Merge pull request #15271 from seberg/splitup-faster-argparsing

ENH: Optimize and cleanup ufunc calls and ufunc CheckOverrides

doc/release/upcoming_changes/15271.compatibility.rst

@@ -0,0 +1,31 @@
+Error type changes in universal functions
+-----------------------------------------
+The universal functions may now raise different errors
+on invalid input in some cases.
+The main changes should be that a ``RuntimeError`` was
+replaced with a more fitting ``TypeError``.
+When multiple errors were present in the same call,
+NumPy may now raise a different one.
+
+
+``__array_ufunc__`` argument validation
+---------------------------------------
+NumPy will now partially validate arguments before calling
+``__array_ufunc__``.  Previously, it was possible to pass
+on invalid arguments (such as a non-existing keyword
+argument) when dispatch was known to occur.
+
+
+``__array_ufunc__`` and additional positional arguments
+-------------------------------------------------------
+Previously, all positionally passed arguments were checked for
+``__array_ufunc__`` support.  In the case of ``reduce``,
+``accumulate``, and ``reduceat`` all arguments may be passed by
+position.  This means that when they were passed by
+position, they could previously have been asked to handle
+the ufunc call via ``__array_ufunc__``.
+Since this depended on the way the arguments were passed
+(by position or by keyword), NumPy will now only dispatch
+on the input and output array.
+For example, NumPy will never dispatch on the ``where`` array
+in a reduction such as ``np.add.reduce``.

numpy/core/include/numpy/ufuncobject.h

@@ -194,7 +194,11 @@ typedef struct _tagPyUFuncObject {
          * but this was never implemented. (This is also why the above
          * selector is called the "legacy" selector.)
          */
+    #if PY_VERSION_HEX >= 0x03080000
+        vectorcallfunc vectorcall;
+    #else
         void *reserved2;
+    #endif
         /*
          * A function which returns a masked inner loop for the ufunc.
          */