From 01f33cdce0b783e721e55b779c0713b7415d105f Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Tue, 24 Mar 2026 16:47:01 -0700
Subject: [PATCH 01/10] build: use cuda.pathfinder.get_cuda_path_or_home in
 build hooks

Pin cuda-pathfinder>=1.5 in both build-system.requires and
project.dependencies.

Made-with: Cursor
---
 cuda_bindings/build_hooks.py        | 32 ++++++++++++++++++++++++-----
 cuda_bindings/pyproject.toml        |  3 ++-
 cuda_core/build_hooks.py            | 32 ++++++++++++++++++++++++-----
 cuda_core/pyproject.toml            |  3 ++-
 cuda_core/tests/test_build_hooks.py |  7 ++++++-
 5 files changed, 64 insertions(+), 13 deletions(-)

diff --git a/cuda_bindings/build_hooks.py b/cuda_bindings/build_hooks.py
index a48aa0f0e9..1bd2b37424 100644
--- a/cuda_bindings/build_hooks.py
+++ b/cuda_bindings/build_hooks.py
@@ -33,13 +33,35 @@
 _extensions = None
 
 
+# Please keep in sync with the copy in cuda_core/build_hooks.py.
+def _import_get_cuda_path_or_home():
+    """Import get_cuda_path_or_home, working around PEP 517 namespace shadowing.
+
+    In isolated build environments, backend-path=["."] causes the ``cuda``
+    namespace package to resolve to only the project's ``cuda/`` directory,
+    hiding ``cuda.pathfinder`` installed in the build-env's site-packages.
+    Fix by replacing ``cuda.__path__`` with a plain list that includes the
+    site-packages ``cuda/`` directory.
+    """
+    try:
+        import cuda.pathfinder
+    except ModuleNotFoundError:
+        import cuda
+
+        for p in sys.path:
+            sp_cuda = os.path.join(p, "cuda")
+            if os.path.isdir(os.path.join(sp_cuda, "pathfinder")):
+                cuda.__path__ = list(cuda.__path__) + [sp_cuda]
+                break
+        import cuda.pathfinder
+
+    return cuda.pathfinder.get_cuda_path_or_home
+
+
 @functools.cache
 def _get_cuda_path() -> str:
-    # Not using cuda.pathfinder.get_cuda_path_or_home() here because this
-    # build backend runs in an isolated venv where the cuda namespace package
-    # from backend-path shadows the installed cuda-pathfinder. See #1803 for
-    # a workaround to apply after cuda-pathfinder >= 1.5 is released.
-    cuda_path = os.environ.get("CUDA_PATH", os.environ.get("CUDA_HOME"))
+    get_cuda_path_or_home = _import_get_cuda_path_or_home()
+    cuda_path = get_cuda_path_or_home()
     if not cuda_path:
         raise RuntimeError("Environment variable CUDA_PATH or CUDA_HOME is not set")
     print("CUDA path:", cuda_path)
diff --git a/cuda_bindings/pyproject.toml b/cuda_bindings/pyproject.toml
index 96cfb4dd07..9a4f189815 100644
--- a/cuda_bindings/pyproject.toml
+++ b/cuda_bindings/pyproject.toml
@@ -6,6 +6,7 @@ requires = [
     "setuptools_scm[simple]>=8",
     "cython>=3.2,<3.3",
     "pyclibrary>=0.1.7",
+    "cuda-pathfinder>=1.5",
 ]
 build-backend = "build_hooks"
 backend-path = ["."]
@@ -31,7 +32,7 @@ classifiers = [
     "Environment :: GPU :: NVIDIA CUDA",
 ]
 dynamic = ["version", "readme"]
-dependencies = ["cuda-pathfinder >=1.4.2"]
+dependencies = ["cuda-pathfinder >=1.5"]
 
 [project.optional-dependencies]
 all = [
diff --git a/cuda_core/build_hooks.py b/cuda_core/build_hooks.py
index b368b02759..912848317a 100644
--- a/cuda_core/build_hooks.py
+++ b/cuda_core/build_hooks.py
@@ -28,13 +28,35 @@
 COMPILE_FOR_COVERAGE = bool(int(os.environ.get("CUDA_PYTHON_COVERAGE", "0")))
 
