diff --git a/docker/pythonpath_dev/superset_config.py b/docker/pythonpath_dev/superset_config.py
index 108305cf900..ce7f1998708 100644
--- a/docker/pythonpath_dev/superset_config.py
+++ b/docker/pythonpath_dev/superset_config.py
@@ -105,7 +105,13 @@ class CeleryConfig:
 
 CELERY_CONFIG = CeleryConfig
 
-FEATURE_FLAGS = {"ALERT_REPORTS": True, "DATASET_FOLDERS": True}
+FEATURE_FLAGS = {
+    "ALERT_REPORTS": True,
+    "DATASET_FOLDERS": True,
+    "ENABLE_EXTENSIONS": True,
+    "SEMANTIC_LAYERS": True,
+}
+EXTENSIONS_PATH = "/app/docker/extensions"
 ALERT_REPORTS_NOTIFICATION_DRY_RUN = True
 WEBDRIVER_BASEURL = f"http://superset_app{os.environ.get('SUPERSET_APP_ROOT', '/')}/"  # When using docker compose baseurl should be http://superset_nginx{ENV{BASEPATH}}/  # noqa: E501
 # The base URL for the email report hyperlinks.
diff --git a/superset-frontend/package-lock.json b/superset-frontend/package-lock.json
index f7ea57d8f44..11fe2949d37 100644
--- a/superset-frontend/package-lock.json
+++ b/superset-frontend/package-lock.json
@@ -4076,6 +4076,18 @@
         "url": "https://github.com/sponsors/ayuhito"
       }
     },
+    "node_modules/@googleapis/sheets": {
+      "version": "13.0.1",
+      "resolved": "https://registry.npmjs.org/@googleapis/sheets/-/sheets-13.0.1.tgz",
+      "integrity": "sha512-XTYObncN5Rqexc0uITZIN9OWTEyE/ZR2S6c7wAniqHe2oGXW9gcHR9f9hQwPMHFUTHjH7Jkj8SLdt0O0u37y2A==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "googleapis-common": "^8.0.0"
+      },
+      "engines": {
+        "node": ">=12.0.0"
+      }
+    },
     "node_modules/@great-expectations/jsonforms-antd-renderers": {
       "version": "2.2.11",
       "resolved": "https://registry.npmjs.org/@great-expectations/jsonforms-antd-renderers/-/jsonforms-antd-renderers-2.2.11.tgz",
@@ -4096,18 +4108,6 @@
         "react": "^17 || ^18"
       }
     },
-    "node_modules/@googleapis/sheets": {
-      "version": "13.0.1",
-      "resolved": "https://registry.npmjs.org/@googleapis/sheets/-/sheets-13.0.1.tgz",
-      "integrity": "sha512-XTYObncN5Rqexc0uITZIN9OWTEyE/ZR2S6c7wAniqHe2oGXW9gcHR9f9hQwPMHFUTHjH7Jkj8SLdt0O0u37y2A==",
-      "license": "Apache-2.0",
-      "dependencies": {
-        "googleapis-common": "^8.0.0"
-      },
-      "engines": {
-        "node": ">=12.0.0"
-      }
-    },
     "node_modules/@hapi/address": {
       "version": "5.1.1",
       "resolved": "https://registry.npmjs.org/@hapi/address/-/address-5.1.1.tgz",
diff --git a/superset/commands/datasource/list.py b/superset/commands/datasource/list.py
index 50ea765b4c3..caec143994d 100644
--- a/superset/commands/datasource/list.py
+++ b/superset/commands/datasource/list.py
@@ -65,6 +65,9 @@ class GetCombinedDatasourceListCommand(BaseCommand):
         source_type, name_filter, sql_filter, type_filter = self._parse_filters(filters)
         source_type = self._resolve_source_type(source_type, sql_filter, type_filter)
 
+        if source_type == "empty":
+            return {"count": 0, "result": []}
+
         ds_q = DatasourceDAO.build_dataset_query(name_filter, sql_filter)
         sv_q = DatasourceDAO.build_semantic_view_query(name_filter)
 
@@ -108,8 +111,18 @@ class GetCombinedDatasourceListCommand(BaseCommand):
         sql_filter: bool | None,
         type_filter: str | None,
     ) -> str:
-        """Narrow source_type based on access flags, sql filter, and type filter."""
+        """Narrow source_type based on access flags, sql filter, and type filter.
+
+        Returns one of: "database", "semantic_layer", "all", or "empty".
+        "empty" signals that the caller should short-circuit and return no results
+        (used when the user explicitly requests semantic views but lacks access).
+        """
         if not self._can_read_semantic_views:
+            # If the user explicitly asked for semantic views but cannot read them,
+            # return "empty" so the caller yields zero results rather than silently
+            # falling back to the full dataset list.
+            if source_type == "semantic_layer" or type_filter == "semantic_view":
+                return "empty"
             return "database"
         if not self._can_read_datasets:
             return "semantic_layer"
diff --git a/superset/daos/semantic_layer.py b/superset/daos/semantic_layer.py
index 9690a2fa12b..c92745bd119 100644
--- a/superset/daos/semantic_layer.py
+++ b/superset/daos/semantic_layer.py
@@ -22,18 +22,20 @@ from __future__ import annotations
 from typing import Any
 
 from sqlalchemy.exc import StatementError
-
 from superset_core.semantic_layers.daos import (
     AbstractSemanticLayerDAO,
     AbstractSemanticViewDAO,
 )
 
+from superset.daos.base import BaseDAO
 from superset.extensions import db
 from superset.semantic_layers.models import SemanticLayer, SemanticView
 from superset.utils import json
 
