3 - Avoid recreating snapshot_by_name in evaluator

[cmgoffena13]

File: sqlmesh/core/snapshot/evaluator.py
Function: promote , _promote_snapshot
Lines: 267 - 330 , 1253 - 1285

Issue with _promote_snapshot

In _promote_snapshot we are passed the snapshots, which is keyed by snapshot_id. The function needs to key by snapshot_name though, so we keep recreating:

snapshot_by_name = {s.name: s for s in (snapshots or {}).values()}
render_kwargs["snapshots"] = snapshot_by_name

We should just create this once in promote before we pass it in.

        # Fetch the view data objects for the promoted snapshots to get them cached
        self._get_virtual_data_objects(target_snapshots, environment_naming_info)

       snapshot_by_name = {s.name: s for s in (snapshots or {}).values()}    <------NEW

        deployability_index = deployability_index or DeployabilityIndex.all_deployable()
        with self.concurrent_context():
            concurrent_apply_to_snapshots(
                target_snapshots,
                lambda s: self._promote_snapshot(
                    s,
                    start=start,
                    end=end,
                    execution_time=execution_time,
                    snapshots=snapshots,
                    snapshots_by_name=snapshots_by_name,    <-------- NEW
                    table_mapping=table_mapping,
                    environment_naming_info=environment_naming_info,
                    deployability_index=deployability_index,  # type: ignore
                    on_complete=on_complete,
                ),
                self.ddl_concurrent_tasks,
            )

Roughly. I would also evaluate if we can remove the snapshots input to self._promote_snapshot. Maybe snapshots_by_name fulfills all the functions downstream.