docker stack config alters the final output, based on the order of compose files

Description

When giving multiple -c options to the docker stack config command, the order of the -c changes the final output

Reproduce

docker-compose.yml:

version: "3.5"

services:
  rabbitmq:
    hostname: rabbitmq
    image: rabbitmq:3.12.0-management
    ports:
      - "0:15672"
      - "0:5672"
    deploy:
      placement:
        constraints:
          - "node.role==manager"

docker-compose.override.yml

version: "3.5"
services:
  rabbitmq:
    labels:
      - "dk.cloudfactory.deployment.type=feature"

Below the outputs are different, based on the order of the options

 $ docker stack config -c docker-compose.yml -c docker-compose.override.yml
version: "3.5"
services:
  rabbitmq:
    deploy:
      placement:
        constraints:
        - node.role==manager
    hostname: rabbitmq
    image: rabbitmq:3.12.0-management
    labels:
      dk.cloudfactory.deployment.type: feature
    ports:
    - mode: ingress
      target: 5672
      protocol: tcp

$ docker stack config -c docker-compose.override.yml -c docker-compose.yml
version: "3.5"
services:
  rabbitmq:
    deploy:
      placement:
        constraints:
        - node.role==manager
    hostname: rabbitmq
    image: rabbitmq:3.12.0-management
    labels:
      dk.cloudfactory.deployment.type: feature
    ports:
    - mode: ingress
      target: 15672
      protocol: tcp
    - mode: ingress
      target: 5672
      protocol: tcp

Expected behavior

I expect that the order does not alter the final output, with the above examples

docker version

Client: Docker Engine - Community
 Version:           24.0.2
 API version:       1.43
 Go version:        go1.20.4
 Git commit:        cb74dfc
 Built:             Thu May 25 21:51:00 2023
 OS/Arch:           linux/amd64
 Context:           alpha2

Server: Docker Engine - Community
 Engine:
  Version:          24.0.5
  API version:      1.43 (minimum version 1.12)
  Go version:       go1.20.6
  Git commit:       a61e2b4
  Built:            Fri Jul 21 20:35:18 2023
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.6.22
  GitCommit:        8165feabfdfe38c65b599c4993d227328c231fca
 runc:
  Version:          1.1.8
  GitCommit:        v1.1.8-0-g82f18fe
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

Client: Docker Engine - Community
 Version:    24.0.2
 Context:    default
 Debug Mode: false
 Plugins:
WARNING: Plugin "/usr/local/lib/docker/cli-plugins/docker-buildx" is not valid: failed to fetch metadata: fork/exec /usr/local/lib/docker/cli-plugins/docker-buildx: no such file or directory
WARNING: Plugin "/usr/local/lib/docker/cli-plugins/docker-compose" is not valid: failed to fetch metadata: fork/exec /usr/local/lib/docker/cli-plugins/docker-compose: no such file or directory
WARNING: Plugin "/usr/local/lib/docker/cli-plugins/docker-dev" is not valid: failed to fetch metadata: fork/exec /usr/local/lib/docker/cli-plugins/docker-dev: no such file or directory
WARNING: Plugin "/usr/local/lib/docker/cli-plugins/docker-extension" is not valid: failed to fetch metadata: fork/exec /usr/local/lib/docker/cli-plugins/docker-extension: no such file or directory
WARNING: Plugin "/usr/local/lib/docker/cli-plugins/docker-sbom" is not valid: failed to fetch metadata: fork/exec /usr/local/lib/docker/cli-plugins/docker-sbom: no such file or directory
WARNING: Plugin "/usr/local/lib/docker/cli-plugins/docker-scan" is not valid: failed to fetch metadata: fork/exec /usr/local/lib/docker/cli-plugins/docker-scan: no such file or directory

Server:
 Containers: 214
  Running: 62
  Paused: 0
  Stopped: 152
 Images: 112
 Server Version: 24.0.5
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: systemd
 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: active
  NodeID: porxiy0qzy7wq3rywpghgbdwa
  Is Manager: true
  ClusterID: f2hw0leixfxyttqootnobbehp
  Managers: 1
  Nodes: 2
  Default Address Pool: 10.0.0.0/8
  SubnetSize: 24
  Data Path Port: 4789
  Orchestration:
   Task History Retention Limit: 5
  Raft:
   Snapshot Interval: 10000
   Number of Old Snapshots to Retain: 0
   Heartbeat Tick: 1
   Election Tick: 10
  Dispatcher:
   Heartbeat Period: 5 seconds
  CA Configuration:
   Expiry Duration: 3 months
   Force Rotate: 0
  Autolock Managers: false
  Root Rotation In Progress: false
  Node Address: 10.245.110.202
  Manager Addresses:
   10.245.110.202:2377
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 8165feabfdfe38c65b599c4993d227328c231fca
 runc version: v1.1.8-0-g82f18fe
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 5.15.0-79-generic
 Operating System: Ubuntu 22.04.3 LTS
 OSType: linux
 Architecture: x86_64
 CPUs: 16
 Total Memory: 62.72GiB
 Name: CFDOC02
 ID: 5e474919-6dae-427d-84b8-347e901960ec
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

Additional Info

No response

Start by reproducing the two docker stack config commands with docker-compose.yml and docker-compose.override.yml, then compare their final output. Trace the CLI's compose-file processing from the docker stack config entry point and determine why reversing -c options changes the ports. Done means both orders produce equivalent final output, with coverage for the reported files and commands.