feast-dev · ntkathole · Mar 6, 2026 · Feb 21, 2026 · Feb 21, 2026 · Mar 4, 2026
@@ -160,8 +160,10 @@ driver_stats_source = FileSource(
 # three feature column. Here we define a Feature View that will allow us to serve this
 # data to our model online.
 driver_stats_fv = FeatureView(
-    # The unique name of this feature view. Two feature views in a single
-    # project cannot have the same name
+# The unique name of this feature view. Two feature views in a single
+# project cannot have the same name, and names must be unique across
+# all feature view types (regular, stream, on-demand) to avoid conflicts
+# during `feast apply`.
     name="driver_hourly_stats",
     entities=[driver],
     ttl=timedelta(days=1),

@@ -411,10 +411,32 @@ def __init__(self, entity_type: type):
 
 class ConflictingFeatureViewNames(FeastError):
     # TODO: print file location of conflicting feature views
-    def __init__(self, feature_view_name: str):
-        super().__init__(
-            f"The feature view name: {feature_view_name} refers to feature views of different types."
-        )
+    def __init__(
+        self,
+        feature_view_name: str,
+        existing_type: Optional[str] = None,
+        new_type: Optional[str] = None,
+    ):
+        if existing_type and new_type:
+            if existing_type == new_type:
+                # Same-type duplicate
+                super().__init__(
+                    f"Multiple {existing_type}s with name '{feature_view_name}' found. "
+                    f"Feature view names must be case-insensitively unique. "
+                    f"It may be necessary to ignore certain files in your feature "
+                    f"repository by using a .feastignore file."
+                )
+            else:
+                # Cross-type conflict
+                super().__init__(
+                    f"Feature view name '{feature_view_name}' is already used by a {existing_type}. "
+                    f"Cannot register a {new_type} with the same name. "
+                    f"Feature view names must be unique across FeatureView, StreamFeatureView, and OnDemandFeatureView."
+                )
+        else:
+            super().__init__(
+                f"The feature view name: {feature_view_name} refers to feature views of different types."
+            )
 
 
 class FeastInvalidInfraObjectType(FeastError):

@@ -58,6 +58,7 @@
 from feast.dqm.errors import ValidationFailed
 from feast.entity import Entity
 from feast.errors import (
+    ConflictingFeatureViewNames,
     DataFrameSerializationError,
     DataSourceRepeatNamesException,
     FeatureViewNotFoundException,
@@ -3255,18 +3256,25 @@ def _print_materialization_log(
 
 
 def _validate_feature_views(feature_views: List[BaseFeatureView]):
-    """Verify feature views have case-insensitively unique names"""
-    fv_names = set()
+    """Verify feature views have case-insensitively unique names across all types.
+
+    This validates that no two feature views (of any type: FeatureView,
+    StreamFeatureView, OnDemandFeatureView) share the same case-insensitive name.
+    This is critical because get_online_features uses get_any_feature_view which
+    resolves names in a fixed order, potentially returning the wrong feature view.
+    """
+    fv_by_name: Dict[str, BaseFeatureView] = {}
     for fv in feature_views:
         case_insensitive_fv_name = fv.name.lower()
-        if case_insensitive_fv_name in fv_names:
-            raise ValueError(
-                f"More than one feature view with name {case_insensitive_fv_name} found. "
-                f"Please ensure that all feature view names are case-insensitively unique. "
-                f"It may be necessary to ignore certain files in your feature repository by using a .feastignore file."
+        if case_insensitive_fv_name in fv_by_name:
+            existing_fv = fv_by_name[case_insensitive_fv_name]
+            raise ConflictingFeatureViewNames(
+                fv.name,
+                existing_type=type(existing_fv).__name__,
+                new_type=type(fv).__name__,
             )
         else:
-            fv_names.add(case_insensitive_fv_name)
+            fv_by_name[case_insensitive_fv_name] = fv
 
 
 def _validate_data_sources(data_sources: List[DataSource]):

@@ -24,6 +24,10 @@
 from feast.base_feature_view import BaseFeatureView
 from feast.data_source import DataSource
 from feast.entity import Entity
+from feast.errors import (
+    ConflictingFeatureViewNames,
+    FeatureViewNotFoundException,
+)
 from feast.feature_service import FeatureService
 from feast.feature_view import FeatureView
 from feast.infra.infra_object import Infra
@@ -263,6 +267,61 @@ def apply_feature_view(
         """
         raise NotImplementedError
 
