Added gil_scoped_release support to functions using a regex as acl

src/litgen/internal/adapted_types/adapted_function.py

@@ -549,6 +549,19 @@ def _pydef_end_arg_docstring_returnpolicy(self) -> str:
         replace_lines.maybe_keep_alive = self._pydef_fill_keep_alive_from_function_comment()
         replace_lines.maybe_call_guard = self._pydef_fill_call_guard_from_function_comment()
 
+        # Add gil_scoped_release call guard if regex matches
+        if code_utils.does_match_regex_or_matcher(
+            self.options.fn_add_gil_scoped_release_guard__regex, self.cpp_element().function_name
+        ):
+            py_ns = "py" if self.options.bind_library == BindLibraryType.pybind11 else "nb"
+            gil_guard = f"{py_ns}::call_guard<{py_ns}::gil_scoped_release>()"
+            if replace_lines.maybe_call_guard is None:
+                replace_lines.maybe_call_guard = gil_guard
+            else:
+                # If a call guard is already present from comments, append the new one.
+                # Note: pybind11 supports multiple call guards.
+                replace_lines.maybe_call_guard += f", {gil_guard}"
+
         # Process template
         code = code_utils.process_code_template(
             input_string=template_code,

src/litgen/options.py

@@ -243,6 +243,13 @@ class LitgenOptions:
     #     error: no matching function for call to object of type 'const detail::overload_cast_impl<...>'
     fn_force_lambda__regex: RegexOrMatcher = ""
 
+    # ------------------------------------------------------------------------------
+    # Add py::call_guard<py::gil_scoped_release>()
+    # ------------------------------------------------------------------------------
+    # Add a GIL release call guard for functions that matches these regexes.
+    # This is useful for long-running C++ functions that don't need to interact with Python objects.
+    fn_add_gil_scoped_release_guard__regex: RegexOrMatcher = ""
+
     # ------------------------------------------------------------------------------
     # C style buffers to py::array
     # ------------------------------------------------------------------------------

src/litgen/tests/internal/adapted_types/adapted_function_test.py

@@ -127,6 +127,38 @@ def test_return_policy_regex() -> None:
         """,
     )
 
+def test_gil_scoped_release_py() -> None:
+    options = LitgenOptions()
+    options.bind_library = litgen.BindLibraryType.pybind11
+    options.fn_add_gil_scoped_release_guard__regex = r"^Foo"
+
+    code = """
+    void Foo();
+    """
+    generated_code = LitgenGeneratorTestsHelper.code_to_pydef(options, code)
+    expected_code = """
+        m.def("foo",
+            Foo, py::call_guard<py::gil_scoped_release>());
+        """
+    # logging.warning("\n" + generated_code)
+    code_utils.assert_are_codes_equal(generated_code, expected_code)
+
+def test_gil_scoped_release_nb() -> None:
+    options = LitgenOptions()
+    options.bind_library = litgen.BindLibraryType.nanobind
+    options.fn_add_gil_scoped_release_guard__regex = r"^Foo"
+
+    code = """
+    void Foo();
+    """
+    generated_code = LitgenGeneratorTestsHelper.code_to_pydef(options, code)
+    expected_code = """
+        m.def("foo",
+            Foo, nb::call_guard<nb::gil_scoped_release>());
+        """
+    code_utils.assert_are_codes_equal(generated_code, expected_code)
+
+
 
 def test_implot_one_buffer() -> None:
     options = LitgenOptions()