Current Behavior

The issue is in sdk/python/feast/infra/registry/registry.py. When multiple projects share the same registry and have data sources with the same name (like the default vals_to_add), the apply_data_source method matches by name only, without filtering by project, causing cross-project overwriting.

Correctly scoped (name + project):

apply_entity (line 349-352):

if (existing_entity_proto.spec.name == entity_proto.spec.name
    and existing_entity_proto.spec.project == project):

apply_feature_service (line 447-451):

if (existing_feature_service_proto.spec.name == feature_service_proto.spec.name
    and existing_feature_service_proto.spec.project == project):

apply_feature_view (line 779-781):

if (existing_feature_view_proto.spec.name == feature_view_proto.spec.name
    and existing_feature_view_proto.spec.project == project):

BUG - name-only matching, no project filter:

apply_data_source (line 396-397):

        for idx, existing_data_source_proto in enumerate(registry.data_sources):
            if existing_data_source_proto.name == data_source.name:

delete_data_source (line 426):

if data_source_proto.name == name:

Steps to reproduce

• feast apply for project test registers vals_to_add with project=test
• feast apply for project test1 iterates all data_sources, finds vals_to_add from project test (matched by name only, no project check)
• The equality check fails (they differ - at minimum different internal state), so it deletes the test version and adds a new one with project=test1

Specifications

• Version: latest

Possible Solution

The fix would be to add the project filter to both apply_data_source and delete_data_source:

# apply_data_source fix (line 397):
if existing_data_source_proto.name == data_source.name and existing_data_source_proto.project == project:

# delete_data_source fix (line 426):
if data_source_proto.name == name and data_source_proto.project == project: