Linting warnings sometimes clash with `--call outline` output

Contributing guidelines

• I've read the contributing guidelines and wholeheartedly agree

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

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

Description

Linting warnings (and build progress) are printed on STDERR, which seems to race with STDOUT output, causing warnings to be clashing with the output;

Expected behaviour

Warnings to be printed after the output, or after the progress output;

Actual behaviour

See above

Buildx version

docker buildx version github.com/docker/buildx v0.20.1-desktop.2 aaf7c2bc7f9ec3afee1cec77d671845a4b57a0c8

Docker info

Client:
 Version:    27.5.1
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  ai: Ask Gordon - Docker Agent (Docker Inc.)
    Version:  v0.7.3
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-ai
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.20.1-desktop.2
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.32.4-desktop.1
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.38
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-debug
  desktop: Docker Desktop commands (Beta) (Docker Inc.)
    Version:  v0.1.4
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-desktop
  dev: Docker Dev Environments (Docker Inc.)
    Version:  v0.1.2
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-dev
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.27
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-extension
  feedback: Provide feedback, right in your terminal! (Docker Inc.)
    Version:  v1.0.5
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-feedback
  harmonia: Extend your localhost with cloud workspaces (Docker Inc.)
    Version:  0.13.170
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-harmonia
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.4.0
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-init
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.16.1
    Path:     /Applications/Docker.app/Contents/Resources/cli-plugins/docker-scout
  shell: Open a browser shell on the Docker Host. (thaJeztah)
    Version:  v0.0.1
    Path:     /Users/thajeztah/.docker/cli-plugins/docker-shell

Server:
 Containers: 4
  Running: 4
  Paused: 0
  Stopped: 0
 Images: 12
 Server Version: 27.5.1
 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: active
  NodeID: qyeriqk20al6hy4y869d08ff5
  Is Manager: true
  ClusterID: b7ebdxm5mmtstysnvf2u2ncln
  Managers: 1
  Nodes: 1
  Default Address Pool: 10.0.0.0/8
  SubnetSize: 24
  Data Path Port: 4789
  Orchestration:
   Task History Retention Limit: 5
  Raft:
   Snapshot Interval: 10000
   Number of Old Snapshots to Retain: 0
   Heartbeat Tick: 1
   Election Tick: 10
  Dispatcher:
   Heartbeat Period: 5 seconds
  CA Configuration:
   Expiry Duration: 3 months
   Force Rotate: 0
  Autolock Managers: false
  Root Rotation In Progress: false
  Node Address: 192.168.65.3
  Manager Addresses:
   192.168.65.3:2377
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: bcc810d6b9066471b0b6fa75f557a15a1cbf31bb
 runc version: v1.2.4-0-g6c52b3f
 init version: de40ad0
 Security Options:
  seccomp
   Profile: unconfined
  cgroupns
 Kernel Version: 6.12.5-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: aarch64
 CPUs: 10
 Total Memory: 7.653GiB
 Name: docker-desktop
 ID: 58815d06-8744-4af3-b6f1-7a88003318ad
 Docker Root Dir: /var/lib/docker
 Debug Mode: true
  File Descriptors: 164
  Goroutines: 318
  System Time: 2025-02-10T09:17:34.489766543Z
  EventsListeners: 19
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Labels:
  com.docker.desktop.address=unix:///Users/thajeztah/Library/Containers/com.docker.docker/Data/docker-cli.sock
 Experimental: false
 Insecure Registries:
  host.docker.internal:5001
  host.docker.internal:5002
  hubproxy.docker.internal:5555
  127.0.0.0/8
 Live Restore Enabled: false

Builders list

irrelevant

Configuration

• Dockerfile from this PR; https://github.com/docker/cli/pull/5815

Build logs

Additional info

No response

Start with the --call outline output path and the handling of linting warnings and build progress on STDERR versus STDOUT. Reproduce the clash using the Dockerfile from docker/cli PR 5815; done means warnings appear after the outline or progress output without overlapping it.