do-release-upgrade crashes in Greek locale

Bug #1572416 reported by Alkis Georgopoulos on 2016-04-20
This bug affects 1 person
Affects Status Importance Assigned to Milestone
ubuntu-release-upgrader (Ubuntu)
Steve Langasek
Steve Langasek
Steve Langasek

Bug Description

[SRU Justification]
Wrong translations and wrong behavior of upgrader

[Regression potential]
Code changes are specific to an input function used at one specific point in the upgrader and should be very testable.

[Test case]
1. On Ubuntu 14.04, get a root shell in a terminal.
2. Run 'apt install language-pack-el'
3. Run 'LANG=el_GR.UTF-8 do-release-upgrade -d'
4. Confirm that the upgrader is shown in Greek.
5. When prompted whether or not to upgrade, confirm that the Continue prompt shows 'Συνἑχεια [yN]' instead of the expected 'Συνἑχεια [νΟ]'.
6. Type 'y<enter>' and see that the input is ignored and the prompt redisplayed.
7. Hit '<enter>' and see that the input is ignored and the prompt redisplayed.
8. Type (or cut and paste) 'ν<backspace><enter>' and confirm that the upgrader crashes.
9. Reset the environment by running sudo mv /etc/apt/sources.list.distUpgrade /etc/apt/sources.list
10. Run 'LANG=el_GR.UTF-8 do-release-upgrade -p'
11. Confirm that the upgrader is shown in Greek.
12. When prompted whether or not to upgrade, confirm that the Continue prompt shows 'Συνἑχεια [νΟ]'.
13. Type (or cut and paste) 'ν<backspace><enter>' and confirm that the upgrade cancels cleanly.
14. Run 'LANG=el_GR.UTF-8 do-release-upgrade -p' again.
15. Confirm that the upgrader is shown in Greek.
16. Type (or cut and paste) 'ν<enter>' and confirm that the upgrade proceeds.

I tried `do-release-upgrade -d` on an up to date 14.04 system, with Greek locale=el_GR.UTF-8.

I got notified that some packages are no longer supported by Canonical, and then I got this prompt:
Continue [yN] λεπτομέρειες [λ]

λεπτομέρειες means details.

I tried pressing [λ] and I got the (hopefully attached) crash. If it's not attached, I also uploaded it to

Then it restarted the upgrade process and it got to the same prompt. At that point, [λ] worked and showed me the no-longer supported packages,
but y/n didn't work at all, so I couldn't continue.

I pressed Ctrl+C to abort the upgrade process,
but now `do-release-upgrade -d` tells me there's no new distribution available to upgrade to, possibly because it's checking my just-broken sources.list...

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.8
ProcVersionSignature: Ubuntu 3.13.0-85.129-generic 3.13.11-ckt36
Uname: Linux 3.13.0-85-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CrashDB: ubuntu
Date: Wed Apr 20 08:52:43 2016
InstallationDate: Installed on 2015-01-29 (446 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64+mac (20140722.2)
PackageArchitecture: all
 PATH=(custom, no user)
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2016-04-20 (0 days ago)

Related branches

Alkis Georgopoulos (alkisg) wrote :
Alkis Georgopoulos (alkisg) wrote :

On the fourth try, I did manage to get it to continue by pressing "ν", which is the Greek letter for "y", Yes.

"ο" which is the Greek letter for "N", No, also worked.

So to sum up the bugs I saw:
1) [Enter] should work and select the default choice when the prompt is "[yN]". It didn't; it prompt me again.

a) The code is wrong, it should support both the English letters (y/n) and the localized ones (ν/ο).
b) OR, the translation is wrong and it shouldn't list the English letters.

3) Ctrl+C didn't revert my sources.list.

4) The initial crash while pressing "λ".

Brian Murray (brian-murray) wrote :

The logs indicate that the text view was being used:

2016-04-20 08:38:55,901 DEBUG Using 'DistUpgradeViewText' view

Looking at the translations for el we can see that 'y' and 'n' are not translated.

1594 #: ../DistUpgrade/
1595 #: ../DistUpgrade/
1596 #: ../DistUpgrade/
1597 msgid "Continue [yN] "
1598 msgstr "Συνέχεια [yN] "

1644 #: ../DistUpgrade/
1645 msgid "Continue [Yn] "
1646 msgstr "Συνέχεια [Yn] "

So that answers part 2 at least.

Changed in ubuntu-release-upgrader (Ubuntu):
importance: Undecided → High
Steve Langasek (vorlon) wrote :

The backtrace shows:
 UnicodeDecodeError: 'utf-8' codec can't decode byte 0xcf in position 0: invalid continuation byte

You state in your bug report that your locale is set to el_GR.UTF-8; so 'utf-8' codec should be correct and your input should be in utf-8 encoding.

