DVC exits with code 0 even if there was an error

[peper0]

Tested with dvc 0.70 from apt on Ubuntu:

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 18.04.2 LTS
Release:	18.04
Codename:	bionic

Can be easily reproduced with docker. The following example shows pulling from a nonexistent repository but the same problem is with errors of any kind.

Steps to reproduce
Create a following Dockerfile:

FROM ubuntu:18.04

RUN apt update
RUN apt install -y wget
RUN wget https://dvc.org/deb/dvc.list -O /etc/apt/sources.list.d/dvc.list
RUN apt update 
RUN apt install -y dvc
WORKDIR /work
RUN dvc init --no-scm
CMD bash -c 'dvc pull -r bleble && echo "command succesfull, but should not be"'

Build it:
$ docker build . -t dvc-bug

Run it:
$ docker run -it dvc-bug

Obtained result

ERROR: failed to pull data from the cloud - config file error: unable to find remote section 'bleble'

Having any troubles?. Hit us up at https://dvc.org/support, we are always happy to help!
command succesfull, but should not be

Expected result
No command succesfull, but should not be text in the output.

Mentioned earlier in #2038

[efiop]

Hi @peper0 !

Thank you for a very convenient reproducer! Indeed, I can reproduce this bug with binary dvc, but not with dvc installed from pip/brew/conda/etc. As a workaround, could you try installing dvc from one of those sources (i suppose pip will be the most convenient for you) and let us know if that works?

Related #2760 #2768

[efiop]

Looks like even things like dvc non-existing-command don't result in non-zero code for pyinstaller-built images. Investigating...

[peper0]

@efiop Can be reproduced with pip installed version when dvc is used as a python module:

python -m dvc pull -r bleble && echo "zero exit code"

However the wrapper script installed in .../bin/dvc fixes this issue. It is probably generated with a fastentrypoints module and handles the return value of main function correctly:

if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script\.pyw?|\.exe)?$', '', sys.argv[0])
    sys.exit(main())

However, pyinstaller use dvc/__main__.py directly, which contain invalid code (imo):

if __name__ == "__main__":
    main(sys.argv[1:])

[peper0]

I'he just created a merge request of a trivial patch that fixes it for the direct python usage (python -m dvc ...).

I couldn't test it for apt version, since I've had problems with building it.

[efiop]

@peper0 oh wow, amazing investigation! Thank you so much! 🙏 I think you are absolutely right about it. I'll give it a try in a second.

EDIT: tested and it works like a charm! 🎉

[efiop]

@peper0 I'll trigger a new release today, thank you!