 
+# Please keep in sync with the copy in cuda_bindings/build_hooks.py.
+def _import_get_cuda_path_or_home():
+    """Import get_cuda_path_or_home, working around PEP 517 namespace shadowing.
+
+    In isolated build environments, backend-path=["."] causes the ``cuda``
+    namespace package to resolve to only the project's ``cuda/`` directory,
+    hiding ``cuda.pathfinder`` installed in the build-env's site-packages.
+    Fix by replacing ``cuda.__path__`` with a plain list that includes the
+    site-packages ``cuda/`` directory.
+    """
+    try:
+        import cuda.pathfinder
+    except ModuleNotFoundError:
+        import cuda
+
+        for p in sys.path:
+            sp_cuda = os.path.join(p, "cuda")
+            if os.path.isdir(os.path.join(sp_cuda, "pathfinder")):
+                cuda.__path__ = list(cuda.__path__) + [sp_cuda]
+                break
+        import cuda.pathfinder
+
+    return cuda.pathfinder.get_cuda_path_or_home
+
+
 @functools.cache
 def _get_cuda_path() -> str:
-    # Not using cuda.pathfinder.get_cuda_path_or_home() here because this
-    # build backend runs in an isolated venv where the cuda namespace package
-    # from backend-path shadows the installed cuda-pathfinder. See #1803 for
-    # a workaround to apply after cuda-pathfinder >= 1.5 is released.
-    cuda_path = os.environ.get("CUDA_PATH", os.environ.get("CUDA_HOME"))
+    get_cuda_path_or_home = _import_get_cuda_path_or_home()
+    cuda_path = get_cuda_path_or_home()
     if not cuda_path:
         raise RuntimeError("Environment variable CUDA_PATH or CUDA_HOME is not set")
     print("CUDA path:", cuda_path)
diff --git a/cuda_core/pyproject.toml b/cuda_core/pyproject.toml
index 107c2ffb92..dc418342b5 100644
--- a/cuda_core/pyproject.toml
+++ b/cuda_core/pyproject.toml
@@ -7,6 +7,7 @@ requires = [
     "setuptools>=80",
     "setuptools-scm[simple]>=8",
     "Cython>=3.2,<3.3",
+    "cuda-pathfinder>=1.5"
 ]
 build-backend = "build_hooks"
 backend-path = ["."]
@@ -47,7 +48,7 @@ classifiers = [
     "Environment :: GPU :: NVIDIA CUDA :: 13",
 ]
 dependencies = [
-    "cuda-pathfinder >=1.4.2",
+    "cuda-pathfinder >=1.5",
     "numpy",
 ]
 
diff --git a/cuda_core/tests/test_build_hooks.py b/cuda_core/tests/test_build_hooks.py
index b298e7a977..121ed1be05 100644
--- a/cuda_core/tests/test_build_hooks.py
+++ b/cuda_core/tests/test_build_hooks.py
@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright (c) 2024-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-FileCopyrightText: Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 """Tests for build_hooks.py build infrastructure.
@@ -24,6 +24,8 @@
 
 import pytest
 
+from cuda.pathfinder import get_cuda_path_or_home
+
 # build_hooks.py imports Cython and setuptools at the top level, so skip if not available
 pytest.importorskip("Cython")
 pytest.importorskip("setuptools")
@@ -68,6 +70,7 @@ def _check_version_detection(
 
         build_hooks._get_cuda_path.cache_clear()
         build_hooks._determine_cuda_major_version.cache_clear()
+        get_cuda_path_or_home.cache_clear()
 