Confusingly, I can't see why your input would *include* the listed 0xcf byte. The UTF-8 encoding of λ is 0xce 0xb4.

If this problem is reproducible, please do:

  echo -n <text_to_paste_into_prompt> | od -tx1

Attach the result of this command to this bug.

Then, instead of typing the answer into the do-release-upgrade terminal, please cut and paste the text there and verify that the backtrace is still reproducible.

Alkis Georgopoulos (alkisg) wrote :

Unfortunately, since I upgraded that PC to 16.04, I cannot use do-release-upgrade anymore to reproduce anything related to this bug report.

If (4) is not reproducible by anyone else, maybe addressing (1), (2) and (3) will be enough...

Steve Langasek (vorlon) wrote :

I can confirm 2, and this is a bug in the translation. Fixed in bzr.

I can also confirm 1, from the source. Also fixed in bzr.

3, I'm not surprised if that's an issue. I doubt we have a very robust signal handler in place. This seems unrelated to the main topic of the bug report, however; feel free to file a new one.

Still looking at trying to reproduce 4. But this may come down to a bit flip error on your system, because I can't think of any other way that a 'λ' keypress would generate 0xcf instead of 0xce.

Steve Langasek (vorlon) on 2016-04-21
Changed in ubuntu-release-upgrader (Ubuntu):
status: New → In Progress
Steve Langasek (vorlon) on 2016-04-21
Changed in ubuntu-release-upgrader (Ubuntu Xenial):
assignee: nobody → Steve Langasek (vorlon)
Steve Langasek (vorlon) on 2016-04-21
description: updated
Steve Langasek (vorlon) on 2016-04-21
description: updated
Steve Langasek (vorlon) wrote :

And the failure for 4 is reproducible if you use the backspace key on the input; since we're not using a real readline library that counts characters, a backspace will delete the character on the screen but leave part of the bytes in the input buffer.

Hello Alkis, or anyone else affected,

Accepted ubuntu-release-upgrader into xenial-proposed. The package will build now and be available at in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at . Thank you in advance!

Changed in ubuntu-release-upgrader (Ubuntu Xenial):
status: In Progress → Fix Committed
tags: added: verification-needed
Alkis Georgopoulos (alkisg) wrote :

Hi adconrad,

1) I can't test the proposed do-release-upgrade because I've already upgraded.

2) Even if I find another 14.04 system to test with, I'd need the package to be in trusty-proposed, not in xenial-proposed, right?
Or should I directly download the .deb? Will the python dependencies etc be compatible in that case?

Steve Langasek (vorlon) on 2016-04-25
description: updated
Steve Langasek (vorlon) on 2016-04-25
description: updated
Brian Murray (brian-murray) wrote :

The release upgrade process downloads a tarball from the release to which you are upgrading and uses the code in that tarball. Subsequently, the fix only needs to appear in the destination release.

Steve Langasek (vorlon) wrote :

The launchpad translation importer messed me up on this last upload, and we wound up reverting the translation fixes I had committed. So another upload will be needed.

I also think, from local testing, that the use of the built-in input() is not a 100% fix for the backspace problem, though it may give some improvement.

tags: added: verification-failed
removed: verification-needed
Steve Langasek (vorlon) on 2016-04-26
Changed in ubuntu-release-upgrader (Ubuntu Xenial):
status: Fix Committed → In Progress
Brian Murray (brian-murray) wrote :

There is a new version of the release upgrader in proposed now that should fix this.

tags: added: verification-needed
removed: verification-failed
Steve Langasek (vorlon) on 2016-04-26
description: updated
Barry Warsaw (barry) wrote :

Tried in both Trusty (where python3 == python3.4) and Xenial (where python3 == python3.5) chroots, with -updates enabled and thus the latest python3.x's available, using the reproducer in the bug description. I get no crashes or bogus output. Pasting Greek input, hitting backspace (test: one, several, none) just results in the Greek prompt being redisplayed.

We'll call this verification-done!

tags: added: verification-done
removed: verification-needed
Adam Conrad (adconrad) on 2016-04-28
Changed in ubuntu-release-upgrader (Ubuntu Xenial):
status: In Progress → Fix Released
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package ubuntu-release-upgrader - 1:16.10.1

ubuntu-release-upgrader (1:16.10.1) yakkety; urgency=medium

  * DistUpgrade/{EOL,}ReleaseAnnouncement,
    - updated for 16.04 -> 16.10
  * tests/ modify how the LANG environment variable was
    being modified there by fixing a test failure in

 -- Brian Murray <email address hidden> Tue, 03 May 2016 08:54:38 -0700

Changed in ubuntu-release-upgrader (Ubuntu Yakkety):
status: Fix Committed → Fix Released
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