generate sources: Snowflake quoted lowercase/mixed-case identifiers not preserved in sources.yml

[k0x2e]

Summary

dbt-coves generate sources reads Snowflake metadata for quoted, case-sensitive identifiers correctly (for example, a table created as "my_table"). However, the sources.yml it generates doesn't keep the case and never sets quoting. As a result, the generated source and staging models fail at dbt run.

What works

• Relations come from adapter.list_relations() (dbt_coves/tasks/generate/base.py). dbt-snowflake builds them with quote_policy set to true for database, schema and identifier.
• get_columns_in_relation() therefore runs describe table "DB"."RAW"."my_table" and finds the correct table.
• Column names in the generated staging SQL are quoted with their exact case ("my_col"::varchar as my_col).

What's broken

dbt_coves/templates/source_props.yml:

sources:
  - name: {% if not relation.schema.isupper() and not relation.schema.islower() %}{{ relation.schema }}{% else %}{{ relation.schema.lower() }}{% endif %}
    tables:
      - name: {% if not relation.name.isupper() and not relation.name.islower() %}{{ relation.name }}{% else %}{{ relation.name.lower() }}{% endif %}

1. Case information is lost: MY_TABLE and "my_table" both render as name: my_table.
2. Quoting is never enabled: dbt-snowflake defaults to no quoting, so source('raw', 'my_table') compiles to db.raw.my_table. Snowflake resolves that to MY_TABLE, which fails with "Object does not exist". Mixed-case tables ("MyTable") and lowercase or mixed-case schemas fail the same way.

Steps to reproduce

1. In Snowflake: create table raw."my_table" ("id" int);
2. dbt-coves generate sources --schemas raw --select-relations my_table
3. dbt run -s stg_... → Object 'DB.RAW.MY_TABLE' does not exist or not authorized

Proposed fix

In source_props.yml, emit quoting only when a name isn't all uppercase, so output for standard uppercase identifiers stays the same:

sources:
  - name: raw
    quoting:
      schema: true        # when schema != schema.upper()
    tables:
      - name: my_table
        quoting:
          identifier: true  # when name != name.upper()

Snowflake-only. Other adapters shouldn't be affected.

Related

get_metadata_map_key (dbt_coves/tasks/generate/base.py) lowercases every key part, so columns "MyCol" and MYCOL in the same relation map to the same metadata entry.

[github-actions]

Triage of #649

Type: bug report (Snowflake, generate sources).

Repro info: Fairly good. It has concrete SQL, the command, and the resulting error. It is missing the dbt-coves, dbt-core and dbt-snowflake versions, and whether QUOTED_IDENTIFIERS_IGNORE_CASE is set. There is no traceback or full log, but the error message is quoted.

Static check (code matches the report):

• dbt_coves/templates/source_props.yml:4 and :9 emit relation.schema and relation.name as-is only when the name is mixed-case. All-lowercase and all-uppercase names are lowercased. So "my_table" and MY_TABLE both render as my_table, as described.
• The template never emits a quoting: block, so quoting depends on dbt's defaults. On dbt-snowflake that means unquoted.
• get_metadata_map_key (dbt_coves/tasks/generate/base.py:162-165) lowercases every key part, so "MyCol" and MYCOL collide, as noted in the "Related" section.
• Relations come from adapter.list_relations() (base.py:125). I did not check how dbt-snowflake sets the relation's quote_policy, so that part of the report is unverified.

Note on the proposed fix: Lowercasing an all-uppercase name and emitting quoting only when the name is not all-uppercase looks compatible with existing output. Two things to check:

• The template's mixed-case branch already preserves case, so mixed-case names probably fail only because quoting is missing.
• The quoting block must be limited to Snowflake, and the change should be tested for the staging model templates too.

Duplicates: No similar open issues found.

Suggested labels: bug (already applied). Keep triaged: no until a maintainer confirms. Consider priority: low, since this is a Snowflake edge case involving quoted identifiers, but that is the maintainers' call.