         mock_env = {
             k: v
@@ -92,6 +95,7 @@ def test_env_var_override(self, version):
         """CUDA_CORE_BUILD_MAJOR env var override works with various versions."""
         build_hooks._get_cuda_path.cache_clear()
         build_hooks._determine_cuda_major_version.cache_clear()
+        get_cuda_path_or_home.cache_clear()
         with mock.patch.dict(os.environ, {"CUDA_CORE_BUILD_MAJOR": version}, clear=False):
             result = build_hooks._determine_cuda_major_version()
             assert result == version
@@ -125,6 +129,7 @@ def test_missing_cuda_path_raises_error(self):
         """RuntimeError is raised when CUDA_PATH/CUDA_HOME not set and no env var override."""
         build_hooks._get_cuda_path.cache_clear()
         build_hooks._determine_cuda_major_version.cache_clear()
+        get_cuda_path_or_home.cache_clear()
         with (
             mock.patch.dict(os.environ, {}, clear=True),
             pytest.raises(RuntimeError, match="CUDA_PATH or CUDA_HOME"),

From 0fc45970483957817d5e7c78086afc68027cf605 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Tue, 24 Mar 2026 16:53:24 -0700
Subject: [PATCH 02/10] chore: update stale pixi package version to 1.5.0

The previous 1.3.4a0 was a stale value that could confuse someone.

Made-with: Cursor
---
 cuda_pathfinder/pixi.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cuda_pathfinder/pixi.toml b/cuda_pathfinder/pixi.toml
index 0d780290b6..961450699c 100644
--- a/cuda_pathfinder/pixi.toml
+++ b/cuda_pathfinder/pixi.toml
@@ -36,7 +36,7 @@ cu12 = { features = ["cu12", "test"], solve-group = "cu12" }
 # TODO: check if these can be extracted from pyproject.toml
 [package]
 name = "cuda-pathfinder"
-version = "1.3.4a0"
+version = "1.5.0"
 
 [package.build]
 backend = { name = "pixi-build-python", version = "*" }

From 3d422de019926291c9107598918393b4c8584525 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Wed, 25 Mar 2026 11:18:42 -0700
Subject: [PATCH 03/10] build: raise actionable error when cuda-pathfinder not
 found on sys.path

Made-with: Cursor
---
 cuda_bindings/build_hooks.py | 5 +++++
 cuda_core/build_hooks.py     | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/cuda_bindings/build_hooks.py b/cuda_bindings/build_hooks.py
index 1bd2b37424..9e592431ee 100644
--- a/cuda_bindings/build_hooks.py
+++ b/cuda_bindings/build_hooks.py
@@ -53,6 +53,11 @@ def _import_get_cuda_path_or_home():
             if os.path.isdir(os.path.join(sp_cuda, "pathfinder")):
                 cuda.__path__ = list(cuda.__path__) + [sp_cuda]
                 break
+        else:
+            raise ModuleNotFoundError(
+                "cuda-pathfinder is not installed in the build environment. "
+                "Ensure 'cuda-pathfinder>=1.5' is in build-system.requires."
+            )
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home
diff --git a/cuda_core/build_hooks.py b/cuda_core/build_hooks.py
index 912848317a..d5f2bb43a2 100644
--- a/cuda_core/build_hooks.py
+++ b/cuda_core/build_hooks.py
@@ -48,6 +48,11 @@ def _import_get_cuda_path_or_home():
             if os.path.isdir(os.path.join(sp_cuda, "pathfinder")):
                 cuda.__path__ = list(cuda.__path__) + [sp_cuda]
                 break
+        else:
+            raise ModuleNotFoundError(
+                "cuda-pathfinder is not installed in the build environment. "
+                "Ensure 'cuda-pathfinder>=1.5' is in build-system.requires."
+            )
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home

From 6892ae01391c92f30a28699f1e710120451b8037 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Wed, 25 Mar 2026 12:37:22 -0700
Subject: [PATCH 04/10] build: replace inline docstring with reference to issue
 #1824

Made-with: Cursor
---
 cuda_bindings/build_hooks.py | 6 +-----
 cuda_core/build_hooks.py     | 6 +-----
 2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/cuda_bindings/build_hooks.py b/cuda_bindings/build_hooks.py
index 9e592431ee..9c6710a264 100644
--- a/cuda_bindings/build_hooks.py
+++ b/cuda_bindings/build_hooks.py
@@ -37,11 +37,7 @@
 def _import_get_cuda_path_or_home():
     """Import get_cuda_path_or_home, working around PEP 517 namespace shadowing.
 
