[CT-2944] [Bug] Ambiguous reference error for tests when model name is duplicated across packages

[jtcohen6]

Is this a new bug in dbt-core?

• I believe this is a new bug in dbt-core
• I have searched the existing issues, and I could not find an existing issue for this bug

Current Behavior

When:

• a model with the same name is defined in multiple projects
• those projects are installed in the same runtime environment (via packages)
• at least one of those models has a generic test defined

dbt raises an ambiguous reference error

Expected Behavior

dbt should successfully parse my project, and resolve tests to reference the model in the same project/package where they are defined

Steps To Reproduce

Create a project named my_dbt_project, and another local project under a subdirectory named mypkg/.

Within the root project:

# dbt_project.yml
name: my_dbt_project
profile: default

# dependencies.yml OR packages.yml
packages:
  - local: mypkg

-- models/model_a.sql
select 1 as id

# models/config.yml
models:
  - name: model_a
    columns:
      - name: id
        tests:
          - unique

Within the package mypkg, add the exact same model with the exact same config:

# mypkg/dbt_project.yml
name: mypkg

-- mypkg/models/model_a.sql
select 1 as id

# mypkg/models/config.yml
models:
  - name: model_a
    columns:
      - name: id
        tests:
          - unique

From the root project:

$ dbt deps
14:10:31  Running with dbt=1.6.0
14:10:31  Installing mypkg
14:10:31  Installed from <local @ mypkg>

$ dbt --no-partial-parse parse
14:10:43  Running with dbt=1.6.0
14:10:43  Registered adapter: postgres=1.6.0
14:10:44  Encountered an error:
Compilation Error
  When referencing 'model_a', dbt found nodes in multiple packages: 'model.my_dbt_project.model_a', 'model.mypkg.model_a'
  To fix this, use two-argument 'ref', with the package name first: 'my_dbt_project' or 'mypkg'

Remove the unique tests, then parse again (this time successfully):

$ dbt --no-partial-parse parse
14:11:23  Running with dbt=1.6.0
14:11:24  Registered adapter: postgres=1.6.0
14:11:24  Performance info: /Users/jerco/dev/scratch/testy/target/perf_info.json

Environment

- OS: macOS Ventura 13.4.1
- Python: 3.10.11
- dbt: 1.6.0

Which database adapter are you using with dbt?

any

Additional Context

I believe this is a bug in v1.6, insofar as it falls under the intended scope of:

• [CT-2472] Allow duplicate model names across packages #7446

And was missed by the implementation in:

• Allow duplicate refable node names across packages #7374

[jtcohen6]

I'm seeing this bug coming up more frequently, because of a change related to the dbt Core v1.6 ←→ MetricFlow integration. each project/package that defines semantic_models and metrics also needs to define a model named metricflow_time_spine. This leads to multiple installations of metricflow_time_spine (from packages + root project), and if any of those packages defines a test on metricflow_time_spine (e.g.), it raises this error message.