[BUG] compose up -d waits for service dependencies before detaching

[tralafiti]

Description

docker compose up -d waits for certain services to enter healthy state before detaching. I would expect this behavior only if --wait is set.

Steps To Reproduce

docker-compose.yml:

services:
  a:
    image: busybox
    command: sh -c "sleep 10"
    init: true
    network_mode: none
    healthcheck:
      test: [ "CMD-SHELL", "if [ -f /healthy ]; then exit 0; else (sleep 1 & touch /healthy); exit 1; fi" ]
      interval: 1s
      timeout: 1s
  b:
    image: busybox
    command: sh -c "sleep 10"
    init: true
    network_mode: none
    healthcheck:
      test: [ "CMD-SHELL", "if [ -f /healthy ]; then exit 0; else (sleep 3 & touch /healthy); exit 1; fi" ]
      interval: 1s
      timeout: 1s
    depends_on:
      a:
        condition: service_healthy

Unexpected: up -d waits for A to become healthy before detaching:

% time docker compose up -d 
[+] Running 2/2
 ✔ Container up-wait-a-1  Healthy                                          3.7s 
 ✔ Container up-wait-b-1  Started                                          3.7s 
[3.86s]

Adding --wait waits for A and B (as expected):

% time docker compose up -d --wait
[+] Running 2/2
 ✔ Container up-wait-a-1  Healthy                                          4.2s 
 ✔ Container up-wait-b-1  Healthy                                          8.2s 
[8.35s]

Removing depends_on from compose file restores expected behavior of immediate detach or optional wait:

% time docker compose up -d
[+] Running 2/2
 ✔ Container up-wait-b-1  Started                                          0.1s 
 ✔ Container up-wait-a-1  Started                                          0.1s 
[0.17s]

% time docker compose up -d --wait
[+] Running 2/2
 ✔ Container up-wait-b-1  Healthy                                          1.6s 
 ✔ Container up-wait-a-1  Healthy                                          1.6s 
[1.68s]

Compose Version

Docker Compose version v2.35.1-desktop.1

Docker Environment

Client:
 Version:           28.1.1
 API version:       1.49
 Go version:        go1.23.8
 Git commit:        4eba377
 Built:             Fri Apr 18 09:49:45 2025
 OS/Arch:           darwin/arm64
 Context:           desktop-linux

Server: Docker Desktop 4.41.2 (191736)
 Engine:
  Version:          28.1.1
  API version:      1.49 (minimum version 1.24)
  Go version:       go1.23.8
  Git commit:       01f442b
  Built:            Fri Apr 18 09:52:08 2025
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.7.27
  GitCommit:        05044ec0a9a75232cad458027ca83437aae3f4da
 runc:
  Version:          1.2.5
  GitCommit:        v1.2.5-0-g59923ef
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Anything else?

No response

[ndeloof]

As b depends on a with service_healthy condition, Compose MUST wait for a to become healthy so it can start b. This is the expected behavior. (depends_on is implemented by compose, not docker engine)