[Bug 2096824] Re: apport_excepthook called with incorrect number of arguments

[Nick Rosbrook]

This needs more work for jammy->noble upgrades. After fixing the call to
apport_excepthook, importing apport fails with the following message in
/var/log/dist-upgrade/main.log:

ERROR: failed to import apport python module, can't generate crash: No
module named 'pickle'

This apparently has to do with the fact that python3 is upgraded during
this whole process. But, if the apport import is moved earlier (i.e. not
on-demand when the crash occurs), apport later complains that
/usr/bin/python3.10 (i.e. the old version in this case) is gone.

Hence, I am going to skip this bug for the noble SRU for now.

** Description changed:

  [Impact]
  
  Bugs about the upgrade process might not be reported because the apport
  hook is not working correctly. This was caused by apport chaning the
  signature of apport_excepthook().
  
  [Test Plan]
  
  We need to force and exception to occur and observe that apport handles
  it correctly. Because the function signature changed between jammy and
  noble, the test plan is slightly different depending on the upgrade
  path. In either case, we interrupt the upgrade after the script is
  downloaded, and modify DistUpgradeController.py to unconditionally raise
  an exception at a given point.
  
  1. Start an upgrade:
  
  $ do-release-upgrade --proposed
  
  Accept the initial prompt, but then decline the next one (before the
  upgrade really begins).
  
  2. Navigate to the temp directory where the upgrade script was unpacked:
  
  $ cd "$(find /tmp/ -name ubuntu-release-upgrader-* -type d)"
  
  3. Edit the DistUpgradeController.py script to contain a line with:
  
  raise Exception("Test 123")
  
  For oracular, add this at the end of the __init__() function. For noble,
  add this at the end of fullUpgrade().
  
  4. Run the upgrade, and observe that the exception is caught, and the
  apport hook is called as a result:
  
  $ ./oracular
  
  OR
  
  $ ./noble
  
  [Where problems could occur]
  
  Any further issues would be related to the apport hook, because we are
  chaning the number of arguments passed.
  
- For jammy->noble, this risk is mitigated by trying the old way, catching
- TypeError, and then trying the new way. This is necessary because the
- change happened between jammy and noble.
- 
- For noble->oracular, the apport function has the same signature, so this
- extra step is not necessary.
- 
  [Original Description]
  
  When there was a failure to handle an upgrade, apport_crash() gets
  called to handle it and it calls apport_excepthook(), but it is missing
  an argument in that call:
  
  Error in sys.excepthook:
  Traceback (most recent call last):
    File "/tmp/ubuntu-release-upgrader-rj__cqhy/DistUpgrade/DistUpgradeViewText.py", line 138, in _handleException
      apport_crash(type, value, tb)
    File "/tmp/ubuntu-release-upgrader-rj__cqhy/DistUpgrade/DistUpgradeApport.py", line 57, in apport_crash
      apport_excepthook(type, value, tb)
  TypeError: apport_excepthook() missing 1 required positional argument: 'exc_tb'
  
  In my case, that was because I had Apt::Default-Release "noble"; in my
  apt.conf. That issue is on me and I've fixed that misconfiguration.
  However, this bug is about the second exception that was triggered when
  trying to handle the first exception. It seems that apport_excepthook is
  missing the binary argument. Maybe apport_crash() needs to be passing in
  sys.argv[0] in DistUpgradeApport.py on it's call to
  apport_excepthook()??
  
  This crash can also be seen in another, recent bug report:
  
  https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-
  upgrader/+bug/2064955

** Changed in: ubuntu-release-upgrader (Ubuntu Noble)
       Status: Triaged => Incomplete

** Also affects: apport (Ubuntu)
   Importance: Undecided
       Status: New

** Changed in: apport (Ubuntu)
       Status: New => Invalid

** Changed in: apport (Ubuntu Oracular)
       Status: New => Invalid

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https://bugs.launchpad.net/bugs/2096824

Title:
  apport_excepthook called with incorrect number of arguments

Status in apport package in Ubuntu:
  Invalid
Status in ubuntu-release-upgrader package in Ubuntu:
  Fix Released
Status in apport source package in Noble:
  New
Status in ubuntu-release-upgrader source package in Noble:
  Incomplete
Status in apport source package in Oracular:
  Invalid
Status in ubuntu-release-upgrader source package in Oracular:
  Triaged

Bug description:
  [Impact]

  Bugs about the upgrade process might not be reported because the
  apport hook is not working correctly. This was caused by apport
  chaning the signature of apport_excepthook().

  [Test Plan]

  We need to force and exception to occur and observe that apport
  handles it correctly. Because the function signature changed between
  jammy and noble, the test plan is slightly different depending on the
  upgrade path. In either case, we interrupt the upgrade after the
  script is downloaded, and modify DistUpgradeController.py to
  unconditionally raise an exception at a given point.

  1. Start an upgrade:

  $ do-release-upgrade --proposed

  Accept the initial prompt, but then decline the next one (before the
  upgrade really begins).

  2. Navigate to the temp directory where the upgrade script was
  unpacked:

  $ cd "$(find /tmp/ -name ubuntu-release-upgrader-* -type d)"

  3. Edit the DistUpgradeController.py script to contain a line with:

  raise Exception("Test 123")

  For oracular, add this at the end of the __init__() function. For
  noble, add this at the end of fullUpgrade().

  4. Run the upgrade, and observe that the exception is caught, and the
  apport hook is called as a result:

  $ ./oracular

  OR

  $ ./noble

  [Where problems could occur]

  Any further issues would be related to the apport hook, because we are
  chaning the number of arguments passed.

  [Original Description]

  When there was a failure to handle an upgrade, apport_crash() gets
  called to handle it and it calls apport_excepthook(), but it is
  missing an argument in that call:

  Error in sys.excepthook:
  Traceback (most recent call last):
    File "/tmp/ubuntu-release-upgrader-rj__cqhy/DistUpgrade/DistUpgradeViewText.py", line 138, in _handleException
      apport_crash(type, value, tb)
    File "/tmp/ubuntu-release-upgrader-rj__cqhy/DistUpgrade/DistUpgradeApport.py", line 57, in apport_crash
      apport_excepthook(type, value, tb)
  TypeError: apport_excepthook() missing 1 required positional argument: 'exc_tb'

  In my case, that was because I had Apt::Default-Release "noble"; in my
  apt.conf. That issue is on me and I've fixed that misconfiguration.
  However, this bug is about the second exception that was triggered
  when trying to handle the first exception. It seems that
  apport_excepthook is missing the binary argument. Maybe apport_crash()
  needs to be passing in sys.argv[0] in DistUpgradeApport.py on it's
  call to apport_excepthook()??

  This crash can also be seen in another, recent bug report:

  https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-
  upgrader/+bug/2064955

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