docker/podman-docker.sh breaks login shells

[Gchbg]

Issue Description

The latest Podman available in Debian trixie includes a script docker/podman-docker.sh which breaks login shells. This is because the script runs for all login shells and checks whether a variable is empty, but the variable may not even be set. This fails if a login shell runs with -eu (error checking and checking for undefined variables).

The fix is to replace the check on line 3 of the script. Instead of if [ -z "$DOCKER_HOST" ]; then, the line should be changed to if [ -z "${DOCKER_HOST-''}" ]; then. This will explicitly set the variable to the empty value if it is unset within the scope of the check.

$ podman version
Client:       Podman Engine
Version:      5.0.3
API Version:  5.0.3
Go Version:   go1.22.5
Built:        Thu Jan  1 02:00:00 1970
OS/Arch:      linux/amd64

Steps to reproduce the issue

Steps to reproduce the issue on a host system

1. Make sure DOCKER_HOST is not set
2. sudo su -l root -s /bin/sh -- -eu -c 'true' ; echo $?

Describe the results you received

$ sudo su -l root -s /bin/sh -- -eu -c 'true'; echo $?
-sh: 3: /etc/profile.d/podman-docker.sh: DOCKER_HOST: parameter not set
2

Describe the results you expected

$ sudo su -l root -s /bin/sh -- -eu -c 'true' ; echo $?
0

podman info output

host:
  arch: amd64
  buildahVersion: 1.35.3
  cgroupControllers:
  - cpu
  - memory
  - pids
  cgroupManager: systemd
  cgroupVersion: v2
  conmon:
    package: conmon_2.1.10+ds1-1+b1_amd64
    path: /usr/bin/conmon
    version: 'conmon version 2.1.10, commit: unknown'
  cpuUtilization:
    idlePercent: 99.3
    systemPercent: 0.11
    userPercent: 0.59
  cpus: 2
  databaseBackend: sqlite
  distribution:
    codename: trixie
    distribution: debian
    version: unknown
  eventLogger: journald
  freeLocks: 2048
  hostname: Farnsworth
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
    uidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
  kernel: 6.10.3-amd64
  linkmode: dynamic
  logDriver: journald
  memFree: 1634111488
  memTotal: 3387248640
  networkBackend: netavark
  networkBackendInfo:
    backend: netavark
    dns:
      package: aardvark-dns_1.9.0-2_amd64
      path: /usr/lib/podman/aardvark-dns
      version: aardvark-dns 1.9.0
    package: netavark_1.9.0-4_amd64
    path: /usr/lib/podman/netavark
    version: netavark 1.9.0
  ociRuntime:
    name: crun
    package: crun_1.15-1+b1_amd64
    path: /usr/bin/crun
    version: |-
      crun version 1.15
      commit: e6eacaf4034e84185fd8780ac9262bbf57082278
      rundir: /run/user/1000/crun
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +WASM:wasmedge +YAJL
  os: linux
  pasta:
    executable: /usr/bin/pasta
    package: passt_0.0~git20240806.ee36266-1_amd64
    version: |
      pasta 0.0~git20240806.ee36266-1
      Copyright Red Hat
      GNU General Public License, version 2 or later
        <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
      This is free software: you are free to change and redistribute it.
      There is NO WARRANTY, to the extent permitted by law.
  remoteSocket:
    exists: true
    path: /run/user/1000/podman/podman.sock
  security:
    apparmorEnabled: false
    capabilities: CAP_CHOWN,CAP_DAC_OVERRIDE,CAP_FOWNER,CAP_FSETID,CAP_KILL,CAP_NET_BIND_SERVICE,CAP_SETFCAP,CAP_SETGID,CAP_SETPCAP,CAP_SETUID,CAP_SYS_CHROOT
    rootless: true
    seccompEnabled: true
    seccompProfilePath: /usr/share/containers/seccomp.json
    selinuxEnabled: false
  serviceIsRemote: false
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: slirp4netns_1.2.1-1+b1_amd64
    version: |-
      slirp4netns version 1.2.1
      commit: 09e31e92fa3d2a1d3ca261adaeb012c8d75a8194
      libslirp: 4.8.0
      SLIRP_CONFIG_VERSION_MAX: 4
      libseccomp: 2.5.5
  swapFree: 0
  swapTotal: 0
  uptime: 25h 13m 26.00s (Approximately 1.04 days)
  variant: ""
plugins:
  authorization: null
  log:
  - k8s-file
  - none
  - passthrough
  - journald
  network:
  - bridge
  - macvlan
  - ipvlan
  volume:
  - local
registries: {}
store:
  configFile: /home/gc/.config/containers/storage.conf
  containerStore:
    number: 0
    paused: 0
    running: 0
    stopped: 0
  graphDriverName: overlay
  graphOptions: {}
  graphRoot: /home/gc/.local/share/containers/storage
  graphRootAllocated: 249425629184
  graphRootUsed: 6362935296
  graphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Supports shifting: "false"
    Supports volatile: "true"
    Using metacopy: "false"
  imageCopyTmpDir: /var/tmp
  imageStore:
    number: 0
  runRoot: /run/user/1000/containers
  transientStore: false
  volumePath: /home/gc/.local/share/containers/storage/volumes
version:
  APIVersion: 5.0.3
  Built: 0
  BuiltTime: Thu Jan  1 02:00:00 1970
  GitCommit: ""
  GoVersion: go1.22.5
  Os: linux
  OsArch: linux/amd64
  Version: 5.0.3

Podman in a container

No

Privileged Or Rootless

None

Upstream Latest Release

Yes

Additional environment details

No response

Additional information

No response

[rhatdan]

Please open a PR to fix?