-desktop (as I suspect it to block the use of Signal an my Jolla1 Smartphone),
- But the broken Plymouth is now preventing the daily update of Ubuntu an my Laptop.

While regularly updating my 16.04 (nearly daily) as listed below, one combination of signal-desktop and plymouth seem not compatible.
I will try to go back to the state of 2018-07-19 by using thr CLI:
    done_on="So 22. Jul 17:16:44 CEST 2018" #
 reset_to=; sudo apt-btrfs-snapshot set-default @apt-snapshot-2018-07-19_09:28:40 # before the next Upgrade: signal-desktop:amd64 (1.14.1, 1.14.2)
Default changed to @apt-snapshot-2018-07-19_09:28:40, please reboot for changes to take effect.

I have:
lsb_release -rd #
Description: Ubuntu 16.04.5 LTS
Release: 16.04
and=; apt-cache policy signal-desktop plymouth-theme-ubuntu-text #
signal-desktop:
  Installiert: 1.14.4
  Installationskandidat: 1.14.4
  Versionstabelle:
 *** 1.14.4 500
        500 https://updates.signal.org/desktop/apt xenial/main amd64 Packages
        100 /var/lib/dpkg/status
plymouth-theme-ubuntu-text:
  Installiert: 0.9.2-3ubuntu13.5
  Installationskandidat: 0.9.2-3ubuntu13.5
  Versionstabelle:
 *** 0.9.2-3ubuntu13.5 500
        500 http://de.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     0.9.2-3ubuntu13 500
        500 http://de.archive.ubuntu.com/ubuntu xenial/main amd64 Packages

EXAMPLE FOR RESULTING PROBLEMS:

For automatic bug report I want to install whoopsie:

which ends by:
dpkg: Fehler beim Bearbeiten des Paketes plymouth-theme-ubuntu-text (--remove):
 Unterprozess installiertes post-removal-Skript gab den Fehlerwert 127 zurück
Fehler traten auf beim Bearbeiten von:
 plymouth-theme-ubuntu-text
E: Sub-process /usr/bin/dpkg returned an error code (1)
THE SAME WITH MORE DETAILS:

