[BUG] extends drops overriden attributes #13298
Description
Description
I have multiple docker compose files, each building on the previous one.
The middle one overrides the volumes array and the top one (extending the middle one) doesn't change volumes at all. However, when I try to launch it the container gets created without any volumes at all - not the original ones nor the overriding ones.
Steps To Reproduce
Create a compose file (c1) that extends c2 which overrides let's say the environment variables after extending c3 that has the original environment definition.
now You just need to set the cmd as a simple echo "${envvar}" (without it getting processed by compose) and observe that none of the values you defined are actually available. You can do the same with volumes
Compose Version
2.40.0
Docker Environment
Client:
Version: 28.5.1
Context: default
Debug Mode: false
Plugins:
compose: Docker Compose (Docker Inc.)
Version: 2.40.0
Path: /usr/lib/docker/cli-plugins/docker-compose
Server:
Containers: 4
Running: 1
Paused: 0
Stopped: 3
Images: 5
Server Version: 28.5.1
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Using metacopy: true
Native Overlay Diff: false
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 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: 75cb2b7193e4e490e9fbdc236c0e811ccaba3376.m
runc version:
init version: de40ad0
Security Options:
seccomp
Profile: builtin
cgroupns
Kernel Version: 6.17.2-arch1-1
Operating System: Arch Linux
OSType: linux
Architecture: x86_64
CPUs: 16
Total Memory: 13.49GiB
Name: IP5Pro
ID: b212eea5-d719-4bf0-8f4e-60407358f8c9
Docker Root Dir: /var/lib/docker
Debug Mode: false
Experimental: false
Insecure Registries:
::1/128
127.0.0.0/8
Live Restore Enabled: false
Anything else?
my compose files:
# template.yml
services:
database:
image: ${PROXY:-docker.io}/postgres:17-alpine
volumes:
- /home/git-ci/init-db.sh:/docker-entrypoint-initdb.d/init-db.sh
# local-test.yml
services:
database:
extends:
file: ./template.yml
service: database
volumes: !override # works without the !override
- ./init-db.sh:/docker-entrypoint-initdb.d/init-db.sh
# final one that you launch
services:
database:
extends:
file: local-test.yml
service: database