[Bug 2141637] [NEW] ImportError: cannot import name 'inhibit_sleep' from 'DistUpgrade.utils' during 25.10 to 26.04 upgrade

[thomas moore]

Public bug reported:

While attempting an upgrade to the Ubuntu 26.04 "Resolute Raccoon"
development branch using do-release-upgrade -d, the process fails
immediately after downloading the upgrader tarball due to a Python
ImportError.

Steps to reproduce:

    Run sudo do-release-upgrade -d on an Ubuntu 25.10 system.
    The upgrader downloads the "resolute" tarball to /tmp.
    The process crashes before the UI initializes.

Expected Behavior:
The upgrader should initialize and begin the "Calculating Changes" phase.
Actual Behavior:
A Traceback occurs because DistUpgradeController.py attempts to import inhibit_sleep from DistUpgrade.utils, but that function is missing from the utils.py file in the current Resolute archive.

    Traceback (most recent call last):
  File "/tmp/ubuntu-release-upgrader-XXXXXX/resolute", line 8, in <module>
    sys.exit(main())
  File "/tmp/ubuntu-release-upgrader-XXXXXX/DistUpgrade/DistUpgradeMain.py", line 222, in main
    from .DistUpgradeController import DistUpgradeController
  File "/tmp/ubuntu-release-upgrader-XXXXXX/DistUpgrade/DistUpgradeController.py", line 43, in <module>
    from .utils import (..., inhibit_sleep)
ImportError: cannot import name 'inhibit_sleep' from 'DistUpgrade.utils'

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

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https://bugs.launchpad.net/bugs/2141637

Title:
  ImportError: cannot import name 'inhibit_sleep' from
  'DistUpgrade.utils' during 25.10 to 26.04 upgrade

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

Bug description:
  While attempting an upgrade to the Ubuntu 26.04 "Resolute Raccoon"
  development branch using do-release-upgrade -d, the process fails
  immediately after downloading the upgrader tarball due to a Python
  ImportError.

  Steps to reproduce:

      Run sudo do-release-upgrade -d on an Ubuntu 25.10 system.
      The upgrader downloads the "resolute" tarball to /tmp.
      The process crashes before the UI initializes.

  Expected Behavior:
  The upgrader should initialize and begin the "Calculating Changes" phase.
  Actual Behavior:
  A Traceback occurs because DistUpgradeController.py attempts to import inhibit_sleep from DistUpgrade.utils, but that function is missing from the utils.py file in the current Resolute archive.

      Traceback (most recent call last):
    File "/tmp/ubuntu-release-upgrader-XXXXXX/resolute", line 8, in <module>
      sys.exit(main())
    File "/tmp/ubuntu-release-upgrader-XXXXXX/DistUpgrade/DistUpgradeMain.py", line 222, in main
      from .DistUpgradeController import DistUpgradeController
    File "/tmp/ubuntu-release-upgrader-XXXXXX/DistUpgrade/DistUpgradeController.py", line 43, in <module>
      from .utils import (..., inhibit_sleep)
  ImportError: cannot import name 'inhibit_sleep' from 'DistUpgrade.utils'

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