"No valid sources.list entry found" during attempt to upgrade from Eoan to Focal

[Norbert]

Steps to reproduce:
1. Have Ubuntu 19.10 installed (edition really does not matter, but tested on MATE)
2. Run `update-manager -d -c `
3. Follow wizard, confirm upgrade to 20.04 LTS

Expected results:
* upgrade is started and ended successfully

Actual results:
* upgrade is not started, have the following window

```
No valid sources.list entry found

While scanning your repository information no entry about disco could be found.

An upgrade might not succeed.

Do you want to continue anyway?

No Yes
```

Terminal output is the following:

```
$ update-manager -d -c
WARNING:root:can not import unity GI Namespace Dbusmenu not available
Checking for a new Ubuntu release
Checking for a new Ubuntu release
/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcher.py:23: PyGIWarning: Gtk was imported without specifying a version first. Use gi.require_version('Gtk', '3.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gtk, Gdk
/usr/lib/python3/dist-packages/DistUpgrade/ReleaseNotesViewerWebkit.py:33: PyGIWarning: WebKit2 was imported without specifying a version first. Use gi.require_version('WebKit2', '4.0') before import to ensure that the right version gets loaded.
  from gi.repository import WebKit2 as WebKit
error: XDG_RUNTIME_DIR not set in the environment.
authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
extracting 'focal.tar.gz'

```

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: ubuntu-release-upgrader-core 1:19.10.15
ProcVersionSignature: Ubuntu 5.3.0-19.20-generic 5.3.1
Uname: Linux 5.3.0-19-generic x86_64
ApportVersion: 2.20.11-0ubuntu8.1
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: MATE
Date: Sat Nov 2 16:51:48 2019
InstallationDate: Installed on 2019-10-19 (14 days ago)
InstallationMedia: Ubuntu-MATE 19.10 "Eoan Ermine" - Release amd64 (20191017)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: ubuntu-release-upgrader
UpgradeStatus: Upgraded to eoan on 2019-11-02 (0 days ago)
VarLogDistupgradeAptlog:
 Log time: 2019-11-02 16:49:52.579694
 Log time: 2019-11-02 16:49:56.716523
VarLogDistupgradeTermlog:

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1851040

[Norbert (nrbrtx)]

Upgrade from fails too:

```
$ sudo do-release-upgrade -d
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [1 554 B]
Get:2 Upgrade tool [1 334 kB]
45% [2 606 kB/1 334 kB 45%] Fetched 1 335 kB in 0s (0 B/s)
authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
extracting 'focal.tar.gz'

Reading cache

Checking package manager
Reading package lists... Done
Building dependency tree
Reading state information... Done
Hit http://archive.ubuntu.com/ubuntu eoan InRelease
Get:1 http://security.ubuntu.com/ubuntu eoan-security InRelease [92,9 kB]
Hit http://archive.ubuntu.com/ubuntu eoan-updates InRelease
Hit http://archive.ubuntu.com/ubuntu eoan-backports InRelease
Fetched 92,9 kB in 0s (0 B/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done

Updating repository information

No valid sources.list entry found

While scanning your repository information no entry about disco could
be found.

An upgrade might not succeed.

Do you want to continue anyway?

Continue [yN]

Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done
```

[Norbert (nrbrtx)]

The problem persists if we use Eoan mini.iso ( http://archive.ubuntu.com/ubuntu/dists/eoan/main/installer-amd64/current/images/netboot/mini.iso ) as starting point.

[Chippo Elder (chiphog)]

@Norbert: You're pretty keen! The rest of us 'round here, are struggling to get TO eoan, while you're struggling to LEAVE it! :-) Good for you.

But you will understand if your bugs are de-prioritized, until some earlier bugs are resolved...

[Derk Willem te Bokkel (dtebokkel)]

appears to be using eoan package sources for focal upgrade..

first check normal state of apt update to eoan for reference:

derk@zlink1 ~ $ sudo apt update
Hit:1 http://ca.archive.ubuntu.com/ubuntu eoan InRelease
Hit:2 http://ca.archive.ubuntu.com/ubuntu eoan-updates InRelease
Hit:3 http://ca.archive.ubuntu.com/ubuntu eoan-backports InRelease
Hit:4 http://ca.archive.ubuntu.com/ubuntu eoan-security InRelease
Hit:5 http://ca.archive.ubuntu.com/ubuntu eoan-proposed InRelease
Reading package lists... Done
Building dependency tree
Reading state information... Done
All packages are up to date.

### okay now try upgrade:

RC=0 derk@zlink1 ~ $ sudo do-release-upgrade -d
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [1,554 B]
Get:2 Upgrade tool [1,334 kB]
Fetched 1,335 kB in 0s (0 B/s)
authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
extracting 'focal.tar.gz'

Reading cache

Checking package manager
Reading package lists... Done
Building dependency tree
Reading state information... Done
Hit http://ca.archive.ubuntu.com/ubuntu eoan InRelease
Hit http://ca.archive.ubuntu.com/ubuntu eoan-updates InRelease
Hit http://ca.archive.ubuntu.com/ubuntu eoan-backports InRelease
Hit http://ca.archive.ubuntu.com/ubuntu eoan-security InRelease
Hit http://ca.archive.ubuntu.com/ubuntu eoan-proposed InRelease
Fetched 0 B in 0s (0 B/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done

Updating repository information

No valid sources.list entry found

While scanning your repository information no entry about disco could
be found.

An upgrade might not succeed.

Do you want to continue anyway?
                             ### Uhmm this should be focal not eoan here no-wonder we fails
Continue [yN] y
Hit http://ca.archive.ubuntu.com/ubuntu eoan InRelease
Hit http://ca.archive.ubuntu.com/ubuntu eoan-updates InRelease
Hit http://ca.archive.ubuntu.com/ubuntu eoan-backports InRelease
Hit http://ca.archive.ubuntu.com/ubuntu eoan-security InRelease
Hit http://ca.archive.ubuntu.com/ubuntu eoan-proposed InRelease
Fetched 0 B in 0s (0 B/s)

Checking package manager
Reading package lists... Done
Building dependency tree
Reading state information... Done

Calculating the changes

Calculating the changes

Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done

#### so the upgrade file has been accidentally reverted to eoan ??

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Derk Willem te Bokkel (dtebokkel)]

In fact in comment #7 the first package list after opening focal.tar.gz should be based on focal as well ..

so the focal.tar.gz appears to be a renamed eoan.tar.gz not the true focal upgrade core.. !!!

what happened!!! .. I know the mirrors were messed-up nov 1-nov2 ..

did other files get renamed and shuffled by accident or malice??

[Stephen Michael Kellat (skellat)]

Confirmed the bug while trying to upgrade a DigitalOcean VM from eoan to focal.

[Derk Willem te Bokkel (dtebokkel)]

A work around exists .. at the pause .. do you want to continue? in another terminal manually edit /etc/apt/sources.list to change all eoan to focal ..save then press y to proceed and everything proceeds normally ..

my comment #9 was incorrect the first list shown is eoan then the sources are swapped / over written or sed edited by the script or rather should be.

[Brian Murray (brian-murray)]

This change will have fixed it.

  [ Brian Murray ]
  * data/DistUpgrade.cfg, data/DistUpgrade.cfg.bionic: update for the upgrade
    from 19.10 to 20.04 harder.