Use PyModExport and PyABIInfo APIs in pymodule implementation

newsfragments/5753.changed.md

@@ -0,0 +1 @@
+Module initialization uses the PyModExport and PyABIInfo APIs on python 3.15 and newer.

pyo3-macros-backend/src/module.rs

@@ -511,6 +511,7 @@ fn module_initialization(
 ) -> TokenStream {
     let Ctx { pyo3_path, .. } = ctx;
     let pyinit_symbol = format!("PyInit_{name}");
+    let pymodexport_symbol = format!("PyModExport_{name}");
     let pyo3_name = LitCStr::new(&CString::new(full_name).unwrap(), Span::call_site());
 
     let mut result = quote! {
@@ -531,23 +532,47 @@ fn module_initialization(
                 #pyo3_path::impl_::trampoline::module_exec(module, #module_exec)
             }
 
-            static SLOTS: impl_::PyModuleSlots<4> = impl_::PyModuleSlotsBuilder::new()
+            // The full slots, used for the PyModExport initializaiton
+            static SLOTS: impl_::PyModuleSlots = impl_::PyModuleSlotsBuilder::new()
                 .with_mod_exec(__pyo3_module_exec)
+                .with_abi_info()
                 .with_gil_used(#gil_used)
+                .with_name(__PYO3_NAME)
+                .with_doc(#doc)
                 .build();
 
-            impl_::ModuleDef::new(__PYO3_NAME, #doc, &SLOTS)
+            // Used for old-style PyModuleDef initialization
+            // CPython doesn't allow specifying slots like the name and docstring that
+            // can be defined in PyModuleDef, so we skip those slots
+            static SLOTS_MINIMAL: impl_::PyModuleSlots = impl_::PyModuleSlotsBuilder::new()
+                .with_mod_exec(__pyo3_module_exec)
+                .with_abi_info()
+                .with_gil_used(#gil_used)
+                .build();
+
+            // Since the macros need to be written agnostic to the Python version
+            // we need to explicitly pass the name and docstring for PyModuleDef
+            // initializaiton.
+            impl_::ModuleDef::new(__PYO3_NAME, #doc, &SLOTS, &SLOTS_MINIMAL)
         };
     };
     if !is_submodule {
         result.extend(quote! {
             /// This autogenerated function is called by the python interpreter when importing
-            /// the module.
+            /// the module on Python 3.14 and older.
             #[doc(hidden)]
             #[export_name = #pyinit_symbol]
             pub unsafe extern "C" fn __pyo3_init() -> *mut #pyo3_path::ffi::PyObject {
                 _PYO3_DEF.init_multi_phase()
             }
+
+            /// This autogenerated function is called by the python interpreter when importing
+            /// the module on Python 3.15 and newer.
+            #[doc(hidden)]
+            #[export_name = #pymodexport_symbol]
+            pub unsafe extern "C" fn __pyo3_export() -> *mut #pyo3_path::ffi::PyModuleDef_Slot {
+                _PYO3_DEF.get_slots()
+            }
         });
     }
     result