fix: Avoid importing feast.feature_store at mcp_server import time#6634
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ntkathole merged 1 commit intoJul 23, 2026
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #6634 +/- ##
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- Coverage 45.75% 45.74% -0.01%
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Files 414 414
Lines 49701 49698 -3
Branches 7087 7087
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- Hits 22739 22736 -3
Misses 25377 25377
Partials 1585 1585
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ntkathole
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Jul 23, 2026
mcp_server used a module-level `from feast.feature_store import FeatureStore` solely for a type annotation on add_mcp_support_to_app. Because the feast.infra.mcp_servers package __init__ eagerly imports mcp_server, importing the package pulled in the entire feature_store import graph. Under parallel unit-test collection (pytest -n) this intermittently raced with an in-progress feature_store import and failed collection of test_mcp_server.py with `KeyError: 'feast.infra.mcp_servers.mcp_server'`. Move the import under TYPE_CHECKING and use a forward reference, so importing mcp_server no longer triggers the feature_store graph. Public API and the annotation are unchanged. Signed-off-by: Larry Singleton <166439969+larrysingleton007@users.noreply.github.com>
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What this PR does / why we need it:
feast/infra/mcp_servers/mcp_server.pyimportedfeast.feature_store.FeatureStoreat module load, but used it only for a type annotation onadd_mcp_support_to_app. Because thefeast.infra.mcp_serverspackage__init__eagerly importsmcp_server, importing the package pulled the entirefeature_storeimport graph in as a side effect.Under parallel unit-test collection (
pytest -n), that heavy import intermittently raced with an in-progressfeature_storeimport and failed collection oftests/unit/infra/feature_servers/test_mcp_server.pywithKeyError: 'feast.infra.mcp_servers.mcp_server'. The tests pass in isolation, so it shows up as a flakyunit-test-pythonfailure.Moving the import under
TYPE_CHECKINGwith a forward-reference annotation removesfeature_storefrommcp_server's module-load path, so importingmcp_serverno longer triggers that graph. Public API and the annotation are unchanged.Which issue(s) this PR fixes:
Fixes #6633
Checks
git commit -s)Testing Strategy
test_mcp_server.pypasses (23), andfeast.infra.mcp_serversstill exposesadd_mcp_support_to_appandMcpFeatureServerConfig. ruff and mypy clean.Misc
Release note: NONE.
As an outside contributor I can't apply labels, so a maintainer will need to add
kind/bugand runok-to-test.