feat(stores)!: use backend storage references instead of configs

tests/unit/core/test_persistence_config.py

@@ -0,0 +1,82 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+import pytest
+from pydantic import ValidationError
+
+from llama_stack.core.datatypes import (
+    InferenceStoreReference,
+    PersistenceConfig,
+    StoreReference,
+    StoresConfig,
+)
+from llama_stack.providers.utils.kvstore.config import SqliteKVStoreConfig
+from llama_stack.providers.utils.sqlstore.sqlstore import (
+    PostgresSqlStoreConfig,
+    SqliteSqlStoreConfig,
+)
+
+
+def test_backend_reference_validation_catches_missing_backend():
+    """Critical: Catch user typos in backend references before runtime."""
+    with pytest.raises(ValidationError, match="not defined in persistence.backends"):
+        PersistenceConfig(
+            backends={
+                "default": SqliteSqlStoreConfig(db_path="/tmp/store.db"),
+            },
+            stores=StoresConfig(
+                metadata=StoreReference(backend="typo_backend"),  # User typo
+            ),
+        )
+
+
+def test_backend_reference_validation_accepts_valid_config():
+    """Valid config should parse without errors."""
+    config = PersistenceConfig(
+        backends={
+            "default": SqliteSqlStoreConfig(db_path="/tmp/store.db"),
+        },
+        stores=StoresConfig(
+            metadata=StoreReference(backend="default"),
+            inference=InferenceStoreReference(backend="default"),
+        ),
+    )
+    assert config.stores.metadata.backend == "default"
+    assert config.stores.inference.backend == "default"
+
+
+def test_multiple_stores_can_share_same_backend():
+    """Core use case: metadata and inference both use 'default' backend."""
+    config = PersistenceConfig(
+        backends={
+            "default": SqliteSqlStoreConfig(db_path="/tmp/shared.db"),
+        },
+        stores=StoresConfig(
+            metadata=StoreReference(backend="default", namespace="metadata"),
+            inference=InferenceStoreReference(backend="default"),
+            conversations=StoreReference(backend="default"),
+        ),
+    )
+    # All reference the same backend
+    assert config.stores.metadata.backend == "default"
+    assert config.stores.inference.backend == "default"
+    assert config.stores.conversations.backend == "default"
+
+
+def test_mixed_backend_types_allowed():
+    """Should support KVStore and SqlStore backends simultaneously."""
+    config = PersistenceConfig(
+        backends={
+            "kvstore": SqliteKVStoreConfig(db_path="/tmp/kv.db"),
+            "sqlstore": PostgresSqlStoreConfig(user="test", password="test", host="localhost", db="test"),
+        },
+        stores=StoresConfig(
+            metadata=StoreReference(backend="kvstore"),
+            inference=InferenceStoreReference(backend="sqlstore"),
+        ),
+    )
+    assert isinstance(config.backends["kvstore"], SqliteKVStoreConfig)
+    assert isinstance(config.backends["sqlstore"], PostgresSqlStoreConfig)