[BUG] Docker Compose develop.watch.0 Additional property initial_sync is not allowed

[jcasse]

Description

macOS Tahoe 26.3 (25D125)
Docker Desktop 4.40.0 (187762)
Docker Compose version v2.34.0-desktop.1

services:

  my-service:
    image: ${APP_NAME}
    pull_policy: never
    build:
      context: ${PROJECT_ROOT}
      target: ${TARGET}
      args:
        - BASE_IMAGE=python:3.12-bookworm
    container_name: ${APP_NAME}
    develop:
      watch:
        - action: sync+restart
          initial_sync: true
          path: ${PROJECT_ROOT}/src
          target: /app/src
          ignore:
            - __pycache__

Current Behavior:
Executing docker compose up --watch returns the error develop.watch.0 Additional property initial_sync is not allowed.
If I remove initial_sync: true, it works: changes to the code trigger a restart of the container.

Thank you

Steps To Reproduce

1. In the environment described above
2. With the docker-compose.yaml shown above
3. Execute docker compose up --watch
4. The output on the terminal will be develop.watch.0 Additional property initial_sync is not allowed

Compose Version

❯ docker compose version
Docker Compose version v2.34.0-desktop.1
❯ docker-compose version
Docker Compose version v2.34.0-desktop.1
❯

Docker Environment

❯ docker info
Client:
 Version:    28.0.4
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  ai: Docker AI Agent - Ask Gordon (Docker Inc.)
    Version:  v1.1.3
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-ai
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.22.0-desktop.1
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-buildx
  cloud: Docker Cloud (Docker Inc.)
    Version:  0.2.20
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-cloud
  compose: Docker Compose (Docker Inc.)
    Version:  v2.34.0-desktop.1
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.38
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-debug
  desktop: Docker Desktop commands (Beta) (Docker Inc.)
    Version:  v0.1.6
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-desktop
  dev: Docker Dev Environments (Docker Inc.)
    Version:  v0.1.2
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-dev
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.27
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-extension
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.4.0
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-init
  model: Docker Model Runner (Docker Inc.)
    Version:  v0.1.4
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-model
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.17.0
    Path:     /Users/juan.casse/.docker/cli-plugins/docker-scout

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 10
 Server Version: 28.0.4
 Storage Driver: overlayfs
  driver-type: io.containerd.snapshotter.v1
 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 splunk syslog
 CDI spec directories:
  /etc/cdi
  /var/run/cdi
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 753481ec61c7c8955a23d6ff7bc8e4daed455734
 runc version: v1.2.5-0-g59923ef
 init version: de40ad0
 Security Options:
  seccomp
   Profile: unconfined
  cgroupns
 Kernel Version: 6.10.14-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: aarch64
 CPUs: 14
 Total Memory: 11.67GiB
 Name: docker-desktop
 ID: b35be725-a9ad-4934-a044-2e508d993691
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Labels:
  com.docker.desktop.address=unix:///Users/juan.casse/Library/Containers/com.docker.docker/Data/docker-cli.sock
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  ::1/128
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: DOCKER_INSECURE_NO_IPTABLES_RAW is set
WARNING: daemon is not using the default seccomp profile
❯

Anything else?

No response

[ndeloof]

Your docker compose version is obsolete