package firebird3.0-server 3.0.2.32703.ds4-9 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[ShidaBR]

Package update fails.
Post-installation script exits with error if:
 - user exists (old reports of this bug)
 - user is not a system user (new reports of this bug).

ProblemType: Package
DistroRelease: Ubuntu 17.10
Package: firebird3.0-server 3.0.2.32703.ds4-9
ProcVersionSignature: Ubuntu 4.13.0-38.43-generic 4.13.16
Uname: Linux 4.13.0-38-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.8
Architecture: amd64
Date: Thu Apr 12 14:43:15 2018
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2018-04-12 (1 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20180105.1)
Python3Details: /usr/bin/python3.6, Python 3.6.3, python3-minimal, 3.6.3-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.14, python-minimal, 2.7.14-2ubuntu1
RelatedPackageVersions:
 dpkg 1.18.24ubuntu1
 apt 1.5.1
SourcePackage: firebird3.0
Title: package firebird3.0-server 3.0.2.32703.ds4-9 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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

[Natalia Sorokina (sonaux)]

postinstall script /var/lib/dpkg/info/firebird3.0-server.postinst exits with error after command:
`adduser --system --quiet --home /var/lib/firebird --group --gecos "Firebird Database Administator" firebird`
when user 'firebird' exists or/and it is not system user.

Following patch should fix this bug (script will check if firebird user exists before trying to add it):

diff firebird3.0-server.postinst.orig firebird3.0-server.postinst
34,35c34,38
< adduser --system --quiet --home /var/lib/firebird \
< --group --gecos "Firebird Database Administator" firebird
---
> if ! getent passwd firebird >/dev/null; then
> adduser --system --quiet --home /var/lib/firebird \
> --group --gecos "Firebird Database Administator" firebird
> fi
>

[Natalia Sorokina (sonaux)]

Another way: ignore errors.

     if ! getent passwd firebird >/dev/null; then
         adduser --system --quiet --home /var/lib/firebird \
             --group --gecos "Firebird Database Administator" firebird
     fi

[Natalia Sorokina (sonaux)]

...oops, wrong button :)

    set +e
    adduser --system --quiet --home /var/lib/firebird \
        --group --gecos "Firebird Database Administator" firebird
    set -e

That way adduser will report about errors, but script will not fail.