[Bug 2125393] [NEW] release upgrade 24.10 -> 25.04 fails: AttributeError: 'ExplodedDeb822SourceEntry' object has no attribute 'section'

[Pasu Boonvisut]

Public bug reported:

Problem Description

When attempting to upgrade a system from Ubuntu 24.10 to the development
release of Ubuntu 25.04 using sudo do-release-upgrade, the process
fails. The upgrader crashes with a Python AttributeError after fetching
the new upgrade tool.

The traceback indicates the error occurs in the _addSecuritySources
method within DistUpgradeController.py, when the script attempts to
access a .section attribute on an ExplodedDeb822SourceEntry object,
which does not exist. This prevents the upgrade from starting.

Steps to Reproduce

    On a fully updated Ubuntu 24.10 system, open a terminal.

    Run the command: sudo do-release-upgrade

    Observe the tool as it begins to run and subsequently crashes.

Expected Results

The release upgrader should successfully prepare the system for the
upgrade, rewrite the package source lists, and begin the process of
downloading and installing the new packages for Ubuntu 25.04.

Actual Results

The upgrade process terminates prematurely and prints the following
Python traceback to the console:

Traceback (most recent call last):
  File "/tmp/ubuntu-release-upgrader-essb9mo7/plucky", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeMain.py", line 235, in main
    if app.run():
       ^^^^^^^^^
  File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 1965, in run
    return self.fullUpgrade()
           ^^^^^^^^^^^^^^^^^^
  File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 1793, in fullUpgrade
    if not self.updateDeb822Sources():
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 978, in updateDeb822Sources
    if not self.rewriteDeb822Sources():
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 966, in rewriteDeb822Sources
    self._addSecuritySources()
  File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 761, in _addSecuritySources
    e.section['Signed-By'] = '/usr/share/keyrings/ubuntu-archive-keyring.gpg'
    ^^^^^^^^^
AttributeError: 'ExplodedDeb822SourceEntry' object has no attribute 'section'

Additional Information

Attempting to run the upgrade non-interactively produces the same
AttributeError.

Command:
sudo do-release-upgrade -f DistUpgradeViewNonInteractive

Output:

Checking for a new Ubuntu release
Your Ubuntu release is not supported anymore.
For upgrade information, please visit:
http://www.ubuntu.com/releaseendoflife

Get:1 Upgrade tool signature [833 B]                                    
Get:2 Upgrade tool [965 kB]                                              
Fetched 966 kB in 0s (0 B/s)                                              
/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcherCore.py:237: Warning: W:Download is performed unsandboxed as root as file 'plucky.tar.gz.gpg' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)

** Affects: ubuntu-release-upgrader (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 dist-upgrade oracular plucky

** Tags added: dist-upgrade

** Tags added: amd64 oracular plucky

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https://bugs.launchpad.net/bugs/2125393

Title:
  release upgrade 24.10 -> 25.04 fails: AttributeError:
  'ExplodedDeb822SourceEntry' object has no attribute 'section'

Status in ubuntu-release-upgrader package in Ubuntu:
  New

Bug description:
  Problem Description

  When attempting to upgrade a system from Ubuntu 24.10 to the
  development release of Ubuntu 25.04 using sudo do-release-upgrade, the
  process fails. The upgrader crashes with a Python AttributeError after
  fetching the new upgrade tool.

  The traceback indicates the error occurs in the _addSecuritySources
  method within DistUpgradeController.py, when the script attempts to
  access a .section attribute on an ExplodedDeb822SourceEntry object,
  which does not exist. This prevents the upgrade from starting.

  Steps to Reproduce

      On a fully updated Ubuntu 24.10 system, open a terminal.

      Run the command: sudo do-release-upgrade

      Observe the tool as it begins to run and subsequently crashes.

  Expected Results

  The release upgrader should successfully prepare the system for the
  upgrade, rewrite the package source lists, and begin the process of
  downloading and installing the new packages for Ubuntu 25.04.

  Actual Results

  The upgrade process terminates prematurely and prints the following
  Python traceback to the console:

  Traceback (most recent call last):
    File "/tmp/ubuntu-release-upgrader-essb9mo7/plucky", line 8, in <module>
      sys.exit(main())
               ^^^^^^
    File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeMain.py", line 235, in main
      if app.run():
         ^^^^^^^^^
    File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 1965, in run
      return self.fullUpgrade()
             ^^^^^^^^^^^^^^^^^^
    File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 1793, in fullUpgrade
      if not self.updateDeb822Sources():
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 978, in updateDeb822Sources
      if not self.rewriteDeb822Sources():
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 966, in rewriteDeb822Sources
      self._addSecuritySources()
    File "/tmp/ubuntu-release-upgrader-essb9mo7/DistUpgrade/DistUpgradeController.py", line 761, in _addSecuritySources
      e.section['Signed-By'] = '/usr/share/keyrings/ubuntu-archive-keyring.gpg'
      ^^^^^^^^^
  AttributeError: 'ExplodedDeb822SourceEntry' object has no attribute 'section'

  Additional Information

  Attempting to run the upgrade non-interactively produces the same
  AttributeError.

  Command:
  sudo do-release-upgrade -f DistUpgradeViewNonInteractive

  Output:

  Checking for a new Ubuntu release
  Your Ubuntu release is not supported anymore.
  For upgrade information, please visit:
  http://www.ubuntu.com/releaseendoflife

  Get:1 Upgrade tool signature [833 B]                                    
  Get:2 Upgrade tool [965 kB]                                              
  Fetched 966 kB in 0s (0 B/s)                                              
  /usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcherCore.py:237: Warning: W:Download is performed unsandboxed as root as file 'plucky.tar.gz.gpg' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)

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