move to local internals

include/pybind11/detail/internals.h

@@ -28,7 +28,7 @@
 /// further ABI-incompatible changes may be made before the ABI is officially
 /// changed to the new version.
 #ifndef PYBIND11_INTERNALS_VERSION
-#    define PYBIND11_INTERNALS_VERSION 4
+#    define PYBIND11_INTERNALS_VERSION 5
 #endif
 
 PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
@@ -477,7 +477,7 @@ PYBIND11_NOINLINE internals &get_internals() {
 struct local_internals {
     type_map<type_info *> registered_types_cpp;
     std::forward_list<ExceptionTranslator> registered_exception_translators;
-#if defined(WITH_THREAD) && PYBIND11_INTERNALS_VERSION == 4
+#if defined(WITH_THREAD) && PYBIND11_INTERNALS_VERSION >= 4
 
     // For ABI compatibility, we can't store the loader_life_support TLS key in
     // the `internals` struct directly.  Instead, we store it in `shared_data` and
@@ -509,7 +509,10 @@ struct local_internals {
         loader_life_support_tls_key
             = static_cast<shared_loader_life_support_data *>(ptr)->loader_life_support_tls_key;
     }
-#endif //  defined(WITH_THREAD) && PYBIND11_INTERNALS_VERSION == 4
+#endif //  defined(WITH_THREAD) && PYBIND11_INTERNALS_VERSION >= 4
+#if PYBIND11_INTERNALS_VERSION == 5
+    const char* function_capsule_name = strdup("pybind11_function_capsule");
+#endif
 };
 
 /// Works like `get_internals`, but for things which are locally registered.
@@ -523,6 +526,14 @@ inline local_internals &get_local_internals() {
     return *locals;
 }
 
+inline const char* get_function_capsule_name() {
+#if PYBIND11_INTERNALS_VERSION == 5
+    return get_local_internals().function_capsule_name;
+#else
+    return nullptr;
+#endif
+}
+
 /// Constructs a std::string with the given arguments, stores it in `internals`, and returns its
 /// `c_str()`.  Such strings objects have a long storage duration -- the internal strings are only
 /// cleared when the program exits or after interpreter shutdown (when embedding), and so are

include/pybind11/pybind11.h

@@ -69,15 +69,9 @@ inline bool apply_exception_translators(std::forward_list<ExceptionTranslator> &
     return false;
 }
 
-// Need to use a wrapper function to ensure 1 address
-inline const char *function_capsule_name() {
-    static char name[] = "pybind11_function_capsule";
-    return name;
-}
-
 inline bool is_function_record_capsule(const capsule &cap) {
     // Compare the pointers, not the values to ensure that each extension is unique
-    return cap.name() == function_capsule_name();
+    return cap.name() == get_function_capsule_name();
 }
 
 #if defined(_MSC_VER)
@@ -514,7 +508,7 @@ class cpp_function : public function {
 
             capsule rec_capsule(unique_rec.release(),
                                 [](void *ptr) { destruct((detail::function_record *) ptr); });
-            rec_capsule.set_name(detail::function_capsule_name());
+            rec_capsule.set_name(detail::get_function_capsule_name());
             guarded_strdup.release();
 
             object scope_module;
@@ -683,7 +677,7 @@ class cpp_function : public function {
 
         /* Iterator over the list of potentially admissible overloads */
         const function_record *overloads = reinterpret_cast<function_record *>(
-                                  PyCapsule_GetPointer(self, function_capsule_name())),
+                                  PyCapsule_GetPointer(self, get_function_capsule_name())),
                               *it = overloads;
         assert(overloads != nullptr);