Optimize C extension hot paths#353
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jensens merged 5 commits intozopefoundation:masterfrom Feb 27, 2026
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Eliminates PyTuple_New + N x PyTuple_SET_ITEM + Py_DECREF on every cache-valid lookup call. Also enables early exit on first mismatch.
Direct struct field access avoids the generic truth protocol dispatch (type slot lookup -> sq_length or nb_bool) for the name parameter.
… a tuple Use PyTuple_CheckExact fast path to avoid allocating a copy when the required argument is already a tuple (the common case from Python callers).
Use a pre-interned static string with PyDict_GetItem instead of PyDict_GetItemString with a C literal (which creates a temporary Python string on each call). Also replace direct ob_type struct access with the Py_TYPE() macro for free-threaded compatibility.
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tseaver
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https://status.coveralls.io/ is down and blocks the CI |
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@jensens I just subscribed to the issue at https://status.coveralls.io/ |
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Summary
Four targeted optimizations to the C extension hot paths, reducing
overhead in adapter lookups and interface calls.
Changes
_verify(): in-place generation comparison — Compare registrygeneration counters directly against the stored snapshot instead of
allocating a temporary tuple via
_generations_tuple()on everycache-valid lookup. Enables early exit on first mismatch.
_getcache():PyUnicode_GET_LENGTHinstead ofPyObject_IsTrue—Direct struct field access instead of generic truth protocol dispatch.
_lookup/_lookupAll/_subscriptions:PyTuple_CheckExactfast path —Skip
PySequence_Tupleallocation whenrequiredis already a tuple(the common case from Python callers).
IB__call__: intern_CALL_CUSTOM_ADAPTstring +Py_TYPEmacro —Pre-interned static string with
PyDict_GetIteminstead ofPyDict_GetItemString(which creates a temporary Python string eachcall). Also replaces direct
ob_typeaccess withPy_TYPE()forfree-threaded Python compatibility.
Benchmark (Python 3.14.0, Linux, best of 3 runs)
lb.lookup(...))IFoo(foo)(call + adapt)providedBy(foo)