From 01fafa5b9e1de0f1ab2a9d108cd0fce20ab9568f Mon Sep 17 00:00:00 2001
From: Wenzel Jakob <wenzel.jakob@epfl.ch>
Date: Fri, 24 May 2024 12:17:54 +0200
Subject: [PATCH] added nb::hash wrapper

---
 docs/api_core.rst                | 6 ++++++
 include/nanobind/nb_misc.h       | 7 +++++++
 tests/test_functions.cpp         | 2 ++
 tests/test_functions.py          | 4 ++++
 tests/test_functions_ext.pyi.ref | 2 ++
 5 files changed, 21 insertions(+)

diff --git a/docs/api_core.rst b/docs/api_core.rst
index a61b0571..b4765ead 100644
--- a/docs/api_core.rst
+++ b/docs/api_core.rst
@@ -2744,6 +2744,12 @@ Miscellaneous
 
    Return the ``globals()`` dictionary.
 
+.. cpp:function:: Py_hash_t hash(handle h)
+
+   Hash the given argument like ``hash()`` in pure Python. The type of the
+   return value (``Py_hash_t``) is an implementation-specific signed integer
+   type.
+
 .. cpp:function:: template <typename Source, typename Target> void implicitly_convertible()
 
    Indicate that the type `Source` is implicitly convertible into `Target`
diff --git a/include/nanobind/nb_misc.h b/include/nanobind/nb_misc.h
index 3020f224..6f7cfb77 100644
--- a/include/nanobind/nb_misc.h
+++ b/include/nanobind/nb_misc.h
@@ -46,6 +46,13 @@ inline dict globals() {
     return borrow<dict>(p);
 }
 
+inline Py_hash_t hash(handle h) {
+    Py_hash_t rv = PyObject_Hash(h.ptr());
+    if (rv == -1 && PyErr_Occurred())
+        nanobind::raise_python_error();
+    return rv;
+}
+
 inline bool is_alive() noexcept {
     return detail::is_alive();
 }
diff --git a/tests/test_functions.cpp b/tests/test_functions.cpp
index b62e1e0d..d11ad7e3 100644
--- a/tests/test_functions.cpp
+++ b/tests/test_functions.cpp
@@ -359,4 +359,6 @@ NB_MODULE(test_functions_ext, m) {
 
         return b;
     });
+
+    m.def("hash_it", [](nb::handle h) { return nb::hash(h); });
 }
diff --git a/tests/test_functions.py b/tests/test_functions.py
index e8b8e099..f335e614 100644
--- a/tests/test_functions.py
+++ b/tests/test_functions.py
@@ -591,3 +591,7 @@ def test43_wrappers_dict():
 
 def test43_wrappers_set():
     assert t.test_wrappers_set()
+
+def test44_hash():
+    value = (1, 2, 3)
+    assert t.hash_it(value) == hash(value);
diff --git a/tests/test_functions_ext.pyi.ref b/tests/test_functions_ext.pyi.ref
index 5bb16ecc..45a6701d 100644
--- a/tests/test_functions_ext.pyi.ref
+++ b/tests/test_functions_ext.pyi.ref
@@ -5,6 +5,8 @@ from typing import Annotated, Any, overload
 
 def call_guard_value() -> int: ...
 
+def hash_it(arg: object, /) -> int: ...
+
 def identity_i16(arg: int, /) -> int: ...
 
 def identity_i32(arg: int, /) -> int: ...