[Bug 1970761] Re: Upgrades to 22.04 can cause netplan failures on Raspi

[Dave Jones]

** Merge proposal linked:
   https://code.launchpad.net/~jawn-smith/ubuntu/+source/ubuntu-release-upgrader/+git/ubuntu-release-upgrader/+merge/421557

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https://bugs.launchpad.net/bugs/1970761

Title:
  Upgrades to 22.04 can cause netplan failures on Raspi

Status in ubuntu-release-upgrader package in Ubuntu:
  Confirmed
Status in ubuntu-release-upgrader source package in Jammy:
  Confirmed

Bug description:
  [Impact]
      * In Jammy, Netplan commands fail if the following
        lines are present in the netplan config file:
        ```
        match:
           driver: bcmgenet smsc95xx lan78xx
        ```
      * Those lines are present in the default netplan config
        for Raspberry Pis in focal, hirsute, and impish
      * As a result, upgrades to jammy from older releases
        lead to netplan failures and broken networking

  [Test Plan]
      * Install impish on a Raspberry Pi
      * Upgrade to jammy using `do-release-upgrade -d`
      * Run `sudo netplan apply` and observe the command
        fails and the networking does not work
      * Reinstall impish on the Raspberry Pi
      * Upgrade to jammy using `do-release upgrade -d` with
        the proposed pocket enabled
      * Run `sudo netplan apply` and observe that the
        command succeeds and networking is functional

  [Regression Potential]
      * Since ubuntu-release-upgrader is modifying
        netplan's config, it is possible that custom
        configs could be impacted where not intended.

  [Original Description]
  The default netplan yaml configuration file on Raspi for older releases is

  ```
  network:
      ethernets:
          eth0:
              dhcp4: true
              match:
                  driver: bcmgenet smsc95xx lan78xx
              optional: true
              set-name: eth0
      version: 2
  ```

  In the version of netplan in jammy, the match section is no longer
  needed and causes netplan failures due to incompatible formatting. A
  quirk should be made to remove the match section.

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