[Bug] Bug: YAML parser misapplies inherited tests when using list-merge anchors with overrides

[gracemalirBP]

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 using a YAML anchor for a list of columns and then using the <<: merge key to inherit that list in a model's configuration, the parser incorrectly applies inherited tests. Specifically, a test belonging to one column in the anchor is misapplied to a different column (often the first column in the list or a column being overridden).

Expected Behavior

I am expecting all tests to be inherited from the defined anchor and then the overridden test to run

Steps To Reproduce

Create a schema.yml file with the following content:

YAML

version: 2

x-anchors:
MINIMAL_COLUMNS: &MINIMAL_COLUMNS
- name: TEST
- name: ID
description: "Base ID column."
- name: CONTEXT_STORE
description: "Base store column."
tests:
- accepted_values:
values: ['UK', 'US']

models:

• name: stg_all_events
  columns:

  Inherit the list

  • <<: *MINIMAL_COLUMNS

  Override the ID column

  • name: ID
    tests:
    • not_null
    • unique
      Run the command: dbt test -s stg_all_events

Expected behavior
The test run should produce three tests applied to their correct columns:

accepted_values on CONTEXT_STORE

not_null on ID

unique on ID

Actual behavior
The test run produces three tests, but the accepted_values test is incorrectly applied to the TEST column (the first column in the anchor) instead of the CONTEXT_STORE column. The following test output is generated:

1 of 3 START test accepted_values_stg_all_events_TEST__UK__US
2 of 3 START test not_null_stg_all_events_ID
3 of 3 START test unique_stg_all_events_ID

Relevant log output

Environment

- OS: macOS
- Python: 3.11.10
- dbt: 1.9.3

Which database adapter are you using with dbt?

snowflake

Additional Context

I have also tried

models:

• name: stg_all_events
  columns:

  Inherit the list

  • <<: *MINIMAL_COLUMNS
  • name: ID
    data_tests:
    • not_null
    • unique
  • name: CONTEXT_STORE
    tests:
    • accepted_values:
      values: ['UK', 'US']

with the hope that it would override the bug but this results in the same tests as before (that were incorrect) plus the correct store test