[Bug 2144691] [NEW] dirmngr 2.4.8-2ubuntu2.1 preinst script corrupted (syntax error at line 472 in dpkg-maintscript-helper) blocks install/upgrade in Ubuntu 25.10

[tstrike]

Public bug reported:

Title
dirmngr 2.4.8-2ubuntu2.1 preinst script corrupted (syntax error at line 472 in dpkg-maintscript-helper) blocks install/upgrade in Ubuntu 25.10
Description
Affects: Ubuntu 25.10 (Questing Quokka)
Package: dirmngr (source: gnupg2)
Version: 2.4.8-2ubuntu2.1 (from questing-updates/main)
Architecture: amd64
Symptom
Any attempt to install, upgrade, or fix dirmngr fails with the same error during unpack:
text/usr/bin/dpkg-maintscript-helper: 472: Syntax error: end of file unexpected (expecting "}")
dpkg: error processing archive .../dirmngr_2.4.8-2ubuntu2.1_amd64.deb (--unpack):
 new dirmngr package pre-installation script subprocess returned error exit status 2
This also affects post-removal and post-install scripts in cleanup. The same pattern has appeared in dependent packages (gnupg2, gpg-wks-client) and has spread to others (openssh-client, openssh-server, login, libreoffice-common) during troubleshooting.
Steps to Reproduce

Fresh or partially broken Ubuntu 25.10 install
sudo apt update && sudo apt install dirmngr
Observe failure during the unpacking of the dirmngr deb.

Expected
Package installs/upgrades without script errors.
Actual
Preinst script fails with a syntax error. Error is consistent across mirrors (us.archive.ubuntu.com, security.ubuntu.com, archive.ubuntu.com).
Workarounds Attempted (all temporary)

Rename/remove corrupt prerm/postinst → create dummy empty scripts → force-purge with --force-all
Manual deb extraction (dpkg -x) → copy files to /usr/ → ldconfig
Fake status in /var/lib/dpkg/info/dirmngr.list with Status: install ok configured
apt-mark hold dirmngr to prevent future upgrades
Purge dependent packages (gnupg2, gpg-wks-client) to stop demand

None permanently stops the loop when apt re-downloads the deb (e.g., during fix-broken, upgrade, or reinstall).
Additional Notes

The deb file itself appears corrupted (consistent failure across mirrors).
Manual extraction works — files function normally (dirmngr --version returns 2.4.8).
The issue affects the dependency chain (gnupg2 → dirmngr, etc.) and blocks normal upgrade/autoremove.

Please investigate the build/upload process for gnupg2 2.4.8-2ubuntu2.1
in questing-updates. This may affect other packages if maintscripts are
broken in the pipeline.

** Affects: dpkg (Ubuntu)
     Importance: Undecided
         Status: New

** Affects: gnupg2 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: dirmngrpreinstcorrupted-script25.10questing

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https://bugs.launchpad.net/bugs/2144691

Title:
  dirmngr 2.4.8-2ubuntu2.1 preinst script corrupted (syntax error at
  line 472 in dpkg-maintscript-helper) blocks install/upgrade in Ubuntu
  25.10

Status in dpkg package in Ubuntu:
  New
Status in gnupg2 package in Ubuntu:
  New

Bug description:
  Title
  dirmngr 2.4.8-2ubuntu2.1 preinst script corrupted (syntax error at line 472 in dpkg-maintscript-helper) blocks install/upgrade in Ubuntu 25.10
  Description
  Affects: Ubuntu 25.10 (Questing Quokka)
  Package: dirmngr (source: gnupg2)
  Version: 2.4.8-2ubuntu2.1 (from questing-updates/main)
  Architecture: amd64
  Symptom
  Any attempt to install, upgrade, or fix dirmngr fails with the same error during unpack:
  text/usr/bin/dpkg-maintscript-helper: 472: Syntax error: end of file unexpected (expecting "}")
  dpkg: error processing archive .../dirmngr_2.4.8-2ubuntu2.1_amd64.deb (--unpack):
   new dirmngr package pre-installation script subprocess returned error exit status 2
  This also affects post-removal and post-install scripts in cleanup. The same pattern has appeared in dependent packages (gnupg2, gpg-wks-client) and has spread to others (openssh-client, openssh-server, login, libreoffice-common) during troubleshooting.
  Steps to Reproduce

  Fresh or partially broken Ubuntu 25.10 install
  sudo apt update && sudo apt install dirmngr
  Observe failure during the unpacking of the dirmngr deb.

  Expected
  Package installs/upgrades without script errors.
  Actual
  Preinst script fails with a syntax error. Error is consistent across mirrors (us.archive.ubuntu.com, security.ubuntu.com, archive.ubuntu.com).
  Workarounds Attempted (all temporary)

  Rename/remove corrupt prerm/postinst → create dummy empty scripts → force-purge with --force-all
  Manual deb extraction (dpkg -x) → copy files to /usr/ → ldconfig
  Fake status in /var/lib/dpkg/info/dirmngr.list with Status: install ok configured
  apt-mark hold dirmngr to prevent future upgrades
  Purge dependent packages (gnupg2, gpg-wks-client) to stop demand

  None permanently stops the loop when apt re-downloads the deb (e.g., during fix-broken, upgrade, or reinstall).
  Additional Notes

  The deb file itself appears corrupted (consistent failure across mirrors).
  Manual extraction works — files function normally (dirmngr --version returns 2.4.8).
  The issue affects the dependency chain (gnupg2 → dirmngr, etc.) and blocks normal upgrade/autoremove.

  Please investigate the build/upload process for gnupg2
  2.4.8-2ubuntu2.1 in questing-updates. This may affect other packages
  if maintscripts are broken in the pipeline.

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