-    In isolated build environments, backend-path=["."] causes the ``cuda``
-    namespace package to resolve to only the project's ``cuda/`` directory,
-    hiding ``cuda.pathfinder`` installed in the build-env's site-packages.
-    Fix by replacing ``cuda.__path__`` with a plain list that includes the
-    site-packages ``cuda/`` directory.
+    See https://github.com/NVIDIA/cuda-python/issues/1824 for why this helper is needed.
     """
     try:
         import cuda.pathfinder
diff --git a/cuda_core/build_hooks.py b/cuda_core/build_hooks.py
index d5f2bb43a2..ce77de3c17 100644
--- a/cuda_core/build_hooks.py
+++ b/cuda_core/build_hooks.py
@@ -32,11 +32,7 @@
 def _import_get_cuda_path_or_home():
     """Import get_cuda_path_or_home, working around PEP 517 namespace shadowing.
 
-    In isolated build environments, backend-path=["."] causes the ``cuda``
-    namespace package to resolve to only the project's ``cuda/`` directory,
-    hiding ``cuda.pathfinder`` installed in the build-env's site-packages.
-    Fix by replacing ``cuda.__path__`` with a plain list that includes the
-    site-packages ``cuda/`` directory.
+    See https://github.com/NVIDIA/cuda-python/issues/1824 for why this helper is needed.
     """
     try:
         import cuda.pathfinder

From b779d0d99a90a155b8fd9a242c13f5b4d6d872fb Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Tue, 31 Mar 2026 08:41:32 -0700
Subject: [PATCH 05/10] build: narrow except to only catch
 cuda.pathfinder-not-found

Made-with: Cursor
---
 cuda_bindings/build_hooks.py | 4 +++-
 cuda_core/build_hooks.py     | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/cuda_bindings/build_hooks.py b/cuda_bindings/build_hooks.py
index 9c6710a264..398d0d7f62 100644
--- a/cuda_bindings/build_hooks.py
+++ b/cuda_bindings/build_hooks.py
@@ -41,7 +41,9 @@ def _import_get_cuda_path_or_home():
     """
     try:
         import cuda.pathfinder
-    except ModuleNotFoundError:
+    except ModuleNotFoundError as exc:
+        if exc.name != "cuda.pathfinder":
+            raise
         import cuda
 
         for p in sys.path:
diff --git a/cuda_core/build_hooks.py b/cuda_core/build_hooks.py
index ce77de3c17..6b51d02b30 100644
--- a/cuda_core/build_hooks.py
+++ b/cuda_core/build_hooks.py
@@ -36,7 +36,9 @@ def _import_get_cuda_path_or_home():
     """
     try:
         import cuda.pathfinder
-    except ModuleNotFoundError:
+    except ModuleNotFoundError as exc:
+        if exc.name != "cuda.pathfinder":
+            raise
         import cuda
 
         for p in sys.path:

From 6facaa5272c289e3d93576a446567871a4ca732c Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Tue, 31 Mar 2026 08:52:40 -0700
Subject: [PATCH 06/10] build: use importlib.metadata to locate cuda-pathfinder
 instead of scanning sys.path

Made-with: Cursor
---
 cuda_bindings/build_hooks.py | 18 +++++++++++-------
 cuda_core/build_hooks.py     | 18 +++++++++++-------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/cuda_bindings/build_hooks.py b/cuda_bindings/build_hooks.py
index 398d0d7f62..07c370c5ee 100644
--- a/cuda_bindings/build_hooks.py
+++ b/cuda_bindings/build_hooks.py
@@ -44,18 +44,22 @@ def _import_get_cuda_path_or_home():
     except ModuleNotFoundError as exc:
         if exc.name != "cuda.pathfinder":
             raise
+        from importlib.metadata import PackageNotFoundError, distribution
+        from pathlib import Path
+
         import cuda
 
-        for p in sys.path:
-            sp_cuda = os.path.join(p, "cuda")
-            if os.path.isdir(os.path.join(sp_cuda, "pathfinder")):
-                cuda.__path__ = list(cuda.__path__) + [sp_cuda]
-                break
-        else:
+        try:
+            dist = distribution("cuda-pathfinder")
+        except PackageNotFoundError:
             raise ModuleNotFoundError(
                 "cuda-pathfinder is not installed in the build environment. "
                 "Ensure 'cuda-pathfinder>=1.5' is in build-system.requires."
-            )
+            ) from None
+        site_cuda = str(dist.locate_file(Path("cuda")))
+        cuda_paths = list(cuda.__path__)
+        if site_cuda not in cuda_paths:
+            cuda.__path__ = cuda_paths + [site_cuda]
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home
diff --git a/cuda_core/build_hooks.py b/cuda_core/build_hooks.py
index 6b51d02b30..3483f7d041 100644
--- a/cuda_core/build_hooks.py
+++ b/cuda_core/build_hooks.py
@@ -39,18 +39,22 @@ def _import_get_cuda_path_or_home():
     except ModuleNotFoundError as exc:
         if exc.name != "cuda.pathfinder":
             raise
+        from importlib.metadata import PackageNotFoundError, distribution
+        from pathlib import Path
+
         import cuda
 
-        for p in sys.path:
-            sp_cuda = os.path.join(p, "cuda")
-            if os.path.isdir(os.path.join(sp_cuda, "pathfinder")):
-                cuda.__path__ = list(cuda.__path__) + [sp_cuda]
-                break
-        else:
+        try:
+            dist = distribution("cuda-pathfinder")
+        except PackageNotFoundError:
             raise ModuleNotFoundError(
                 "cuda-pathfinder is not installed in the build environment. "
                 "Ensure 'cuda-pathfinder>=1.5' is in build-system.requires."
-            )
+            ) from None
+        site_cuda = str(dist.locate_file(Path("cuda")))
+        cuda_paths = list(cuda.__path__)
+        if site_cuda not in cuda_paths:
+            cuda.__path__ = cuda_paths + [site_cuda]
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home

From f1ef076d5063a16c5224fbacb185aaeac4f0ab5f Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Tue, 31 Mar 2026 09:40:54 -0700
Subject: [PATCH 07/10] build: produce actionable error when cuda namespace is
 entirely absent

Made-with: Cursor
---
 cuda_bindings/build_hooks.py | 6 +++---
 cuda_core/build_hooks.py     | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/cuda_bindings/build_hooks.py b/cuda_bindings/build_hooks.py
index 07c370c5ee..81a112e022 100644
--- a/cuda_bindings/build_hooks.py
+++ b/cuda_bindings/build_hooks.py
@@ -42,13 +42,11 @@ def _import_get_cuda_path_or_home():
     try:
         import cuda.pathfinder
     except ModuleNotFoundError as exc:
-        if exc.name != "cuda.pathfinder":
+        if exc.name not in ("cuda", "cuda.pathfinder"):
             raise
         from importlib.metadata import PackageNotFoundError, distribution
         from pathlib import Path
 
-        import cuda
-
         try:
             dist = distribution("cuda-pathfinder")
         except PackageNotFoundError:
@@ -56,6 +54,8 @@ def _import_get_cuda_path_or_home():
                 "cuda-pathfinder is not installed in the build environment. "
                 "Ensure 'cuda-pathfinder>=1.5' is in build-system.requires."
             ) from None
+        import cuda
+
         site_cuda = str(dist.locate_file(Path("cuda")))
         cuda_paths = list(cuda.__path__)
         if site_cuda not in cuda_paths:
diff --git a/cuda_core/build_hooks.py b/cuda_core/build_hooks.py
index 3483f7d041..fcca21ad95 100644
--- a/cuda_core/build_hooks.py
+++ b/cuda_core/build_hooks.py
@@ -37,13 +37,11 @@ def _import_get_cuda_path_or_home():
     try:
         import cuda.pathfinder
     except ModuleNotFoundError as exc:
-        if exc.name != "cuda.pathfinder":
+        if exc.name not in ("cuda", "cuda.pathfinder"):
             raise
         from importlib.metadata import PackageNotFoundError, distribution
         from pathlib import Path
 
