debug exit code does not match connection test

[sdebruyn]

Describe the bug

When I run dbt debug, I would expect a successful exit code (0) when the connection test succeeds and an error code (>0) when the connection test fails. In 0.18.1 the exit code is always 0, regardless of the result of the test.

Steps To Reproduce

1. Make sure your profile works
2. Run dbt debug (connection test should succeed)
3. Run echo $? - observe that the output is 0
4. Mess up your profile (e.g. change the port to an invalid one)
5. Run dbt debug (connection test should fail)
6. Run echo $? - observe that the output is still 0

Expected behavior

A strictly positive exit code when the connection test fails.

Screenshots and log output

Mentioned in repro

System information

Any database

The output of dbt --version:

installed version: 0.18.1
   latest version: 0.18.1

Up to date!

Plugins:
  - sqlserver: 0.18.1
  - bigquery: 0.18.1
  - snowflake: 0.18.1
  - postgres: 0.18.1
  - redshift: 0.18.1

**The operating system you're using: Debian Buster

The output of python --version:
Python 3.8.7

[jtcohen6]

@sdebruyn I agree. If dbt debug manages to detect an error in your path, project, connection profile—or that you're not running from a dbt project at all—it feels like it should return 1 ("handled error") as the exit code instead of 0. I imagine could be useful for plugin maintainers who want to check various connection methods in CI (e.g. dbt-msft/dbt-sqlserver#65).

Is this a change you'd be interested in contributing?

[sdebruyn]

Sure :) Am I correct to assume that these 2 files are the only ones I'd need to change?

• https://github.com/fishtown-analytics/dbt/blob/dev/margaret-mead/test/integration/049_dbt_debug_test/test_debug.py
• https://github.com/fishtown-analytics/dbt/blob/dev/margaret-mead/core/dbt/task/debug.py

[jtcohen6]

That sounds right to me! We define an ExitCodes enum here:
https://github.com/fishtown-analytics/dbt/blob/1f927a374c8bd52a12a20d892fed9d59cffd04f4/core/dbt/utils.py#L32-L35

(ModelError sounds narrow; we might consider renaming someday to something more generic like HandledError.)

I think you'd want to pull that into task/debug.py, and conclude the run method by calling sys.exit() with the appropriate enum value.