"docker buildx ls --format json" lists each entry twice

### Contributing guidelines

- [x] I've read the [contributing guidelines](https://github.com/docker/buildx/blob/master/.github/CONTRIBUTING.md) and wholeheartedly agree

### I've found a bug and checked that ...

- [x] ... the documentation does not mention anything about my problem
- [x] ... there are no open or closed issues that are related to my problem

### Description

- `docker buildx ls --format json` lists each entry twice whereas `docker buildx ls` works properly

### Expected behaviour
The count of builders listed when running `"docker buildx ls"` (table format, default) vs. `"docker buildx ls --format json"` should be the same.   For example, running `"docker buildx ls"`, I get:

```console
$ docker buildx ls
NAME/NODE           DRIVER/ENDPOINT     STATUS    BUILDKIT   PLATFORMS
default             docker
 \_ default          \_ default         running   v0.17.3    linux/amd64 (+3), linux/arm64, linux/arm (+2), linux/ppc64le, (2 more)
desktop-linux*      docker
 \_ desktop-linux    \_ desktop-linux   running   v0.17.3    linux/amd64 (+3), linux/arm64, linux/arm (+2), linux/ppc64le, (2 more)
```

...then when running, `"docker buildx ls --format json"`, I should see the same two builders in [JSON-line](https://jsonlines.org/) format (each entry truncated with ellipsis for brevity):

```json
{"Name":"default","Driver":"docker", ...}
{"Name":"desktop-linux","Driver":"docker", ...}
```

### Actual behaviour

...instead, I see the entries are doubled (each entry truncated with ellipsis for brevity):
```json
{"Name":"default","Driver":"docker", ...}
{"Name":"default","Driver":"docker", ...}
{"Name":"desktop-linux","Driver":"docker", ...}
{"Name":"desktop-linux","Driver":"docker", ...}
```

The full output result of `docker buildx ls --format json` is attached:
[buildx_ls_out.json](https://github.com/user-attachments/files/18691003/buildx_ls_out.json)

### Buildx version

github.com/docker/buildx v0.19.2-desktop.1 412cbb151f1be3f8a94dc4eb03cd1b67f261dec5

### Docker info

```text
Client:
 Version:    27.4.0
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  ai: Ask Gordon - Docker Agent (Docker Inc.)
    Version:  v0.5.1
    Path:     /Users/wolf2/.docker/cli-plugins/docker-ai
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.19.2-desktop.1
    Path:     /Users/wolf2/.docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.31.0-desktop.2
    Path:     /Users/wolf2/.docker/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.37
    Path:     /Users/wolf2/.docker/cli-plugins/docker-debug
  desktop: Docker Desktop commands (Beta) (Docker Inc.)
    Version:  v0.1.0
    Path:     /Users/wolf2/.docker/cli-plugins/docker-desktop
  dev: Docker Dev Environments (Docker Inc.)
    Version:  v0.1.2
    Path:     /Users/wolf2/.docker/cli-plugins/docker-dev
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.27
    Path:     /Users/wolf2/.docker/cli-plugins/docker-extension
  feedback: Provide feedback, right in your terminal! (Docker Inc.)
    Version:  v1.0.5
    Path:     /Users/wolf2/.docker/cli-plugins/docker-feedback
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.4.0
    Path:     /Users/wolf2/.docker/cli-plugins/docker-init
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /Users/wolf2/.docker/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.15.1
    Path:     /Users/wolf2/.docker/cli-plugins/docker-scout

Server:
 Containers: 1
  Running: 1
  Paused: 0
  Stopped: 0
 Images: 2
 Server Version: 27.4.0
 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: 472731909fa34bd7bc9c087e4c27943f9835f111
 runc version: v1.1.13-0-g58aa920
 init version: de40ad0
 Security Options:
  seccomp
   Profile: unconfined
  cgroupns
 Kernel Version: 6.10.14-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: x86_64
 CPUs: 12
 Total Memory: 7.655GiB
 Name: docker-desktop
 ID: a9d33cb0-17b0-4031-9f64-34b0bd1774f3
 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/wolf2/Library/Containers/com.docker.docker/Data/docker-cli.sock
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: daemon is not using the default seccomp profile
```

### Builders list

```text
NAME/NODE           DRIVER/ENDPOINT     STATUS    BUILDKIT   PLATFORMS
default             docker
 \_ default          \_ default         running   v0.17.3    linux/amd64 (+3), linux/arm64, linux/arm (+2), linux/ppc64le, (2 more)
desktop-linux*      docker
 \_ desktop-linux    \_ desktop-linux   running   v0.17.3    linux/amd64 (+3), linux/arm64, linux/arm (+2), linux/ppc64le, (2 more)
```

### Configuration

`mininal_dockerfile.txt`:
```dockerfile
FROM scratch
```
```console
$ docker buildx build --progress plain -f mininal_dockerfile.txt .
#0 building with "desktop-linux" instance using docker driver

#1 [internal] load build definition from mininal_dockerfile.txt
#1 transferring dockerfile: 62B done
#1 DONE 0.0s

#2 [internal] load .dockerignore
#2 transferring context: 98B done
#2 DONE 0.0s

#3 exporting to image
#3 exporting layers done
#3 exporting manifest sha256:3a58ad119f0dae830e39299dd9d94100e3a764665fba8810f9a873d3ac716aec done
#3 exporting config sha256:471a1b8817eefb6569017c1a76f288e0d4e5c8476eb199485c469d0b033168bf done
#3 naming to moby-dangling@sha256:3a58ad119f0dae830e39299dd9d94100e3a764665fba8810f9a873d3ac716aec done
#3 DONE 0.0s

View build details: docker-desktop://dashboard/build/desktop-linux/desktop-linux/b814b21gpa45p9hto49guhayn
```

### Build logs

```text
N/A - not a build issue
```

### Additional info

I searched if this was already reported, but didn't find anything, or I didn't search properly.

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

"docker buildx ls --format json" lists each entry twice #2969

Contributing guidelines

I've found a bug and checked that ...

Description

Expected behaviour

Actual behaviour

Buildx version

Docker info

Builders list

Configuration

Build logs

Additional info

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

"docker buildx ls --format json" lists each entry twice #2969

Description

Contributing guidelines

I've found a bug and checked that ...

Description

Expected behaviour

Actual behaviour

Buildx version

Docker info

Builders list

Configuration

Build logs

Additional info

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions