From eb85684feb0505694e66365ba9f4d10a409f8f0b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <34657725+jeremiedbb@users.noreply.github.com>
Date: Wed, 11 Oct 2023 11:43:47 +0200
Subject: [PATCH] MAINT Follow cython performance hints (#27521)

---
 .../_middle_term_computer.pyx.tp                   |  2 +-
 .../preprocessing/_csr_polynomial_expansion.pyx    |  2 +-
 sklearn/tree/_splitter.pyx                         |  2 +-
 sklearn/tree/_utils.pxd                            |  2 +-
 sklearn/tree/_utils.pyx                            | 14 ++++++--------
 5 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/sklearn/metrics/_pairwise_distances_reduction/_middle_term_computer.pyx.tp b/sklearn/metrics/_pairwise_distances_reduction/_middle_term_computer.pyx.tp
index f2d89ed65909c..bfe465394c4d2 100644
--- a/sklearn/metrics/_pairwise_distances_reduction/_middle_term_computer.pyx.tp
+++ b/sklearn/metrics/_pairwise_distances_reduction/_middle_term_computer.pyx.tp
@@ -82,7 +82,7 @@ cdef void _middle_term_sparse_dense_{{name_suffix}}(
     intp_t Y_end,
     bint c_ordered_middle_term,
     float64_t * dist_middle_terms,
-) nogil:
+) noexcept nogil:
     # This routine assumes that dist_middle_terms is a pointer to the first element
     # of a buffer filled with zeros of length at least equal to n_X × n_Y, conceptually
     # representing a 2-d C-ordered of F-ordered array.
diff --git a/sklearn/preprocessing/_csr_polynomial_expansion.pyx b/sklearn/preprocessing/_csr_polynomial_expansion.pyx
index 90f81c0399a6e..017af83f035b2 100644
--- a/sklearn/preprocessing/_csr_polynomial_expansion.pyx
+++ b/sklearn/preprocessing/_csr_polynomial_expansion.pyx
@@ -166,7 +166,7 @@ cpdef void _csr_polynomial_expansion(
     INDEX_B_t[:] result_indptr,     # OUT
     FLAG_t interaction_only,
     FLAG_t degree
-) nogil:
+):
     """
     Perform a second or third degree polynomial or interaction expansion on a
     compressed sparse row (CSR) matrix. The method used only takes products of
diff --git a/sklearn/tree/_splitter.pyx b/sklearn/tree/_splitter.pyx
index a9d3a169ec84a..81cd61ed22631 100644
--- a/sklearn/tree/_splitter.pyx
+++ b/sklearn/tree/_splitter.pyx
@@ -263,7 +263,7 @@ cdef inline void shift_missing_values_to_left_if_required(
     SplitRecord* best,
     intp_t[::1] samples,
     intp_t end,
-) nogil:
+) noexcept nogil:
     cdef intp_t i, p, current_end
     # The partitioner partitions the data such that the missing values are in
     # samples[-n_missing:] for the criterion to consume. If the missing values
diff --git a/sklearn/tree/_utils.pxd b/sklearn/tree/_utils.pxd
index 4167230bfbf4d..b59d18879ca94 100644
--- a/sklearn/tree/_utils.pxd
+++ b/sklearn/tree/_utils.pxd
@@ -39,7 +39,7 @@ ctypedef fused realloc_ptr:
     (Cell*)
     (Node**)
 
-cdef realloc_ptr safe_realloc(realloc_ptr* p, size_t nelems) except * nogil
+cdef int safe_realloc(realloc_ptr* p, size_t nelems) except -1 nogil
 
 
 cdef cnp.ndarray sizet_ptr_to_ndarray(intp_t* data, intp_t size)
diff --git a/sklearn/tree/_utils.pyx b/sklearn/tree/_utils.pyx
index 3c0c312b25fbe..b6115d4f21d18 100644
--- a/sklearn/tree/_utils.pyx
+++ b/sklearn/tree/_utils.pyx
@@ -22,22 +22,20 @@ from ..utils._random cimport our_rand_r
 # Helper functions
 # =============================================================================
 
-cdef realloc_ptr safe_realloc(realloc_ptr* p, size_t nelems) except * nogil:
+cdef int safe_realloc(realloc_ptr* p, size_t nelems) except -1 nogil:
     # sizeof(realloc_ptr[0]) would be more like idiomatic C, but causes Cython
     # 0.20.1 to crash.
     cdef size_t nbytes = nelems * sizeof(p[0][0])
     if nbytes / sizeof(p[0][0]) != nelems:
         # Overflow in the multiplication
-        with gil:
-            raise MemoryError("could not allocate (%d * %d) bytes"
-                              % (nelems, sizeof(p[0][0])))
+        raise MemoryError(f"could not allocate ({nelems} * {sizeof(p[0][0])}) bytes")
+
     cdef realloc_ptr tmp = <realloc_ptr>realloc(p[0], nbytes)
     if tmp == NULL:
-        with gil:
-            raise MemoryError("could not allocate %d bytes" % nbytes)
+        raise MemoryError(f"could not allocate {nbytes} bytes")
 
     p[0] = tmp
-    return tmp  # for convenience
+    return 0
 
 
 def _realloc_test():
@@ -111,7 +109,7 @@ cdef class WeightedPQueue:
         or 0 otherwise.
         """
         self.array_ptr = 0
-        # Since safe_realloc can raise MemoryError, use `except *`
+        # Since safe_realloc can raise MemoryError, use `except -1`
         safe_realloc(&self.array_, self.capacity)
         return 0