Fix bug #2731 on stripping query comments for snowflake

[rvacaru]

resolves #2731

Description

Improved regex which removes EOL comments from snowflake multiline queries.

Checklist

• I have signed the CLA
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• I have updated the CHANGELOG.md and added information about my change to the "dbt next" section.

[cla-bot]

Thanks for your pull request, and welcome to our community! We require contributors to sign our Contributor License Agreement and we don't seem to have your signature on file. Check out this article for more information on why we have a CLA.

In order for us to review and merge your code, please submit the Individual Contributor License Agreement form attached above above. If you have questions about the CLA, or if you believe you've received this message in error, don't hesitate to ping @drewbanin.

CLA has not been signed by users: @rvacaru

[jtcohen6]

Thanks for the fix @rvacaru, and for the thorough unit testing!

Do you have a strong feeling about adding those in a new file (test_connections.py), versus adding it to the existing tests in test_snowflake_adapter.py? I ask because, someday, we'll want to split up these tests by adapter plugin, and it would be great to keep them closer together.

Finally, could you pull dev/margaret-mead and move your Changelog entry up to the v0.20.0 section (beneath a new ### Fixes subsection)?

[cla-bot]

Thanks for your pull request, and welcome to our community! We require contributors to sign our Contributor License Agreement and we don't seem to have your signature on file. Check out this article for more information on why we have a CLA.

In order for us to review and merge your code, please submit the Individual Contributor License Agreement form attached above above. If you have questions about the CLA, or if you believe you've received this message in error, don't hesitate to ping @drewbanin.

CLA has not been signed by users: @rvacaru-atb

[rvacaru]

You're welcome @jtcohen6 ! I moved the unit tests and updated the changelog like suggested, it should be ok now.

[jtcohen6]

Thanks @rvacaru! This is looking good.

I recommended one more unit test, for good measure, to be extra sure we're resolving the initially stated issue.

In testing this out I realized that there's a slight inconsistency arounnd query splitting and query headers, in that the latter only prepend the first split query.

If I have models/a.sql like:

{%- call statement('test') -%}
  select 1; -- comment
  select 2; -- comment
  select 3; -- comment
{%- endcall %}

select 1 as id

In the logs I see:

2021-01-20 08:09:01.951760 (Thread-1): Using snowflake connection "model.testy.a".
2021-01-20 08:09:01.951967 (Thread-1): On model.testy.a: /* {"app": "dbt", "dbt_version": "0.19.0rc2", "profile_name": "jaffle_shop", "target_name": "dev", "node_id": "model.testy.a"} */
select 1; -- comment
2021-01-20 08:09:02.190950 (Thread-1): SQL status: SUCCESS 1 in 0.24 seconds
2021-01-20 08:09:02.191158 (Thread-1): select 2;
2021-01-20 08:09:02.191315 (Thread-1): Using snowflake connection "model.testy.a".
2021-01-20 08:09:02.191677 (Thread-1): On model.testy.a: select 2; -- comment
2021-01-20 08:09:02.554744 (Thread-1): SQL status: SUCCESS 1 in 0.36 seconds
2021-01-20 08:09:02.554959 (Thread-1): select 3;
2021-01-20 08:09:02.555108 (Thread-1): Using snowflake connection "model.testy.a".
2021-01-20 08:09:02.555339 (Thread-1): On model.testy.a: select 3; -- comment
2021-01-20 08:09:02.890287 (Thread-1): SQL status: SUCCESS 1 in 0.33 seconds
...

That's not in scope for this PR, I just wanted to get it down in writing in case someone cares to open an issue later on.

[jtcohen6]

Could you add one more unit test that represents the original error case reported in #2731:

query5 = 'select 1; -- comment \nselect 2; -- comment \nselect 3; -- comment'
expected_query_5 = 'select 1; \nselect 2; \nselect 3;'

[rvacaru]

I've added the extra test. Let me know if there's anything more

[jtcohen6]

@rvacaru Thanks for the contribution!