apt-get install whoopsie
Paketlisten werden gelesen... Fertig
Abhängigkeitsbaum wird aufgebaut.
Statusinformationen werden eingelesen.... Fertig
»whoopsie« ist bereits die neuste Version (0.2.52.5).
whoopsie wurde als manuell installiert festgelegt.
Die folgenden Pakete wurden automatisch installiert und werden nicht mehr benötigt:
  libllvm5.0 libllvm5.0:i386
Verwenden Sie »apt autoremove«, um sie zu entfernen.
Die folgenden Pakete werden ENTFERNT:
  plymouth-theme-ubuntu-text
0 aktualisiert, 0 neu installiert, 1 zu entfernen und 0 nicht aktualisiert.
1 nicht vollständig installiert oder entfernt.
Nach dieser Operation werden 53,2 kB Plattenplatz freigegeben.
Möchten Sie fortfahren? [J/n] y
Supported
Create a snapshot of '/tmp/apt-btrfs-snapshot-mp-nztwrfzo/@' in '/tmp/apt-btrfs-snapshot-mp-nztwrfzo/@apt-snapshot-2018-07-22_18:01:12'
(Lese Datenbank ... 355480 Dateien und Verzeichnisse sind derzeit installiert.)
Entfernen von plymouth-theme-ubuntu-text (0.9.2-3ubuntu13.5) ...
/usr/sbin/update-initramfs: 21: /etc/initramfs-tools/update-initramfs.conf: http://www.freedesktop.org/wiki/Software/Plymouth: not found
dpkg: Fehler beim Bearbeiten des Paketes plymouth-theme-ubuntu-text (--remove):
 Unterprozess installiertes post-removal-Skript gab den Fehlerwert 127 zurück
Fehler traten auf beim Bearbeiten von:
 plymouth-theme-ubuntu-text
E: Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: plymouth-theme-ubuntu-text 0.9.2-3ubuntu13.5
ProcVersionSignature: Ubuntu 4.4.0-130.156-generic 4.4.134
Uname: Linux 4.4.0-130-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.18
AptOrdering:
 base-files: Install
 base-files: Configure
 signal-desktop: Install
 signal-desktop: Configure
 NULL: ConfigurePending
Architecture: amd64
BootLog:
 lvmetad is not active yet, using direct activation during sysinit
   "disk/by-uuid/af72c276-7ba6-4e62-a4fa-50adfef56909": Invalid path for Logical Volume.
 Scanning for Btrfs filesystems
Date: Sun Jul 22 02:41:59 2018
DefaultPlymouth: /usr/share/plymouth/themes/ubuntu-logo/ubuntu-logo.plymouth
DuplicateSignature:
 package:plymouth-theme-ubuntu-text:0.9.2-3ubuntu13.5
 Processing triggers for plymouth-theme-ubuntu-text (0.9.2-3ubuntu13.5) ...
 /usr/sbin/update-initramfs: 21: /etc/initramfs-tools/update-initramfs.conf: http://www.freedesktop.org/wiki/Software/Plymouth: not found
 dpkg: error processing package plymouth-theme-ubuntu-text (--unpack):
  subprocess installed post-installation script returned error exit status 127
ErrorMessage: subprocess installed post-installation script returned error exit status 127
InstallationDate: Installed on 2016-12-15 (584 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: LENOVO 4276CTO
ProcCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-130-generic root=UUID=f452415b-5f76-4710-a884-8244e2260834 ro rootflags=subvol=@ cryptdevice=UUID=476a905e-8e64-4097-9ef6-c1e844ecb476:luks-476a905e-8e64-4097-9ef6-c1e844ecb476 kopt=root=/dev/mapper/luks-476a905e-8e64-4097-9ef6-c1e844ecb476 resume=UUID=af72c276-7ba6-4e62-a4fa-50adfef56909 rootflags=subvol=@ quiet splash vt.handoff=7
ProcFB:
 0 inteldrmfb
 1 nouveaufb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-130-generic root=UUID=f452415b-5f76-4710-a884-8244e2260834 ro rootflags=subvol=@ cryptdevice=UUID=476a905e-8e64-4097-9ef6-c1e844ecb476:luks-476a905e-8e64-4097-9ef6-c1e844ecb476 kopt=root=/dev/mapper/luks-476a905e-8e64-4097-9ef6-c1e844ecb476 resume=UUID=af72c276-7ba6-4e62-a4fa-50adfef56909 rootflags=subvol=@ quiet splash vt.handoff=7
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.4
 apt 1.2.27
SourcePackage: plymouth
TextPlymouth: Error: command ['readlink', '/etc/alternatives/text.plymouth'] failed with exit code 1:
Title: package plymouth-theme-ubuntu-text 0.9.2-3ubuntu13.5 failed to install/upgrade: subprocess installed post-installation script returned error exit status 127
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/02/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 8BET54WW (1.34 )
dmi.board.asset.tag: Not Available
dmi.board.name: 4276CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr8BET54WW(1.34):bd11/02/2011:svnLENOVO:pn4276CTO:pvrThinkPadW520:rvnLENOVO:rn4276CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 4276CTO
dmi.product.version: ThinkPad W520
dmi.sys.vendor: LENOVO

[Giancarlo Capezzone (giancarlo-capezzone)]

Now I could try to revert to a previous correct state+redo the Updates - through apt-btrfs-snapshot set-default <to-older-snapshot-presumably-correct>.

BUT, alas: the Error occurs AGAIN!

The Steps:
sudo apt-btrfs-snapshot set-default @apt-snapshot-2018-07-19_09:28:40
Default changed to @apt-snapshot-2018-07-19_09:28:40, please reboot for changes to take effect.