+    def _ensure_feature_view_name_is_unique(
+        self,
+        feature_view: BaseFeatureView,
+        project: str,
+        allow_cache: bool = False,
+    ):
+        """
+        Validates that no feature view name conflict exists across feature view types.
+        Raises ConflictingFeatureViewNames if a different type already uses the name.
+
+        This is a defense-in-depth check for direct apply_feature_view() calls.
+        The primary validation happens in _validate_all_feature_views() during feast plan/apply.
+        """
+        name = feature_view.name
+        new_type = type(feature_view).__name__
+
+        def _check_conflict(getter, not_found_exc, existing_type: str):
+            try:
+                getter(name, project, allow_cache=allow_cache)
+                raise ConflictingFeatureViewNames(name, existing_type, new_type)
+            except not_found_exc:
+                pass
+
+        # Check StreamFeatureView before FeatureView since StreamFeatureView is a subclass
+        # Note: All getters raise FeatureViewNotFoundException (not type-specific exceptions)
+        if isinstance(feature_view, StreamFeatureView):
+            _check_conflict(
+                self.get_feature_view, FeatureViewNotFoundException, "FeatureView"
+            )
+            _check_conflict(
+                self.get_on_demand_feature_view,
+                FeatureViewNotFoundException,
+                "OnDemandFeatureView",
+            )
+        elif isinstance(feature_view, FeatureView):
+            _check_conflict(
+                self.get_stream_feature_view,
+                FeatureViewNotFoundException,
+                "StreamFeatureView",
+            )
+            _check_conflict(
+                self.get_on_demand_feature_view,
+                FeatureViewNotFoundException,
+                "OnDemandFeatureView",
+            )
+        elif isinstance(feature_view, OnDemandFeatureView):
+            _check_conflict(
+                self.get_feature_view, FeatureViewNotFoundException, "FeatureView"
+            )
+            _check_conflict(
+                self.get_stream_feature_view,
+                FeatureViewNotFoundException,
+                "StreamFeatureView",
+            )
+
     @abstractmethod
     def delete_feature_view(self, name: str, project: str, commit: bool = True):
         """

@@ -578,6 +578,7 @@ def apply_data_source(
     def apply_feature_view(
         self, feature_view: BaseFeatureView, project: str, commit: bool = True
     ):
+        self._ensure_feature_view_name_is_unique(feature_view, project)
         fv_table = self._infer_fv_table(feature_view)
 
         return self._apply_object(

@@ -14,15 +14,23 @@
 from datetime import timedelta
 from tempfile import mkstemp
 
+import pandas as pd
 import pytest
 from pytest_lazyfixture import lazy_fixture
 
+from feast import FileSource
+from feast.data_format import AvroFormat
+from feast.data_source import KafkaSource
 from feast.entity import Entity
-from feast.feature_store import FeatureStore
+from feast.errors import ConflictingFeatureViewNames
+from feast.feature_store import FeatureStore, _validate_feature_views
 from feast.feature_view import FeatureView
+from feast.field import Field
 from feast.infra.online_stores.sqlite import SqliteOnlineStoreConfig
+from feast.on_demand_feature_view import on_demand_feature_view
 from feast.repo_config import RepoConfig
-from feast.types import Float64, Int64, String
+from feast.stream_feature_view import StreamFeatureView
+from feast.types import Float32, Float64, Int64, String
 from tests.utils.data_source_test_creator import prep_file_source
 
