star macro issue when no columns returned

[Datarogie]

If there are no columns returned in the macro it returns as commented out block but the issue is if the star macro isn't the last selected field in a select statement, it will place a comma on the outside of the comment block.

-- example
with
  final as (
    select
      {{ dbt_utils.star( ref("foo")) }},
      {{ dbt_utils.star( ref("bar")) }}
      
      from ...
)

select * from final

-- In this example let say the table foo doesn't return any columns. The compiled code looking like 
with
  final as (
    select
      /* no columns returned from star() macro */,
      bar_column1,
      bar_column2...
     
    from ...
)

select * from final
-- The above will fail to execute due to the comma outside of the comment block.

Simple fix would be to change the method being used to comment to simple double dash. Also believe this change will still comply with SQLFluff.

Reference source line

dbt-utils/macros/sql/star.sql

Line 26 in fc98e4e

{% do return("/* no columns returned from star() macro */") %}

[asarraf]

I am also thinking ... While =0 makes sense, what purpose does <0 serve in this line?

dbt-utils/macros/sql/star.sql

Line 16 in be74299

{%- if cols|length <= 0 -%}

[asarraf]

@Datarogie, Shouldn't this fail loud if no columns are returned from foo?
What use case would a change serve?

[asarraf]

The addition of , will help the user remind that something is missing otherwise, one might totally miss the issue that the first Ref isn't returning any column