 
-class SemanticLayerDAO(AbstractSemanticLayerDAO):
+class SemanticLayerDAO(BaseDAO[SemanticLayer], AbstractSemanticLayerDAO):
+    # SemanticLayer uses uuid as the primary key
+    id_column_name = "uuid"
     """
     Data Access Object for SemanticLayer model.
     """
@@ -112,7 +114,7 @@ class SemanticLayerDAO(AbstractSemanticLayerDAO):
         )
 
 
-class SemanticViewDAO(AbstractSemanticViewDAO):
+class SemanticViewDAO(BaseDAO[SemanticView], AbstractSemanticViewDAO):
     """Data Access Object for SemanticView model."""
 
     model_cls = SemanticView
diff --git a/superset/semantic_layers/api.py b/superset/semantic_layers/api.py
index b5d5bdc6bf2..f161ce53465 100644
--- a/superset/semantic_layers/api.py
+++ b/superset/semantic_layers/api.py
@@ -55,7 +55,7 @@ from superset.commands.semantic_layer.update import (
     UpdateSemanticViewCommand,
 )
 from superset.constants import MODEL_API_RW_METHOD_PERMISSION_MAP
-from superset.daos.semantic_layer import SemanticLayerDAO, SemanticViewDAO
+from superset.daos.semantic_layer import SemanticLayerDAO
 from superset.datasets.schemas import get_delete_ids_schema
 from superset.models.core import Database
 from superset.semantic_layers.models import SemanticLayer, SemanticView
@@ -174,6 +174,11 @@ class SemanticViewRestApi(BaseSupersetModelRestApi):
     class_permission_name = "SemanticView"
     method_permission_name = MODEL_API_RW_METHOD_PERMISSION_MAP
     include_route_methods = {"put", "post", "delete", "bulk_delete"}
+    # SemanticViewRestApi exposes only write endpoints, but can_read must be
+    # declared explicitly so that FAB registers the permission. It is used by
+    # DatasourceRestApi.combined_list to gate access to semantic views in the
+    # combined datasource list.
+    base_permissions = ["can_read", "can_write"]
 
     edit_model_schema = SemanticViewPutSchema()
 
@@ -625,7 +630,7 @@ class SemanticLayerRestApi(BaseSupersetApi):
             )
 
         # Check which views already exist with the same runtime config
-        existing = SemanticViewDAO.find_by_semantic_layer(str(layer.uuid))
+        existing = SemanticLayerDAO.get_semantic_views(str(layer.uuid))
         existing_keys: set[tuple[str, str]] = set()
         for v in existing:
             config = v.configuration
diff --git a/superset/semantic_layers/mapper.py b/superset/semantic_layers/mapper.py
index f2c13865cdf..23dea06124d 100644
--- a/superset/semantic_layers/mapper.py
+++ b/superset/semantic_layers/mapper.py
@@ -291,11 +291,7 @@ def map_query_object(query_object: ValidatedQueryObject) -> list[SemanticQuery]:
 
     metrics = [all_metrics[metric] for metric in (query_object.metrics or [])]
 
-    grain = (
-        _convert_time_grain(query_object.extras["time_grain_sqla"])
-        if "time_grain_sqla" in query_object.extras
-        else None
-    )
+    grain = _convert_time_grain(query_object.extras.get("time_grain_sqla"))
     dimensions = [
         dimension
         for dimension in semantic_view.dimensions
@@ -740,13 +736,17 @@ def _get_group_limit_filters(
     return filters if filters else None
 
 
-def _convert_time_grain(time_grain: str) -> Grain | None:
+def _convert_time_grain(time_grain: str | None) -> Grain | None:
     """
     Convert a time grain string (ISO 8601 duration) to a Grain instance.
+
+    Returns None when ``time_grain`` is None or empty (no grain selected).
     """
+    if not time_grain:
+        return None
     try:
         return Grains.get(time_grain)
-    except (ValueError, isodate.ISO8601Error):
+    except (TypeError, ValueError, isodate.ISO8601Error):
         return None
 
 
diff --git a/tests/unit_tests/semantic_layers/api_test.py b/tests/unit_tests/semantic_layers/api_test.py
index f7acfb47e34..47e8aa24135 100644
--- a/tests/unit_tests/semantic_layers/api_test.py
+++ b/tests/unit_tests/semantic_layers/api_test.py
@@ -1813,8 +1813,7 @@ def test_get_views(
     mock_dao = mocker.patch("superset.semantic_layers.api.SemanticLayerDAO")
     mock_dao.find_by_uuid.return_value = mock_layer
 
-    mock_sv_dao = mocker.patch("superset.semantic_layers.api.SemanticViewDAO")
-    mock_sv_dao.find_by_semantic_layer.return_value = []
+    mock_dao.get_semantic_views.return_value = []
 
     response = client.post(
         f"/api/v1/semantic_layer/{test_uuid}/views",
@@ -1851,8 +1850,7 @@ def test_get_views_with_existing(
     existing_view.name = "Existing View"
     existing_view.configuration = '{"database": "mydb"}'
 
-    mock_sv_dao = mocker.patch("superset.semantic_layers.api.SemanticViewDAO")
-    mock_sv_dao.find_by_semantic_layer.return_value = [existing_view]
+    mock_dao.get_semantic_views.return_value = [existing_view]
 
     response = client.post(
         f"/api/v1/semantic_layer/{test_uuid}/views",
@@ -1932,8 +1930,7 @@ def test_get_views_existing_dict_config(
     existing_view.name = "View X"
     existing_view.configuration = {"key": "val"}  # dict, not string
 
-    mock_sv_dao = mocker.patch("superset.semantic_layers.api.SemanticViewDAO")
-    mock_sv_dao.find_by_semantic_layer.return_value = [existing_view]
+    mock_dao.get_semantic_views.return_value = [existing_view]
 
     response = client.post(
         f"/api/v1/semantic_layer/{test_uuid}/views",