[Bug 1551929] Re: Cannot upgrade to 15.10 using alternate AMD64 ISO

[dino99]

** Changed in: ubuntu-release-upgrader (Ubuntu Wily)
       Status: Triaged => Invalid

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to ubuntu-release-upgrader in
Ubuntu.
https://bugs.launchpad.net/bugs/1551929

Title:
  Cannot upgrade to 15.10 using alternate AMD64 ISO

Status in ubuntu-release-upgrader package in Ubuntu:
  Fix Released
Status in ubuntu-release-upgrader source package in Wily:
  Invalid

Bug description:
  # lsb_release -rd
  Description:    Ubuntu 15.10
  Release:        15.10

  # apt-cache policy python3-distupgrade
  python3-distupgrade:
    Installed: 1:15.10.14.4
    Candidate: 1:15.10.14.4
    Version table:
   *** 1:15.10.14.4 0
          500 http://ca.archive.ubuntu.com/ubuntu/ wily-updates/main amd64 Packages
          100 /var/lib/dpkg/status
       1:15.10.13 0
          500 http://ca.archive.ubuntu.com/ubuntu/ wily/main amd64 Packages

  
  I am a Lubuntu AMD64 user. I was on Lubuntu 14.10 and needed to upgrade. After successfully upgrading to vivid/15.04, I then tried to upgrade to wily/15.10. In both cases, I used the alternate ISO.

  First, I downloaded the ISO file and mounted it to my local file
  system:

  # sudo mount -o loop ~/Desktop/x220/lubuntu-15.10-alternate-amd64.iso
  /mnt

  Second, I executed the upgrade script and chose the 'no network'
  option:

  # sudo /mnt/cdromupgrade

  But it failed early in the sequence of events. The relevant part of
  the /var/log/dist-upgrade/main.log file showed the following:

  2016-02-28 12:19:17,788 ERROR not handled exception:
  Traceback (most recent call last):

    File "/tmp/tmp.vQLpNb1AlJ/wily", line 8, in <module>
      sys.exit(main())

    File "/tmp/tmp.vQLpNb1AlJ/DistUpgrade/DistUpgradeMain.py", line 240, in main
      if app.run():

    File "/tmp/tmp.vQLpNb1AlJ/DistUpgrade/DistUpgradeController.py", line 1837, in run
      return self.fullUpgrade()

    File "/tmp/tmp.vQLpNb1AlJ/DistUpgrade/DistUpgradeController.py", line 1729, in fullUpgrade
      not self.aptcdrom.add(self.sources_backup_ext)):

    File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeAptCdrom.py", line 306, in add
      res = self._doAdd()

    File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeAptCdrom.py", line 264, in _doAdd
      if self._verifyRelease(self.signatures):

    File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeAptCdrom.py", line 227, in _verifyRelease
      sum = apt_pkg.sha256sum(open(fp))

  TypeError: invalid file: <_io.TextIOWrapper
  name='/mnt/dists/wily/restricted/debian-installer/binary-
  amd64/Packages.gz' mode='r' encoding='UTF-8'>

  After some detective work, I was able to upgrade to wily by removing
  the 'open' call in line 227:

      sum = apt_pkg.sha256sum(fp)

  An important step in the detective work was to inspect the changes to the DistUpgradeAptCdrom.py file
  (http://bazaar.launchpad.net/~ubuntu-core-dev/ubuntu-release-upgrader/trunk/revision/2859#tests/test_sources_list.py).
  There, we can see that the line:

  sum = apt_pkg.sha256sum(open(f))

  was changed to:

  with open(f) as fp:
      sum = apt_pkg.sha256sum(open(fp))

  The end result is that a call to open() was changed to use a with/as
  statement, as part of a substantial commit to improve the robustness
  of the code. But for this line, it introduced two open calls instead
  of just one, and that is clearly wrong, as the first open call will
  return a File object, and the second will try to open the consequent
  File object, which will result in a Type error.

  Revision 2859 was done about a year ago, and refers to LP #1409555,
  which seems to indicate that the fix was added in 15.04. It explains
  why I was able to upgrade to 15.04 but not to 15.10.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1551929/+subscriptions