-        import cuda
-
         try:
             dist = distribution("cuda-pathfinder")
         except PackageNotFoundError:
@@ -51,6 +49,8 @@ def _import_get_cuda_path_or_home():
                 "cuda-pathfinder is not installed in the build environment. "
                 "Ensure 'cuda-pathfinder>=1.5' is in build-system.requires."
             ) from None
+        import cuda
+
         site_cuda = str(dist.locate_file(Path("cuda")))
         cuda_paths = list(cuda.__path__)
         if site_cuda not in cuda_paths:

From 3cb0313301d2b3ce1dd822542d8fced87546cbd5 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Tue, 31 Mar 2026 10:02:48 -0700
Subject: [PATCH 08/10] build: diagnostic for importlib.metadata locate_file in
 PEP 517 builds

Made-with: Cursor
---
 cuda_bindings/build_hooks.py | 19 ++++++++++++++++++-
 cuda_core/build_hooks.py     | 19 ++++++++++++++++++-
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/cuda_bindings/build_hooks.py b/cuda_bindings/build_hooks.py
index 81a112e022..1a59777aeb 100644
--- a/cuda_bindings/build_hooks.py
+++ b/cuda_bindings/build_hooks.py
@@ -56,10 +56,27 @@ def _import_get_cuda_path_or_home():
             ) from None
         import cuda
 
-        site_cuda = str(dist.locate_file(Path("cuda")))
+        locate_result = str(dist.locate_file(Path("cuda")))
+        print(f"[diag] dist._path: {dist._path}", flush=True)
+        print(f"[diag] dist._path.parent: {dist._path.parent}", flush=True)
+        print(f"[diag] locate_file('cuda'): {locate_result}", flush=True)
+        print(f"[diag] locate_file exists: {os.path.isdir(locate_result)}", flush=True)
+        print(
+            f"[diag] locate_file/pathfinder exists: {os.path.isdir(os.path.join(locate_result, 'pathfinder'))}",
+            flush=True,
+        )
+        print(f"[diag] cuda.__path__ (before): {cuda.__path__}", flush=True)
+        print("[diag] sys.path:", flush=True)
+        for p in sys.path:
+            sp_cuda = os.path.join(p, "cuda")
+            has_pf = os.path.isdir(os.path.join(sp_cuda, "pathfinder"))
+            print(f"[diag]   {p}  ->  cuda/pathfinder exists: {has_pf}", flush=True)
+
+        site_cuda = locate_result
         cuda_paths = list(cuda.__path__)
         if site_cuda not in cuda_paths:
             cuda.__path__ = cuda_paths + [site_cuda]
+        print(f"[diag] cuda.__path__ (after): {cuda.__path__}", flush=True)
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home
diff --git a/cuda_core/build_hooks.py b/cuda_core/build_hooks.py
index fcca21ad95..6b4a117faa 100644
--- a/cuda_core/build_hooks.py
+++ b/cuda_core/build_hooks.py
@@ -51,10 +51,27 @@ def _import_get_cuda_path_or_home():
             ) from None
         import cuda
 
-        site_cuda = str(dist.locate_file(Path("cuda")))
+        locate_result = str(dist.locate_file(Path("cuda")))
+        print(f"[diag] dist._path: {dist._path}", flush=True)
+        print(f"[diag] dist._path.parent: {dist._path.parent}", flush=True)
+        print(f"[diag] locate_file('cuda'): {locate_result}", flush=True)
+        print(f"[diag] locate_file exists: {os.path.isdir(locate_result)}", flush=True)
+        print(
+            f"[diag] locate_file/pathfinder exists: {os.path.isdir(os.path.join(locate_result, 'pathfinder'))}",
+            flush=True,
+        )
+        print(f"[diag] cuda.__path__ (before): {cuda.__path__}", flush=True)
+        print("[diag] sys.path:", flush=True)
+        for p in sys.path:
+            sp_cuda = os.path.join(p, "cuda")
+            has_pf = os.path.isdir(os.path.join(sp_cuda, "pathfinder"))
+            print(f"[diag]   {p}  ->  cuda/pathfinder exists: {has_pf}", flush=True)
+
+        site_cuda = locate_result
         cuda_paths = list(cuda.__path__)
         if site_cuda not in cuda_paths:
             cuda.__path__ = cuda_paths + [site_cuda]
+        print(f"[diag] cuda.__path__ (after): {cuda.__path__}", flush=True)
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home