 
@@ -75,3 +83,146 @@ def feature_store_with_local_registry():
             entity_key_serialization_version=3,
         )
     )
+
+
+@pytest.mark.integration
+def test_validate_feature_views_cross_type_conflict():
+    """
+    Test that _validate_feature_views() catches cross-type name conflicts.
+
+    This is a unit test for the validation that happens during feast plan/apply.
+    The validation must catch conflicts across FeatureView, StreamFeatureView,
+    and OnDemandFeatureView to prevent silent data correctness bugs in
+    get_online_features (which uses fixed-order lookup).
+
+    See: https://github.com/feast-dev/feast/issues/5995
+    """
+    # Create a simple entity
+    entity = Entity(name="driver_entity", join_keys=["test_key"])
+
+    # Create a regular FeatureView
+    file_source = FileSource(name="my_file_source", path="test.parquet")
+    feature_view = FeatureView(
+        name="my_feature_view",
+        entities=[entity],
+        schema=[Field(name="feature1", dtype=Float32)],
+        source=file_source,
+    )
+
+    # Create a StreamFeatureView with the SAME name
+    stream_source = KafkaSource(
+        name="kafka",
+        timestamp_field="event_timestamp",
+        kafka_bootstrap_servers="",
+        message_format=AvroFormat(""),
+        topic="topic",
+        batch_source=file_source,
+        watermark_delay_threshold=timedelta(days=1),
+    )
+    stream_feature_view = StreamFeatureView(
+        name="my_feature_view",  # Same name as FeatureView!
+        entities=[entity],
+        ttl=timedelta(days=30),
+        schema=[Field(name="feature1", dtype=Float32)],
+        source=stream_source,
+    )
+
+    # Validate should raise ConflictingFeatureViewNames
+    with pytest.raises(ConflictingFeatureViewNames) as exc_info:
+        _validate_feature_views([feature_view, stream_feature_view])
+
+    # Verify error message contains type information
+    error_message = str(exc_info.value)
+    assert "my_feature_view" in error_message
+    assert "FeatureView" in error_message
+    assert "StreamFeatureView" in error_message
+
+
+def test_validate_feature_views_same_type_conflict():
+    """
+    Test that _validate_feature_views() also catches same-type name conflicts
+    with a proper error message indicating duplicate FeatureViews.
+    """
+    # Create a simple entity
+    entity = Entity(name="driver_entity", join_keys=["test_key"])
+
+    # Create two FeatureViews with the same name
+    file_source = FileSource(name="my_file_source", path="test.parquet")
+    fv1 = FeatureView(
+        name="duplicate_fv",
+        entities=[entity],
+        schema=[Field(name="feature1", dtype=Float32)],
+        source=file_source,
+    )
+    fv2 = FeatureView(
+        name="duplicate_fv",  # Same name!
+        entities=[entity],
+        schema=[Field(name="feature2", dtype=Float32)],
+        source=file_source,
+    )
+
+    # Validate should raise ConflictingFeatureViewNames
+    with pytest.raises(ConflictingFeatureViewNames) as exc_info:
+        _validate_feature_views([fv1, fv2])
+
+    # Verify error message indicates same-type duplicate
+    error_message = str(exc_info.value)
+    assert "duplicate_fv" in error_message
+    assert "Multiple FeatureViews" in error_message
+    assert "case-insensitively unique" in error_message
+
+
+def test_validate_feature_views_case_insensitive():
+    """
+    Test that _validate_feature_views() catches case-insensitive conflicts.
+    """
+    entity = Entity(name="driver_entity", join_keys=["test_key"])
+    file_source = FileSource(name="my_file_source", path="test.parquet")
+
+    fv1 = FeatureView(
+        name="MyFeatureView",
+        entities=[entity],
+        schema=[Field(name="feature1", dtype=Float32)],
+        source=file_source,
+    )
+    fv2 = FeatureView(
+        name="myfeatureview",  # Same name, different case!
+        entities=[entity],
+        schema=[Field(name="feature2", dtype=Float32)],
+        source=file_source,
+    )
+
+    # Validate should raise ConflictingFeatureViewNames (case-insensitive)
+    with pytest.raises(ConflictingFeatureViewNames):
+        _validate_feature_views([fv1, fv2])
+
+
+def test_validate_feature_views_odfv_conflict():
+    """
+    Test that _validate_feature_views() catches OnDemandFeatureView name conflicts.
+    """
+    entity = Entity(name="driver_entity", join_keys=["test_key"])
+    file_source = FileSource(name="my_file_source", path="test.parquet")
+
+    fv = FeatureView(
+        name="shared_name",
+        entities=[entity],
+        schema=[Field(name="feature1", dtype=Float32)],
+        source=file_source,
+    )
+
+    @on_demand_feature_view(
+        sources=[fv],
+        schema=[Field(name="output", dtype=Float32)],
+    )
+    def shared_name(inputs: pd.DataFrame) -> pd.DataFrame:
+        return pd.DataFrame({"output": inputs["feature1"] * 2})
+
+    # Validate should raise ConflictingFeatureViewNames
+    with pytest.raises(ConflictingFeatureViewNames) as exc_info:
+        _validate_feature_views([fv, shared_name])
+
+    error_message = str(exc_info.value)
+    assert "shared_name" in error_message
+    assert "FeatureView" in error_message
+    assert "OnDemandFeatureView" in error_message