Factor out pybind11/gil_simple.h (#5614)

* Factor out pybind11/gil_simple.h

* Remove disarm() member functions in pybind11/gil_simple.h

Author: rwgk

CMakeLists.txt

@@ -158,6 +158,7 @@ set(PYBIND11_HEADERS
     include/pybind11/eval.h
     include/pybind11/gil.h
     include/pybind11/gil_safe_call_once.h
+    include/pybind11/gil_simple.h
     include/pybind11/iostream.h
     include/pybind11/functional.h
     include/pybind11/native_enum.h

include/pybind11/detail/internals.h

@@ -9,15 +9,12 @@
 
 #pragma once
 
-#include "common.h"
-
-#if defined(PYBIND11_SIMPLE_GIL_MANAGEMENT)
-#    include <pybind11/gil.h>
-#endif
-
 #include <pybind11/conduit/pybind11_platform_abi_id.h>
+#include <pybind11/gil_simple.h>
 #include <pybind11/pytypes.h>
 
+#include "common.h"
+
 #include <exception>
 #include <mutex>
 #include <thread>
@@ -425,19 +422,7 @@ PYBIND11_NOINLINE internals &get_internals() {
         return **internals_pp;
     }
 
-#if defined(PYBIND11_SIMPLE_GIL_MANAGEMENT)
-    gil_scoped_acquire gil;
-#else
-    // Ensure that the GIL is held since we will need to make Python calls.
-    // Cannot use py::gil_scoped_acquire here since that constructor calls get_internals.
-    struct gil_scoped_acquire_local {
-        gil_scoped_acquire_local() : state(PyGILState_Ensure()) {}
-        gil_scoped_acquire_local(const gil_scoped_acquire_local &) = delete;
-        gil_scoped_acquire_local &operator=(const gil_scoped_acquire_local &) = delete;
-        ~gil_scoped_acquire_local() { PyGILState_Release(state); }
-        const PyGILState_STATE state;
-    } gil;
-#endif
+    gil_scoped_acquire_simple gil;
     error_scope err_scope;
 
     dict state_dict = get_python_state_dict();

include/pybind11/gil.h

@@ -9,13 +9,24 @@
 
 #pragma once
 
-#include "detail/common.h"
+#if defined(PYBIND11_SIMPLE_GIL_MANAGEMENT)
 
-#include <cassert>
+#    include "detail/common.h"
+#    include "gil_simple.h"
 
-#if !defined(PYBIND11_SIMPLE_GIL_MANAGEMENT)
+PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+
+using gil_scoped_acquire = gil_scoped_acquire_simple;
+using gil_scoped_release = gil_scoped_release_simple;
+
+PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
+
+#else
+
+#    include "detail/common.h"
 #    include "detail/internals.h"
-#endif
+
+#    include <cassert>
 
 PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
@@ -26,8 +37,6 @@ PyThreadState *get_thread_state_unchecked();
 
 PYBIND11_NAMESPACE_END(detail)
 
-#if !defined(PYBIND11_SIMPLE_GIL_MANAGEMENT)
-
 /* The functions below essentially reproduce the PyGILState_* API using a RAII
  * pattern, but there are a few important differences:
  *
@@ -182,34 +191,6 @@ class gil_scoped_release {
     bool active = true;
 };
 
-#else // PYBIND11_SIMPLE_GIL_MANAGEMENT
-
-class gil_scoped_acquire {
-    PyGILState_STATE state;
-
-public:
-    gil_scoped_acquire() : state{PyGILState_Ensure()} {}
-    gil_scoped_acquire(const gil_scoped_acquire &) = delete;
-    gil_scoped_acquire &operator=(const gil_scoped_acquire &) = delete;
-    ~gil_scoped_acquire() { PyGILState_Release(state); }
-    void disarm() {}
-};
-
-class gil_scoped_release {
-    PyThreadState *state;
-
-public:
-    // PRECONDITION: The GIL must be held when this constructor is called.
-    gil_scoped_release() {
-        assert(PyGILState_Check());
-        state = PyEval_SaveThread();
-    }
-    gil_scoped_release(const gil_scoped_release &) = delete;
-    gil_scoped_release &operator=(const gil_scoped_release &) = delete;
-    ~gil_scoped_release() { PyEval_RestoreThread(state); }
-    void disarm() {}
-};
-
-#endif // PYBIND11_SIMPLE_GIL_MANAGEMENT
-
 PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
+
+#endif // !PYBIND11_SIMPLE_GIL_MANAGEMENT

include/pybind11/gil_simple.h

@@ -0,0 +1,37 @@
+// Copyright (c) 2016-2025 The Pybind Development Team.
+// All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#pragma once
+
+#include "detail/common.h"
+
+#include <cassert>
+
+PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+
+class gil_scoped_acquire_simple {
+    PyGILState_STATE state;
+
+public:
+    gil_scoped_acquire_simple() : state{PyGILState_Ensure()} {}
+    gil_scoped_acquire_simple(const gil_scoped_acquire_simple &) = delete;
+    gil_scoped_acquire_simple &operator=(const gil_scoped_acquire_simple &) = delete;
+    ~gil_scoped_acquire_simple() { PyGILState_Release(state); }
+};
+
+class gil_scoped_release_simple {
+    PyThreadState *state;
+
+public:
+    // PRECONDITION: The GIL must be held when this constructor is called.
+    gil_scoped_release_simple() {
+        assert(PyGILState_Check());
+        state = PyEval_SaveThread();
+    }
+    gil_scoped_release_simple(const gil_scoped_release_simple &) = delete;
+    gil_scoped_release_simple &operator=(const gil_scoped_release_simple &) = delete;
+    ~gil_scoped_release_simple() { PyEval_RestoreThread(state); }
+};
+
+PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)

tests/extra_python_package/test_files.py

@@ -37,6 +37,7 @@
     "include/pybind11/functional.h",
     "include/pybind11/gil.h",
     "include/pybind11/gil_safe_call_once.h",
+    "include/pybind11/gil_simple.h",
     "include/pybind11/iostream.h",
     "include/pybind11/native_enum.h",
     "include/pybind11/numpy.h",