`docker compose exec -T` outputs garbage (SOH and NUL) characters

[gustafc]

Description of the issue

The docker-compose exec and docker compose exec style invocations generate slightly different output, which I believe to be a bug in the docker compose exec flavour.

Here's the long and short of it, where I run echo without any arguments in a service running Ubuntu:

$ cat docker-compose.yml
services:
  demo:
    image: ubuntu
    entrypoint: sleep 1000000
$ docker compose up --detach
[+] Running 2/2
 ⠿ Network docker-compose-exec-bug_default   Created                                                                                                                                                   3.6s
 ⠿ Container docker-compose-exec-bug_demo_1  Started                                                                                                                                                   2.3s
$ docker-compose exec -T demo echo | od -a
0000000   nl                                                            
0000001
$ docker compose exec -T demo echo | od -a
0000000  soh nul nul nul nul nul nul soh  nl                            
0000011

echo without any arguments should just output a newline (nl) and nothing else. That is exactly what the docker-compose exec style invocation outputs, but docker compose exec outputs a bunch of soh and nul characters before the command output. This happens regardless of which command is invoked (I stumbled upon it when using psql in a Postgres container).

If this is not the place to report docker compose bugs, I humbly apologise and ask for directions where to report this bug :)

Context information (for bug reports)

Output of docker-compose version

docker-compose version 1.29.1, build c34c88b2
docker-py version: 5.0.0
CPython version: 3.9.0
OpenSSL version: OpenSSL 1.1.1h  22 Sep 2020

Output of docker version

Client:
 Cloud integration: 1.0.14
 Version:           20.10.6
 API version:       1.41
 Go version:        go1.16.3
 Git commit:        370c289
 Built:             Fri Apr  9 22:46:57 2021
 OS/Arch:           darwin/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.6
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.13.15
  Git commit:       8728dd2
  Built:            Fri Apr  9 22:44:56 2021
  OS/Arch:          linux/amd64
  Experimental:     true
 containerd:
  Version:          1.4.4
  GitCommit:        05f951a3781f4f2c1911b05e61c160e9c30eaa8e
 runc:
  Version:          1.0.0-rc93
  GitCommit:        12644e614e25b05da6fd08a38ffa0cfe1903fdec
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Output of docker-compose config (Make sure to add the relevant -f and other flags)

services:
  demo:
    entrypoint: sleep 1000000
    image: ubuntu
version: '3.9'

Bonus: Output of docker compose config

services:
  demo:
    entrypoint:
    - sleep
    - "1000000"
    image: ubuntu
    networks:
      default: null
networks:
  default:
    name: docker-compose-exec-bug_default

Steps to reproduce the issue

1. Run docker-compose exec -T any-service-that-has-echo echo | od -a
2. Run docker compose exec -T any-service-that-has-echo echo | od -a
3. Compare the results

Observed result

• docker-compose exec outputs just the nl from echo
• docker compose exec outputs soh and nul characters before the nl from echo

Expected result

docker compose exec should behave as docker-compose exec does, and just output a newline

Stacktrace / full error message

N/A

Additional information

In my reproduction example above, I use docker compose up. Using docker-compose up makes no difference to the various exec results.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[gustafc]

I'd like to point out that this is still a problem. Btw, more system info:

$ docker compose version
Docker Compose version 2.0.0-beta.1

[stale[bot]]

This issue has been automatically marked as not stale anymore due to the recent activity.

[pmav99]

Still an issue on 2.2.3. When -T is used, then the output is malformed:

$ dcmp exec -T db cat /etc/hosts
127.0.0.1	localhost
                         ::1	localhost ip6-localhost ip6-loopback
                                                                    fe00::0	ip6-localnet
                                                                                            ff00::0	ip6-mcastprefix
                                                                                                                       ff02::1	ip6-allnodes
                                                                                                                                            ff02::2	ip6-allrouters
                                                                                                                                                                      192.168.112.2	8cfaac435e41

VS

$  dcmp exec db cat /etc/hosts   
127.0.0.1	localhost
::1	localhost ip6-localhost ip6-loopback
fe00::0	ip6-localnet
ff00::0	ip6-mcastprefix
ff02::1	ip6-allnodes
ff02::2	ip6-allrouters
192.168.112.2	8cfaac435e41

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[pmav99]

On 2.6.1 this seems to have been fixed.

[stale[bot]]

This issue has been automatically closed because it had not recent activity during the stale period.