labels with list syntax are broken in docker compose v2.23.0

[ghelyar]

Description

according to the compose spec for labels, there are two syntaxes available - list syntax and dictionary/object/map syntax

in 2.22.0, both of these worked, but in 2.23.0, list syntax does not work.

Steps To Reproduce

1. Create a docker-compose.yml file:

   services:
     hello_world:
       image: hello-world
       labels:
         - a=b
         - c

2. on docker compose 2.23.0, run docker compose config or docker compose up

The error in 2.23.0 is:

1 error(s) decoding:

* error decoding 'labels': invalid label ["a=b" "c"]

Compose Version

Docker Compose version v2.23.0

Docker Environment

Client: Docker Engine - Community
 Version:    24.0.6
 Context:    default
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.11.2
    Path:     /usr/libexec/docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.23.0
    Path:     /usr/libexec/docker/cli-plugins/docker-compose

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 19
 Server Version: 24.0.6
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: false
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 61f9fd88f79f081d64d6fa3bb1a0dc71ec870523
 runc version: v1.1.9-0-gccaecfc
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: builtin

Anything else?

No response

[ndeloof]

This has been fixed by compose-spec/compose-go#475

[mjgasiorfp]

Still getting this error:

* error decoding 'labels': invalid label ["noupstream"]

When it was defined as:

  labels:
    - 'noupstream'

Started to work when switched to:

  labels:
    - 'noupstream=true'

Compose version:

Docker Compose version v2.23.0-desktop.1

Downgraded to compose 2.18 and the issue hasn't appeared.

[seinshah]

docker desktop v4.26.1 with docker compose version v2.23.3 fixes the problem