[CT-504] Intermittent test failure in 'selected_resource' test.

[gshank]

Pull request #5001 added a selected resource feature for the context and a test. We are seeing intermittent failures with the error message:

16:08:01  Completed with 2 errors and 0 warnings:
16:08:01  
16:08:01  Compilation Error in model model2 (models/model2.sql)
16:08:01    dbt was unable to infer all dependencies for the model "model2".
16:08:01    This typically happens when ref() is placed within a conditional block.
16:08:01    
16:08:01    To fix this, add the following hint to the top of the model "model2":
16:08:01    
16:08:01    -- depends_on: {{ ref('model1') }}
16:08:01    
16:08:01    > in model model2 (models/model2.sql)
16:08:01    > called by model model2 (models/model2.sql)
16:08:01  
16:08:01  Compilation Error in snapshot cc_all_snapshot (snapshots/my_snapshot.sql)
16:08:01    dbt was unable to infer all dependencies for the model "cc_all_snapshot".
16:08:01    This typically happens when ref() is placed within a conditional block.
16:08:01    
16:08:01    To fix this, add the following hint to the top of the model "cc_all_snapshot":
16:08:01    
16:08:01    -- depends_on: {{ ref('model2') }}
16:08:01    
16:08:01    > in snapshot cc_all_snapshot (snapshots/my_snapshot.sql)
16:08:01    > called by snapshot cc_all_snapshot (snapshots/my_snapshot.sql)

Also having a whole separate file for it in core/dbt/selected_resource.py is kind of overkill. It should be in some other file. In addition we should try hard to implement it in a way that doesn't use a global file variable, because they are a bad idea in general (despite the fact that we have a number of them) and they all need to be reset for tests to run properly (and quite possibly any persistent server code).

[iknox-fa]

@gshank This came up in BLG today. We're going to point this with an AC of "make the intermittent errors stop" but not to avoid globals or change the code to live in another place. If you still feel strongly about those issues could you please open new tickets for them?

[leahwicz]

Let's create a ticket for the refactor and then when the time comes we can weigh the refactor vs fixing the test

[leahwicz]

@gshank could you close this out and open a new ticket with the work to make this not global anymore

[gshank]

Closing in favor of #6009