Ansible Lint crashes if it is not run from the git repository

[tadeboro]

Summary

Running ansible-lint --version from anywhere but a git repository results in a crash with a stacktrace.

Issue Type

• Bug Report

Ansible and Ansible Lint details

Ansible Lint version: 5.1.1 (cannot paste --version output because the program crashes).

• ansible-lint installation method: one of pip, OS package

OS / ENVIRONMENT

STEPS TO REPRODUCE

Run ansible-lint --version from the /tmp folder, for example.

$ ansible-lint --version
Traceback (most recent call last):
  File "/home/tadej/tmp/venv/bin/ansible-lint", line 33, in <module>
    sys.exit(load_entry_point('ansible-lint', 'console_scripts', 'ansible-lint')())
  File "/home/tadej/xlab/ansible/ansible-lint/src/ansiblelint/__main__.py", line 299, in _run_cli_entrypoint
    sys.exit(main(sys.argv))
  File "/home/tadej/xlab/ansible/ansible-lint/src/ansiblelint/__main__.py", line 196, in main
    initialize_options(argv[1:])
  File "/home/tadej/xlab/ansible/ansible-lint/src/ansiblelint/__main__.py", line 83, in initialize_options
    new_options = cli.get_config(arguments or [])
  File "/home/tadej/xlab/ansible/ansible-lint/src/ansiblelint/cli.py", line 385, in get_config
    project_dir = guess_project_dir(options.config_file)
  File "/home/tadej/xlab/ansible/ansible-lint/src/ansiblelint/file_utils.py", line 273, in guess_project_dir
    path = result.stdout.splitlines()[0]
IndexError: list index out of range

Desired Behaviour

Ansible Lint should print out its version number.

Additional information

git blame reported #1661 as the source of the breakage. It was a bit tricky to find the real cause because that one commit contains a bunch of refactoring alongside the actual fix. The error was introduced in https://github.com/ansible-community/ansible-lint/pull/1661/files#diff-4525388e8f05ebb145c2c2366127aba4f3716da965f32a91b70b5c4a0eafd35aL268-L269 because now we do not check the exit code of the git command anymore.

Originally reported by Amin.

[tadeboro]

/cc @xabinapal Just for reference.

[ssbarnea]

Found it myself few minutes ago and already got a fix, but now I am writing tests to prevent future regressions.