Indirectly caused schema changes result in confusingly reporting direct modifications

[georgesittas]

The mapping_schema model attribute is propagated throughout the DAG after the initial project loading stage. This means that changing the projections of a model may result in updating the mapping_schema of its children. Given that this attribute is used to compute columns_to_types, which is included in the data hash computation, models that are seemingly untouched can be confusingly reported as "directly modified".

This behavior can be easily reproduced using the example project:

$ sqlmesh init duckdb
$ sqlmesh plan --no-prompts --auto-apply
...
$ cat > models/incremental_model.sql  # append '1' to the 'id' column
MODEL (name sqlmesh_example.incremental_model,
  kind INCREMENTAL_BY_TIME_RANGE (
    time_column event_date
  ),
  start '2020-01-01',
  cron '@daily',
  grain (id, event_date)
);

SELECT
  id1,
  item_id,
  event_date,
FROM
  sqlmesh_example.seed_model
WHERE
  event_date BETWEEN @start_date AND @end_date

$ sqlmesh plan  # the full model is confusingly reported as "directly modified"
...
Models:
└── Directly Modified:
    ├── sqlmesh_example.incremental_model
    └── sqlmesh_example.full_model