Docker Stack Deploy error when using `depends_on` long syntax

Description

Given the following dummy docker-compose.yml

version: '3.9'
services:
  serviceA:
    image: serviceA:version1
  serviceB:
    image: serviceB:version2
    depends_on:
      serviceA:
        condition: service_completed_successfully

where serviceB finishes once run (in my real world example, it's a container that runs migrations on a database then dies)

The docker compose up command doesn't complain, however, the docker stack deploy command complains by saying that

services.serviceB.depends_on must be a list

I've tried running docker compose up and it doesn't complain about that, so I assume it works for docker compose up but not for docker stack deploy

Documentation regarding long syntax of depends_on can be found here
https://docs.docker.com/compose/compose-file/#long-syntax-1

Reproduce

1. Create the docker-compose.yml file I showed
2. Execute docker stack deploy --compose-file docker-compose.yml example-stack

Expected behavior

The stack should start creating. With the example file I provided, it should complain that image serviceA doesn't exist because it's an example, but with real world images it should work and start the stack. However, what actually ends up happening is the error i stated above about the depends on not being a list.

docker version

Client: Docker Engine - Community
 Version:           20.10.9
 API version:       1.41
 Go version:        go1.16.8
 Git commit:        c2ea9bc
 Built:             Mon Oct  4 16:08:29 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.9
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.16.8
  Git commit:       79ea9d3
  Built:            Mon Oct  4 16:06:37 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.6.8
  GitCommit:        9cd3357b7fd7218e4aec3eae239db1f68a5a6ec6
 runc:
  Version:          1.1.4
  GitCommit:        v1.1.4-0-g5fd4c4d
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

Client:
 Context:    default
 Debug Mode: false
 Plugins:
  app: Docker App (Docker Inc., v0.9.1-beta3)
  buildx: Build with BuildKit (Docker Inc., v0.6.3-docker)
  compose: Docker Compose (Docker Inc., v2.6.0)
  scan: Docker Scan (Docker Inc., v0.9.0)

Server:
 Containers: 3
  Running: 1
  Paused: 0
  Stopped: 2
 Images: 20
 Server Version: 20.10.9
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 1
 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: olm6j3as729ahukyet1j199mj
  Is Manager: true
  ClusterID: oj0ovckoc67ev73rqj093a052
  Managers: 1
  Nodes: 1
  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: 10.0.0.76
  Manager Addresses:
   10.0.0.76:2377
 Runtimes: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 9cd3357b7fd7218e4aec3eae239db1f68a5a6ec6
 runc version: v1.1.4-0-g5fd4c4d
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: default
 Kernel Version: 5.4.0-132-generic
 Operating System: Linux Mint 20.3
 OSType: linux
 Architecture: x86_64
 CPUs: 8
 Total Memory: 31.29GiB
 Name: worklaptop
 ID: OVQD:AGQF:NNW2:HPOW:4DNN:CDIK:JKYR:4DSN:YDJX:7XFJ:XJSR:JTXB
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: No swap limit support

Additional Info

No response

Start by reproducing the issue with the provided docker-compose.yml and the docker stack deploy --compose-file command. Trace how the stack command validates the long-form depends_on value, then add or update coverage for this example; done means the command no longer rejects the mapping solely because it is not a list.