[Bug 2143786] [NEW] release-upgrade-motd leaks stderr to terminal

[Andrey Filatov]

Public bug reported:

In /usr/lib/ubuntu-release-upgrader/release-upgrade-motd, the background
check-new-release process is started without redirecting stderr:

    /usr/lib/ubuntu-release-upgrader/check-new-release -q > "$stamp" &

When check-new-release fails to connect, the error appears in the
terminal:

    Failed to connect to https://changelogs.ubuntu.com/meta-release-lts.
    Check your Internet connection or proxy settings

This is unexpected — the process runs in the background (&) and uses
the -q (quiet) flag, so no output should be visible to the user.

Fix: redirect stderr to /dev/null for both occurrences:

    /usr/lib/ubuntu-release-upgrader/check-new-release -q > "$stamp"
2>/dev/null &

Package version: ubuntu-release-upgrader-core 1:24.04.28
Ubuntu version: 24.04.4 LTS (Noble)

Patch attached.

** Affects: ubuntu-release-upgrader (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: patch

** Patch added: "Fix: redirect stderr to /dev/null for background check-new-release calls"
   https://bugs.launchpad.net/bugs/2143786/+attachment/5951160/+files/fix-stderr-leak-in-release-upgrade-motd.patch

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https://bugs.launchpad.net/bugs/2143786

Title:
  release-upgrade-motd leaks stderr to terminal

Status in ubuntu-release-upgrader package in Ubuntu:
  New

Bug description:
  In /usr/lib/ubuntu-release-upgrader/release-upgrade-motd, the background
  check-new-release process is started without redirecting stderr:

      /usr/lib/ubuntu-release-upgrader/check-new-release -q > "$stamp" &

  When check-new-release fails to connect, the error appears in the
  terminal:

      Failed to connect to https://changelogs.ubuntu.com/meta-release-lts.
      Check your Internet connection or proxy settings

  This is unexpected — the process runs in the background (&) and uses
  the -q (quiet) flag, so no output should be visible to the user.

  Fix: redirect stderr to /dev/null for both occurrences:

      /usr/lib/ubuntu-release-upgrader/check-new-release -q > "$stamp"
  2>/dev/null &

  Package version: ubuntu-release-upgrader-core 1:24.04.28
  Ubuntu version: 24.04.4 LTS (Noble)

  Patch attached.

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