fix: close issue #1863 Fix Cython CUDA stream pointer conversion

Convert Python stream pointer integers through uintptr_t before casting
to cudaStream_t. This prevents Cython from treating the int object
address as the CUDA stream handle when using Resources(stream=stream.ptr)
or MultiGpuResources(stream=stream.ptr).

Signed-off-by: yihong0618 <zouzou0208@gmail.com>

Author: yihong0618

python/cuvs/cuvs/common/mg_resources.pyx

@@ -1,12 +1,13 @@
 #
-# SPDX-FileCopyrightText: Copyright (c) 2025, NVIDIA CORPORATION.
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026, NVIDIA CORPORATION.
 # SPDX-License-Identifier: Apache-2.0
 #
 # cython: language_level=3
 
-from cuda.bindings.cyruntime cimport cudaStream_t
+from libc.stdint cimport uintptr_t
 
 from cuvs.common.c_api cimport (
+    cudaStream_t,
     cuvsMultiGpuResourcesCreate,
     cuvsMultiGpuResourcesCreateWithDeviceIds,
     cuvsMultiGpuResourcesDestroy,
@@ -84,11 +85,12 @@ cdef class MultiGpuResources:
         else:
             check_cuvs(cuvsMultiGpuResourcesCreate(&self.c_obj))
 
-        if stream:
-            check_cuvs(cuvsStreamSet(self.c_obj, <cudaStream_t>stream))
+        if stream is not None:
+            check_cuvs(cuvsStreamSet(
+                self.c_obj, <cudaStream_t><uintptr_t>stream))
 
     def sync(self):
-        check_cuvs(cuvsStreamSync(self.c_obj))
+            check_cuvs(cuvsStreamSync(self.c_obj))
 
     def set_memory_pool(self, percent_of_free_memory):
         """

python/cuvs/cuvs/common/resources.pyx

@@ -1,14 +1,15 @@
 #
-# SPDX-FileCopyrightText: Copyright (c) 2024, NVIDIA CORPORATION.
+# SPDX-FileCopyrightText: Copyright (c) 2024-2026, NVIDIA CORPORATION.
 # SPDX-License-Identifier: Apache-2.0
 #
 # cython: language_level=3
 
 import functools
 
-from cuda.bindings.cyruntime cimport cudaStream_t
+from libc.stdint cimport uintptr_t
 
 from cuvs.common.c_api cimport (
+    cudaStream_t,
     cuvsResources_t,
     cuvsResourcesCreate,
     cuvsResourcesDestroy,
@@ -54,8 +55,8 @@ cdef class Resources:
 
     def __cinit__(self, stream=None):
         check_cuvs(cuvsResourcesCreate(&self.c_obj))
-        if stream:
-            check_cuvs(cuvsStreamSet(self.c_obj, <cudaStream_t>stream))
+        if stream is not None:
+            check_cuvs(cuvsStreamSet(self.c_obj, <cudaStream_t><uintptr_t>stream))
 
     def sync(self):
         check_cuvs(cuvsStreamSync(self.c_obj))

python/cuvs/cuvs/tests/test_resources.py

@@ -0,0 +1,17 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION.
+# SPDX-License-Identifier: Apache-2.0
+
+import gc
+
+import cupy as cp
+import cuvs.common.resources as resources_mod
+
+from cuvs.common import Resources
+
+
+def test_resources_syncs_cupy_stream_pointer():
+    # gh-issue: 1836 should not segfault when syncing a stream pointer from cupy
+    stream = cp.cuda.Stream()
+    resources = Resources(stream=stream.ptr)
+
+    resources.sync()