From a9995acafe50dc42d359054acf4cb0244eee5176 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Tue, 31 Mar 2026 12:14:23 -0700
Subject: [PATCH 09/10] Revert "build: diagnostic for importlib.metadata
 locate_file in PEP 517 builds"

This reverts commit 3cb0313301d2b3ce1dd822542d8fced87546cbd5.
---
 cuda_bindings/build_hooks.py | 19 +------------------
 cuda_core/build_hooks.py     | 19 +------------------
 2 files changed, 2 insertions(+), 36 deletions(-)

diff --git a/cuda_bindings/build_hooks.py b/cuda_bindings/build_hooks.py
index 1a59777aeb..81a112e022 100644
--- a/cuda_bindings/build_hooks.py
+++ b/cuda_bindings/build_hooks.py
@@ -56,27 +56,10 @@ def _import_get_cuda_path_or_home():
             ) from None
         import cuda
 
-        locate_result = str(dist.locate_file(Path("cuda")))
-        print(f"[diag] dist._path: {dist._path}", flush=True)
-        print(f"[diag] dist._path.parent: {dist._path.parent}", flush=True)
-        print(f"[diag] locate_file('cuda'): {locate_result}", flush=True)
-        print(f"[diag] locate_file exists: {os.path.isdir(locate_result)}", flush=True)
-        print(
-            f"[diag] locate_file/pathfinder exists: {os.path.isdir(os.path.join(locate_result, 'pathfinder'))}",
-            flush=True,
-        )
-        print(f"[diag] cuda.__path__ (before): {cuda.__path__}", flush=True)
-        print("[diag] sys.path:", flush=True)
-        for p in sys.path:
-            sp_cuda = os.path.join(p, "cuda")
-            has_pf = os.path.isdir(os.path.join(sp_cuda, "pathfinder"))
-            print(f"[diag]   {p}  ->  cuda/pathfinder exists: {has_pf}", flush=True)
-
-        site_cuda = locate_result
+        site_cuda = str(dist.locate_file(Path("cuda")))
         cuda_paths = list(cuda.__path__)
         if site_cuda not in cuda_paths:
             cuda.__path__ = cuda_paths + [site_cuda]
-        print(f"[diag] cuda.__path__ (after): {cuda.__path__}", flush=True)
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home
diff --git a/cuda_core/build_hooks.py b/cuda_core/build_hooks.py
index 6b4a117faa..fcca21ad95 100644
--- a/cuda_core/build_hooks.py
+++ b/cuda_core/build_hooks.py
@@ -51,27 +51,10 @@ def _import_get_cuda_path_or_home():
             ) from None
         import cuda
 
-        locate_result = str(dist.locate_file(Path("cuda")))
-        print(f"[diag] dist._path: {dist._path}", flush=True)
-        print(f"[diag] dist._path.parent: {dist._path.parent}", flush=True)
-        print(f"[diag] locate_file('cuda'): {locate_result}", flush=True)
-        print(f"[diag] locate_file exists: {os.path.isdir(locate_result)}", flush=True)
-        print(
-            f"[diag] locate_file/pathfinder exists: {os.path.isdir(os.path.join(locate_result, 'pathfinder'))}",
-            flush=True,
-        )
-        print(f"[diag] cuda.__path__ (before): {cuda.__path__}", flush=True)
-        print("[diag] sys.path:", flush=True)
-        for p in sys.path:
-            sp_cuda = os.path.join(p, "cuda")
-            has_pf = os.path.isdir(os.path.join(sp_cuda, "pathfinder"))
-            print(f"[diag]   {p}  ->  cuda/pathfinder exists: {has_pf}", flush=True)
-
-        site_cuda = locate_result
+        site_cuda = str(dist.locate_file(Path("cuda")))
         cuda_paths = list(cuda.__path__)
         if site_cuda not in cuda_paths:
             cuda.__path__ = cuda_paths + [site_cuda]
-        print(f"[diag] cuda.__path__ (after): {cuda.__path__}", flush=True)
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home

