fix(indexes): ensure CCI created on final relation, not __dbt_tmp (#578)

[mopthe]

Fixes #578 - Creating nonclustered indexes in a SQL Server materialized table was resulting in an orphaned clustered columnstore index.

The key fix: index names are now derived from the final relation name (with __dbt_tmp / __dbt_backup suffixes stripped). This ensures:

• A second run produces an identical index name (idempotent)
• CCIs are not orphaned after intermediate relations are renamed
• No conflicts when drop_all_indexes_on_table runs

Add comprehensive integration and unit tests covering incremental runs, INCLUDE columns, quoted identifiers, and idempotence.

[Copilot]

Pull request overview

This PR fixes SQL Server index-macro behavior to prevent “orphaned” clustered columnstore index (CCI) naming during materializations that involve intermediate __dbt_tmp / __dbt_backup relations, by deriving index names from the final relation name and improving identifier quoting. It also adds unit + integration coverage around determinism/idempotence, INCLUDE columns, and quoted identifiers.

Changes:

• Refactors index macros to use deterministic index naming derived from the final relation identifier (suffix-stripped) and improved quoting.
• Updates the CCI creation macro to avoid __dbt_tmp / __dbt_backup leaking into the index name.
• Adds comprehensive unit tests for macro rendering plus live SQL Server integration tests validating idempotence, INCLUDE semantics, quoted identifiers, and the orphaned-CCI regression.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
dbt/include/sqlserver/macros/adapters/indexes.sql	Adds quoting/qualification helpers and refactors index/CCI macros to produce deterministic names and safer SQL.
dbt/include/sqlserver/macros/relations/table/create.sql	Updates the inline comment to document the new “final relation name” index naming behavior.
tests/unit/adapters/mssql/test_indexes.py	Adds Jinja-rendered unit tests for quoting, suffix-stripping, deterministic names, and emitted SQL shapes.
tests/functional/adapter/mssql/test_index_macros.py	Adds integration tests against live SQL Server for incremental stability, INCLUDE columns, quoted identifiers, and orphaned-CCI regression.

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[mopthe]

Migration Note: Orphaned Indexes

This release prevents orphaned CCI indexes from being created on intermediate __dbt_tmp tables across all materializations.

• table materialization: No action required. The table is fully recreated on each run, so any pre-existing orphaned indexes are dropped automatically.
• incremental materialization: Orphaned indexes created by prior versions persist and must be cleaned up manually (see below).

Cleaning up orphaned indexes

-- Identify orphaned CCI indexes
SELECT
    name AS index_name,
    OBJECT_SCHEMA_NAME(object_id) AS schema_name,
    OBJECT_NAME(object_id) AS table_name
FROM sys.indexes
WHERE name LIKE '%__dbt_tmp%cci';

-- Drop each one
DROP INDEX [index_name] ON [schema_name].[table_name];

[Benjamin-Knight]

I think you have converted the file endings because the file is showing a huge number of changes and I don't think there are any there, it makes the pull request difficult to parse.

[mopthe]

@Benjamin-Knight Thanks! Should be readable now.