stdout is not flushed in healthckeck

[orion160]

Issue Description

When using healthcheck at podman compose it doesnt show the output of curl

healthcheck:
      test: curl -sSf http://webpy:8000/healthcheck || exit 1

for output the result I have to append echo

healthcheck:
      test: curl -sSf http://webpy:8000/healthcheck && echo || exit 1

Steps to reproduce the issue

run podman compose with

healthcheck:
      test: curl -sSf http://webpy:8000/healthcheck || exit 1

Describe the results you received

No output in the container logs
{
"Start": "2024-08-11T17:28:50.911061254-04:00",
"End": "2024-08-11T17:28:51.216155453-04:00",
"ExitCode": 0,
"Output": ""
}

Describe the results you expected

output the response of the request

{
"Start": "2024-08-11T17:28:50.911061254-04:00",
"End": "2024-08-11T17:28:51.216155453-04:00",
"ExitCode": 0,
"Output": "{"status":"OK"}"
}

podman info output

host:
  arch: amd64
  buildahVersion: 1.36.0
  cgroupControllers:
  - cpu
  - io
  - memory
  - pids
  cgroupManager: systemd
  cgroupVersion: v2
  conmon:
    package: conmon-2.1.10-1.fc40.x86_64
    path: /usr/bin/conmon
    version: 'conmon version 2.1.10, commit: '
  cpuUtilization:
    idlePercent: 89.07
    systemPercent: 1.44
    userPercent: 9.49
  cpus: 4
  databaseBackend: sqlite
  distribution:
    distribution: fedora
    variant: workstation
    version: "40"
  eventLogger: journald
  freeLocks: 2045
  hostname: fedora
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 524288
      size: 65536
    uidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 524288
      size: 65536
  kernel: 6.10.3-200.fc40.x86_64
  linkmode: dynamic
  logDriver: journald
  memFree: 1859588096
  memTotal: 7890804736
  networkBackend: netavark
  networkBackendInfo:
    backend: netavark
    dns:
      package: aardvark-dns-1.12.1-1.fc40.x86_64
      path: /usr/libexec/podman/aardvark-dns
      version: aardvark-dns 1.12.1
    package: netavark-1.12.1-1.fc40.x86_64
    path: /usr/libexec/podman/netavark
    version: netavark 1.12.1
  ociRuntime:
    name: crun
    package: crun-1.15-1.fc40.x86_64
    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 +CRIU +LIBKRUN +WASM:wasmedge +YAJL
  os: linux
  pasta:
    executable: /usr/bin/pasta
    package: passt-0^20240726.g57a21d2-1.fc40.x86_64
    version: |
      pasta 0^20240726.g57a21d2-1.fc40.x86_64
      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: false
    path: /run/user/1000/podman/podman.sock
  rootlessNetworkCmd: pasta
  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: true
  serviceIsRemote: false
  slirp4netns:
    executable: ""
    package: ""
    version: ""
  swapFree: 2754760704
  swapTotal: 4096782336
  uptime: 10h 55m 54.00s (Approximately 0.42 days)
  variant: ""
plugins:
  authorization: null
  log:
  - k8s-file
  - none
  - passthrough
  - journald
  network:
  - bridge
  - macvlan
  - ipvlan
  volume:
  - local
registries:
  search:
  - registry.fedoraproject.org
  - registry.access.redhat.com
  - docker.io
store:
  configFile: /home/orion/.config/containers/storage.conf
  containerStore:
    number: 1
    paused: 0
    running: 1
    stopped: 0
  graphDriverName: overlay
  graphOptions: {}
  graphRoot: /home/orion/.local/share/containers/storage
  graphRootAllocated: 134660227072
  graphRootUsed: 6261829632
  graphStatus:
    Backing Filesystem: btrfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Supports shifting: "false"
    Supports volatile: "true"
    Using metacopy: "false"
  imageCopyTmpDir: /var/tmp
  imageStore:
    number: 64
  runRoot: /run/user/1000/containers
  transientStore: false
  volumePath: /home/orion/.local/share/containers/storage/volumes
version:
  APIVersion: 5.1.2
  Built: 1720569600
  BuiltTime: Tue Jul  9 20:00:00 2024
  GitCommit: ""
  GoVersion: go1.22.5
  Os: linux
  OsArch: linux/amd64
  Version: 5.1.2

Podman in a container

No

Privileged Or Rootless

None

Upstream Latest Release

Yes

Additional environment details

No response

Additional information

No response

[Luap99]

Duplicate of #23332

Fixed in podman v5.2