/images/{name}/json does not return image Entrypoint if null #50134
Description
Description
Since at least Docker 28.2.2, the API response of /images/{name}/json and as such the output of docker inspect no longer contains the image entrypoint if it is null under Config.Entrypoint. Some tools may rely on this, and it is not documented that this field can be missing, see https://docs.docker.com/reference/api/engine/version/v1.50/#tag/Image/operation/ImageInspect
There was also nothing in the changelog about this.
It also doesn't document that it can be null, even if it can be, but that was the case even before this update.
My guess is this is an unintended side effect of the removal of other unrelated API fields in the last API update.
Compare the output of docker inspect alpine:
v 28.2.2:
[
{
"Id": "sha256:cea2ff433c610f5363017404ce989632e12b953114fefc6f597a58e813c15d61",
"RepoTags": [
"alpine:latest"
],
"RepoDigests": [
"alpine@sha256:8a1f59ffb675680d47db6337b49d22281a139e9d709335b492be023728e11715"
],
"Parent": "",
"Comment": "buildkit.dockerfile.v0",
"Created": "2025-05-30T16:20:41Z",
"DockerVersion": "",
"Author": "",
"Config": {
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
],
"Cmd": [
"/bin/sh"
],
"WorkingDir": "/"
},
"Architecture": "amd64",
"Os": "linux",
"Size": 8309109,
"GraphDriver": {
"Data": {
"MergedDir": "/var/lib/docker/overlay2/0e810d6ad7dbaa82bf96ea24ee029317f8c0fe7f0c85200f023c56a38d0b62a0/merged",
"UpperDir": "/var/lib/docker/overlay2/0e810d6ad7dbaa82bf96ea24ee029317f8c0fe7f0c85200f023c56a38d0b62a0/diff",
"WorkDir": "/var/lib/docker/overlay2/0e810d6ad7dbaa82bf96ea24ee029317f8c0fe7f0c85200f023c56a38d0b62a0/work"
},
"Name": "overlay2"
},
"RootFS": {
"Type": "layers",
"Layers": [
"sha256:fd2758d7a50e2b78d275ee7d1c218489f2439084449d895fa17eede6c61ab2c4"
]
},
"Metadata": {
"LastTagTime": "0001-01-01T00:00:00Z"
}
}
]
v 27.5.1:
[
{
"Id": "sha256:cea2ff433c610f5363017404ce989632e12b953114fefc6f597a58e813c15d61",
"RepoTags": [
"alpine:latest"
],
"RepoDigests": [
"alpine@sha256:8a1f59ffb675680d47db6337b49d22281a139e9d709335b492be023728e11715"
],
"Parent": "",
"Comment": "buildkit.dockerfile.v0",
"Created": "2025-05-30T16:20:41Z",
"DockerVersion": "",
"Author": "",
"Config": {
"Hostname": "",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
],
"Cmd": [
"/bin/sh"
],
"Image": "",
"Volumes": null,
"WorkingDir": "/",
"Entrypoint": null,
"OnBuild": null,
"Labels": null
},
"Architecture": "amd64",
"Os": "linux",
"Size": 8309109,
"GraphDriver": {
"Data": {
"MergedDir": "/var/lib/docker/overlay2/7f9290058d9027eceb0a259442c0ba86e84e8af7228581a6eaa8bdeb3e21938e/merged",
"UpperDir": "/var/lib/docker/overlay2/7f9290058d9027eceb0a259442c0ba86e84e8af7228581a6eaa8bdeb3e21938e/diff",
"WorkDir": "/var/lib/docker/overlay2/7f9290058d9027eceb0a259442c0ba86e84e8af7228581a6eaa8bdeb3e21938e/work"
},
"Name": "overlay2"
},
"RootFS": {
"Type": "layers",
"Layers": [
"sha256:fd2758d7a50e2b78d275ee7d1c218489f2439084449d895fa17eede6c61ab2c4"
]
},
"Metadata": {
"LastTagTime": "0001-01-01T00:00:00Z"
}
}
]
Reproduce
- docker pull alpine
- docker inspect alpine
Expected behavior
The response should list Entrypoint under Config.
docker version
Client: Docker Engine - Community
Version: 28.2.2
API version: 1.50
Go version: go1.24.3
Git commit: e6534b4
Built: Fri May 30 12:09:03 2025
OS/Arch: linux/amd64
Context: default
Server: Docker Engine - Community
Engine:
Version: 28.2.2
API version: 1.50 (minimum version 1.24)
Go version: go1.24.3
Git commit: 45873be
Built: Fri May 30 12:07:24 2025
OS/Arch: linux/amd64
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: de40ad0docker info
Client: Docker Engine - Community
Version: 28.2.2
Context: default
Debug Mode: false
Plugins:
buildx: Docker Buildx (Docker Inc.)
Version: v0.24.0
Path: /usr/libexec/docker/cli-plugins/docker-buildx
compose: Docker Compose (Docker Inc.)
Version: v2.36.2
Path: /usr/libexec/docker/cli-plugins/docker-compose
Server:
Containers: 0
Running: 0
Paused: 0
Stopped: 0
Images: 1
Server Version: 28.2.2
Storage Driver: overlay2
Backing Filesystem: btrfs
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 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: 05044ec0a9a75232cad458027ca83437aae3f4da
runc version: v1.2.5-0-g59923ef
init version: de40ad0
Security Options:
seccomp
Profile: builtin
cgroupns
Kernel Version: 6.11.11-300.fc41.x86_64
Operating System: Fedora Linux 41 (Workstation Edition)
OSType: linux
Architecture: x86_64
CPUs: 4
Total Memory: 7.747GiB
Name: fedora.fritz.box
ID: 71d302ed-8770-4a6a-bccb-7a46ecece0de
Docker Root Dir: /var/lib/docker
Debug Mode: false
Experimental: false
Insecure Registries:
::1/128
127.0.0.0/8
Live Restore Enabled: falseAdditional Info
No response