Help command is racy

[crazy-max]

Description

Follow-up #4142 (comment)

Changes from #4129 seems to introduce a racy behavior for the help command.

Reproduce

Here is a script to repro:

#!/bin/bash

output=$(mktemp -d -t cli-output.XXXXXXXXXX)
#trap "rm -rf $output" EXIT
echo "Output: $output"

cat > "$output/orig.txt" <<EOL
Flag shorthand -h has been deprecated, please use --help

Usage: docker [OPTIONS] COMMAND

A self-sufficient runtime for containers

Common Commands:
 run Create and run a new container from an image
 exec Execute a command in a running container
 ps List containers
 build Build an image from a Dockerfile
 pull Download an image from a registry
 push Upload an image to a registry
 images List images
 login Log in to a registry
 logout Log out from a registry
 search Search Docker Hub for images
 version Show the Docker version information
 info Display system-wide information

Management Commands:
 builder Manage builds
 buildx* Docker Buildx (Docker Inc., v0.10.3)
 compose* Docker Compose (Docker Inc., v2.15.1)
 container Manage containers
 context Manage contexts
 dev* Docker Dev Environments (Docker Inc., v0.1.0)
 extension* Manages Docker extensions (Docker Inc., v0.2.18)
 image Manage images
 manifest Manage Docker image manifests and manifest lists
 network Manage networks
 plugin Manage plugins
 sbom* View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc., 0.6.0)
 scan* Docker Scan (Docker Inc., v0.25.0)
 scout* Command line tool for Docker Scout (Docker Inc., v0.6.0)
 system Manage Docker
 trust Manage trust on Docker images
 volume Manage volumes

Swarm Commands:
 config Manage Swarm configs
 node Manage Swarm nodes
 secret Manage Swarm secrets
 service Manage Swarm services
 stack Manage Swarm stacks
 swarm Manage Swarm

Commands:
 attach Attach local standard input, output, and error streams to a running container
 commit Create a new image from a container's changes
 cp Copy files/folders between a container and the local filesystem
 create Create a new container
 diff Inspect changes to files or directories on a container's filesystem
 events Get real time events from the server
 export Export a container's filesystem as a tar archive
 history Show the history of an image
 import Import the contents from a tarball to create a filesystem image
 inspect Return low-level information on Docker objects
 kill Kill one or more running containers
 load Load an image from a tar archive or STDIN
 logs Fetch the logs of a container
 pause Pause all processes within one or more containers
 port List port mappings or a specific mapping for the container
 rename Rename a container
 restart Restart one or more containers
 rm Remove one or more containers
 rmi Remove one or more images
 save Save one or more images to a tar archive (streamed to STDOUT by default)
 start Start one or more stopped containers
 stats Display a live stream of container(s) resource usage statistics
 stop Stop one or more running containers
 tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
 top Display the running processes of a container
 unpause Unpause all processes within one or more containers
 update Update configuration of one or more containers
 wait Block until one or more containers stop, then print their exit codes

Global Options:
 --config string Location of client config files (default "/home/crazy/.docker")
 -c, --context string Name of the context to use to connect to the daemon (overrides DOCKER_HOST env var and default context set with "docker context use")
 -D, --debug Enable debug mode
 -H, --host list Daemon socket(s) to connect to
 -l, --log-level string Set the logging level ("debug", "info", "warn", "error", "fatal") (default "info")
 --tls Use TLS; implied by --tlsverify
 --tlscacert string Trust certs signed only by this CA (default "/home/crazy/.docker/ca.pem")
 --tlscert string Path to TLS certificate file (default "/home/crazy/.docker/cert.pem")
 --tlskey string Path to TLS key file (default "/home/crazy/.docker/key.pem")
 --tlsverify Use TLS and verify the remote
 -v, --version Print version information and quit

Run 'docker COMMAND --help' for more information on a command.

For more help on how to use Docker, head to https://docs.docker.com/go/guides/
EOL

count=0
while true
do
 count=$((count+1))
 $1 --config /tmp/plugin-test-163662627 nonexistent -h 1>"$output/std-$count.out" 2>"$output/std-$count.err"
 if ! cmp -s "$output/orig.txt" "$output/std-$count.out"; then
 echo "Test $count: FAIL"
 diff "$output/orig.txt" "$output/std-$count.out"
 exit 1
 fi
 echo "Test $count: OK"
done

$ make -f docker.Makefile binary
...

$ /tmp/help-race.sh $(pwd)/build/docker
Output: /tmp/cli-output.De8S3dhjgQ
Test 1: OK
Test 2: OK
Test 3: OK
Test 4: OK
Test 5: OK
Test 6: OK
Test 7: OK
Test 8: OK
Test 9: OK
Test 10: OK
Test 11: OK
Test 12: OK
Test 13: OK
Test 14: OK
Test 15: OK
Test 16: OK
Test 17: OK
Test 18: OK
Test 19: OK
Test 20: OK
Test 21: OK
Test 22: OK
Test 23: OK
Test 24: OK
Test 25: OK
Test 26: OK
Test 27: OK
Test 28: OK
Test 29: OK
Test 30: OK
Test 31: OK
Test 32: OK
Test 33: OK
Test 34: OK
Test 35: OK
Test 36: FAIL
76a77
> wait Block until one or more containers stop, then print their exit codes

Expected behavior

No response

docker version

Client:
 Version: 23.0.0-130-g1c10101b17.m
 API version: 1.41 (downgraded from 1.43)
 Go version: go1.20.2
 Git commit: 1c10101b17
 Built: Fri Mar 31 12:27:59 2023
 OS/Arch: linux/amd64
 Context: default

docker info

Client:
 Context: default
 Debug Mode: false
 Plugins:
 buildx: Docker Buildx (Docker Inc.)
 Version: v0.10.0-rc2-175-g10dc9594
 Path: /home/crazy/.docker/cli-plugins/docker-buildx
 compose: Docker Compose (Docker Inc.)
 Version: v2.15.1
 Path: /usr/local/lib/docker/cli-plugins/docker-compose
 dev: Docker Dev Environments (Docker Inc.)
 Version: v0.1.0
 Path: /usr/local/lib/docker/cli-plugins/docker-dev
 extension: Manages Docker extensions (Docker Inc.)
 Version: v0.2.18
 Path: /usr/local/lib/docker/cli-plugins/docker-extension
 sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
 Version: 0.6.0
 Path: /usr/local/lib/docker/cli-plugins/docker-sbom
 scan: Docker Scan (Docker Inc.)
 Version: v0.25.0
 Path: /usr/local/lib/docker/cli-plugins/docker-scan
 scout: Command line tool for Docker Scout (Docker Inc.)
 Version: v0.6.0
 Path: /usr/local/lib/docker/cli-plugins/docker-scout

Additional Info

No response