apt-get update #
OK:1 http://ppa.launchpad.net/alexlarsson/flatpak/ubuntu xenial InRelease
OK:2 http://de.archive.ubuntu.com/ubuntu xenial InRelease
OK:3 http://archive.canonical.com/ubuntu xenial InRelease
OK:4 http://security.ubuntu.com/ubuntu xenial-security InRelease
OK:5 http://de.archive.ubuntu.com/ubuntu xenial-updates InRelease
OK:6 http://ppa.launchpad.net/yannubuntu/boot-repair/ubuntu xenial InRelease
OK:7 http://de.archive.ubuntu.com/ubuntu xenial-backports InRelease
OK:8 https://updates.signal.org/desktop/apt xenial InRelease
OK:9 https://riot.im/packages/debian xenial InRelease
Paketlisten werden gelesen... Fertig
root@ubu476:~# time apt-get upgrade && echo ok | grep ok #
Paketlisten werden gelesen... Fertig
Abhängigkeitsbaum wird aufgebaut.
Statusinformationen werden eingelesen.... Fertig
Paketaktualisierung (Upgrade) wird berechnet... Fertig
Die folgenden Pakete wurden automatisch installiert und werden nicht mehr benötigt:
  libllvm5.0 libllvm5.0:i386
Verwenden Sie »apt autoremove«, um sie zu entfernen.
Die folgenden Pakete werden aktualisiert (Upgrade):
  base-files python-apt python-apt-common python3-apt signal-desktop snapd ubuntu-core-launcher
7 aktualisiert, 0 neu installiert, 0 zu entfernen und 0 nicht aktualisiert.
Es müssen 80,2 MB an Archiven heruntergeladen werden.
Nach dieser Operation werden 1.219 kB Plattenplatz zusätzlich benutzt.
Möchten Sie fortfahren? [J/n] y
Holen:1 http://de.archive.ubuntu.com/ubuntu xenial-updates/main amd64 base-files amd64 9.4ubuntu4.7 [65,9 kB]
Holen:2 http://de.archive.ubuntu.com/ubuntu xenial-updates/main amd64 ubuntu-core-launcher amd64 2.33.1ubuntu2 [1.570 B]
Holen:3 http://de.archive.ubuntu.com/ubuntu xenial-updates/main amd64 snapd amd64 2.33.1ubuntu2 [14,1 MB]
Holen:4 https://updates.signal.org/desktop/apt xenial/main amd64 signal-desktop amd64 1.14.4 [65,7 MB]
Holen:5 http://de.archive.ubuntu.com/ubuntu xenial-updates/main amd64 python-apt-common all 1.1.0~beta1ubuntu0.16.04.2 [16,0 kB]
Holen:6 http://de.archive.ubuntu.com/ubuntu xenial-updates/main amd64 python3-apt amd64 1.1.0~beta1ubuntu0.16.04.2 [137 kB]
Holen:7 http://de.archive.ubuntu.com/ubuntu xenial-updates/main amd64 python-apt amd64 1.1.0~beta1ubuntu0.16.04.2 [139 kB]
55% [4 signal-desktop 23,6 MB/65,7 MB 36%] 1.217 kB/s 34 s
58% [4 signal-desktop 26,1 MB/65,7 MB 40%] ...

[Steve Langasek (vorlon)]

The error in your log is:

Processing triggers for plymouth-theme-ubuntu-text (0.9.2-3ubuntu13.5) ...
/usr/sbin/update-initramfs: 21: /etc/initramfs-tools/update-initramfs.conf: http://www.freedesktop.org/wiki/Software/Plymouth: not found
dpkg: error processing package plymouth-theme-ubuntu-text (--unpack):
 subprocess installed post-installation script returned error exit status 127

This indicates invalid syntax in /etc/initramfs-tools/update-initramfs.conf. I do not believe this is a bug in the plymouth package, which should never edit that config file on your system. I don't know why you have 'http://www.freedesktop.org/wiki/Software/Plymouth' written in this file, but it should be removed.

[Giancarlo Capezzone (giancarlo-capezzone)]

Full acknowledged.

(By the way, the string "http://www.freedesktop.org/wiki/Software/Plymouth" was appended to the end of /etc/initramfs-tools/update-initramfs.conf without ending CR/LF.)

I could not find out the origin of the change from my working notes.

The string appears first in a backup/snapshot on the 2018-02-28.
(latest="not found" on="2018-02-17". In-between I changed my backup technique, from rsync "snapshots" to btrfs snapshots+rsync.)

In the meantime reinstalling plymouth plus 2x kernel updates went through flawlessly.

Thanks for the prompt error analysis. Very well done!