From cb5ffbb136ea6559fbe62ec085327116e58bda11 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Tue, 31 Mar 2026 12:18:11 -0700
Subject: [PATCH 10/10] build: revert to sys.path scan, importlib.metadata
 finds wrong dist-info

See https://github.com/NVIDIA/cuda-python/pull/1817#discussion_r3017709196
See https://github.com/NVIDIA/cuda-python/pull/1817#discussion_r3017746666

Made-with: Cursor
---
 cuda_bindings/build_hooks.py | 23 +++++++++++------------
 cuda_core/build_hooks.py     | 23 +++++++++++------------
 2 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/cuda_bindings/build_hooks.py b/cuda_bindings/build_hooks.py
index 81a112e022..b08b0d24d8 100644
--- a/cuda_bindings/build_hooks.py
+++ b/cuda_bindings/build_hooks.py
@@ -44,22 +44,21 @@ def _import_get_cuda_path_or_home():
     except ModuleNotFoundError as exc:
         if exc.name not in ("cuda", "cuda.pathfinder"):
             raise
-        from importlib.metadata import PackageNotFoundError, distribution
-        from pathlib import Path
-
         try:
-            dist = distribution("cuda-pathfinder")
-        except PackageNotFoundError:
+            import cuda
+        except ModuleNotFoundError:
+            cuda = None
+
+        for p in sys.path:
+            sp_cuda = os.path.join(p, "cuda")
+            if os.path.isdir(os.path.join(sp_cuda, "pathfinder")):
+                cuda.__path__ = list(cuda.__path__) + [sp_cuda]
+                break
+        else:
             raise ModuleNotFoundError(
                 "cuda-pathfinder is not installed in the build environment. "
                 "Ensure 'cuda-pathfinder>=1.5' is in build-system.requires."
-            ) from None
-        import cuda
-
-        site_cuda = str(dist.locate_file(Path("cuda")))
-        cuda_paths = list(cuda.__path__)
-        if site_cuda not in cuda_paths:
-            cuda.__path__ = cuda_paths + [site_cuda]
+            )
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home
diff --git a/cuda_core/build_hooks.py b/cuda_core/build_hooks.py
index fcca21ad95..491879c2ab 100644
--- a/cuda_core/build_hooks.py
+++ b/cuda_core/build_hooks.py
@@ -39,22 +39,21 @@ def _import_get_cuda_path_or_home():
     except ModuleNotFoundError as exc:
         if exc.name not in ("cuda", "cuda.pathfinder"):
             raise
-        from importlib.metadata import PackageNotFoundError, distribution
-        from pathlib import Path
-
         try:
-            dist = distribution("cuda-pathfinder")
-        except PackageNotFoundError:
+            import cuda
+        except ModuleNotFoundError:
+            cuda = None
+
+        for p in sys.path:
+            sp_cuda = os.path.join(p, "cuda")
+            if os.path.isdir(os.path.join(sp_cuda, "pathfinder")):
+                cuda.__path__ = list(cuda.__path__) + [sp_cuda]
+                break
+        else:
             raise ModuleNotFoundError(
                 "cuda-pathfinder is not installed in the build environment. "
                 "Ensure 'cuda-pathfinder>=1.5' is in build-system.requires."
-            ) from None
-        import cuda
-
-        site_cuda = str(dist.locate_file(Path("cuda")))
-        cuda_paths = list(cuda.__path__)
-        if site_cuda not in cuda_paths:
-            cuda.__path__ = cuda_paths + [site_cuda]
+            )
         import cuda.pathfinder
 
     return cuda.pathfinder.get_cuda_path_or_home