Add `.as_absl_Status()` raw pointer capsule feature to `type_caster<absl::Status>::load()`

For interoperability with other Python binding systems (e.g. SWIG).

PiperOrigin-RevId: 487000705

pybind11_abseil/BUILD

@@ -50,6 +50,7 @@ pybind_library(
     deps = [
     deps = [
         ":check_status_module_imported",
         ":check_status_module_imported",
         ":no_throw_status",
         ":no_throw_status",
+        ":raw_ptr_from_capsule",
         ":status_not_ok_exception",
         ":status_not_ok_exception",
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/status:statusor",

pybind11_abseil/status_caster.h

@@ -11,6 +11,7 @@
 #include "absl/status/status.h"
 #include "absl/status/status.h"
 #include "pybind11_abseil/check_status_module_imported.h"
 #include "pybind11_abseil/check_status_module_imported.h"
 #include "pybind11_abseil/no_throw_status.h"
 #include "pybind11_abseil/no_throw_status.h"
+#include "pybind11_abseil/raw_ptr_from_capsule.h"
 #include "pybind11_abseil/status_not_ok_exception.h"
 #include "pybind11_abseil/status_not_ok_exception.h"
 
 
 namespace pybind11 {
 namespace pybind11 {
@@ -68,6 +69,22 @@ struct type_caster<absl::Status> : public type_caster_base<absl::Status> {
     return cast_impl(std::move(src), policy, parent, throw_exception);
     return cast_impl(std::move(src), policy, parent, throw_exception);
   }
   }
 
 
+  bool load(handle src, bool convert) {
+    if (type_caster_base<absl::Status>::load(src, convert)) {
+      return true;
+    }
+    if (convert) {
+      absl::StatusOr<void*> raw_ptr =
+          pybind11_abseil::raw_ptr_from_capsule::RawPtrFromCapsule<void>(
+              src.ptr(), "::absl::Status", "as_absl_Status");
+      if (raw_ptr.ok()) {
+        value = raw_ptr.value();
+        return true;
+      }
+    }
+    return false;
+  }
+
  private:
  private:
   template <typename CType>
   template <typename CType>
   static handle cast_impl(CType&& src, return_value_policy policy,
   static handle cast_impl(CType&& src, return_value_policy policy,

pybind11_abseil/tests/status_example.cc

@@ -105,6 +105,20 @@ PYBIND11_MODULE(status_example, m) {
   auto status_module = pybind11::google::ImportStatusModule();
   auto status_module = pybind11::google::ImportStatusModule();
   m.attr("StatusNotOk") = status_module.attr("StatusNotOk");
   m.attr("StatusNotOk") = status_module.attr("StatusNotOk");
 
 
+  m.def("make_absl_status_capsule", [](bool return_ok_status) {
+    static absl::Status ok_status;
+    static absl::Status not_ok_status(absl::StatusCode::kAlreadyExists,
+                                      "Made by make_absl_status_capsule.");
+    if (return_ok_status) {
+      return capsule(static_cast<void*>(&ok_status), "::absl::Status");
+    }
+    return capsule(static_cast<void*>(&not_ok_status), "::absl::Status");
+  });
+
+  m.def("extract_code_message", [](const absl::Status& status) {
+    return pybind11::make_tuple(status.code(), std::string(status.message()));
+  });
+
   m.def("make_bad_capsule", [](bool pass_name) {
   m.def("make_bad_capsule", [](bool pass_name) {
     // https://docs.python.org/3/c-api/capsule.html:
     // https://docs.python.org/3/c-api/capsule.html:
     // The pointer argument may not be NULL.
     // The pointer argument may not be NULL.

pybind11_abseil/tests/status_test.py

@@ -13,6 +13,15 @@ def docstring_signature(f):
   return f.__doc__.split('\n')[0]
   return f.__doc__.split('\n')[0]
 
 
 
 
+class AbslStatusCapsule:
+
+  def __init__(self, return_ok_status):
+    self.return_ok_status = return_ok_status
+
+  def as_absl_Status(self):  # pylint: disable=invalid-name
+    return status_example.make_absl_status_capsule(self.return_ok_status)
+
+
 class BadCapsule:
 class BadCapsule:
 
 
   def __init__(self, pass_name):
   def __init__(self, pass_name):
@@ -378,6 +387,34 @@ class StatusTest(parameterized.TestCase):
         f'NotACapsule.as_absl_Status() returned an object ({nm})'
         f'NotACapsule.as_absl_Status() returned an object ({nm})'
         f' that is not a capsule.')
         f' that is not a capsule.')
 
 
+  @parameterized.parameters(False, True)
+  def test_status_caster_load_as_absl_status_success(self, return_ok_status):
+    code, msg = status_example.extract_code_message(
+        AbslStatusCapsule(return_ok_status))
+    if return_ok_status:
+      self.assertEqual(code, status.StatusCode.OK)
+      self.assertEqual(msg, '')
+    else:
+      self.assertEqual(code, status.StatusCode.ALREADY_EXISTS)
+      self.assertEqual(msg, 'Made by make_absl_status_capsule.')
+
+  @parameterized.parameters(False, True)
+  def test_status_caster_load_as_absl_status_bad_capsule(self, pass_name):
+    cap = BadCapsule(pass_name)
+    with self.assertRaises(TypeError):
+      status_example.extract_code_message(cap)
+
+  @parameterized.parameters(None, '', 0)
+  def test_status_caster_load_as_absl_status_not_a_capsule(self, not_a_capsule):
+    cap = NotACapsule(not_a_capsule)
+    with self.assertRaises(TypeError):
+      status_example.extract_code_message(cap)
+
+  @parameterized.parameters(None, '', 0)
+  def test_status_caster_load_no_as_absl_status(self, something_random):
+    with self.assertRaises(TypeError):
+      status_example.extract_code_message(something_random)
+
 
 
 class IntGetter(status_example.IntGetter):
 class IntGetter(status_example.IntGetter):