Internal change

PiperOrigin-RevId: 352628261

pybind11_abseil/status_casters.h

@@ -106,8 +106,8 @@ struct type_caster<absl::Status> : public type_caster_base<absl::Status> {
 
  private:
   template <typename CType>
-  static handle cast_impl(CType src, return_value_policy policy, handle parent,
-                          bool throw_exception) {
+  static handle cast_impl(CType&& src, return_value_policy policy,
+                          handle parent, bool throw_exception) {
     google::CheckStatusModuleImported();
     if (!throw_exception) {
       // Use the built-in/standard pybind11 caster.

pybind11_abseil/status_utils.h

@@ -16,7 +16,8 @@ namespace pybind11 {
 namespace google {
 
 // Wrapper type to signal to the type_caster that a non-ok status should not
-// be converted into an object rather than a thrown exception.
+// be converted into an object rather than a thrown exception. StatusType can
+// encapsulate references, e.g. `NoThrowStatus<absl::Status&>`.
 template <typename StatusType>
 struct NoThrowStatus {
   NoThrowStatus(StatusType status_in)
@@ -24,7 +25,11 @@ struct NoThrowStatus {
   StatusType status;
 };
 
-// Convert a absl::Status(Or) into a NoThrowStatus.
+// Convert a absl::Status(Or) into a NoThrowStatus. To use this with references,
+// explicitly specify the template parameter rather deducing it, e.g.:
+// `return DoNotThrowStatus<const absl::Status&>(my_status);`
+// When returning a status by value (by far the most common case), deducing the
+// template parameter is fine, e.g.: `return DoNotThrowStatus(my_status);`
 template <typename StatusType>
 NoThrowStatus<StatusType> DoNotThrowStatus(StatusType status) {
   return NoThrowStatus<StatusType>(std::forward<StatusType>(status));
@@ -34,7 +39,7 @@ NoThrowStatus<StatusType> DoNotThrowStatus(StatusType status) {
 template <typename StatusType, typename... Args>
 std::function<NoThrowStatus<StatusType>(Args...)> DoNotThrowStatus(
     std::function<StatusType(Args...)> f) {
-  return [f = std::move(f)](Args... args) {
+  return [f = std::move(f)](Args&&... args) {
     return NoThrowStatus<StatusType>(
         std::forward<StatusType>(f(std::forward<Args>(args)...)));
   };
@@ -42,7 +47,7 @@ std::function<NoThrowStatus<StatusType>(Args...)> DoNotThrowStatus(
 template <typename StatusType, typename... Args>
 std::function<NoThrowStatus<StatusType>(Args...)> DoNotThrowStatus(
     StatusType (*f)(Args...)) {
-  return [f](Args... args) {
+  return [f](Args&&... args) {
     return NoThrowStatus<StatusType>(
         std::forward<StatusType>(f(std::forward<Args>(args)...)));
   };
@@ -50,7 +55,7 @@ std::function<NoThrowStatus<StatusType>(Args...)> DoNotThrowStatus(
 template <typename StatusType, typename Class, typename... Args>
 std::function<NoThrowStatus<StatusType>(Class*, Args...)> DoNotThrowStatus(
     StatusType (Class::*f)(Args...)) {
-  return [f](Class* c, Args... args) {
+  return [f](Class* c, Args&&... args) {
     return NoThrowStatus<StatusType>(
         std::forward<StatusType>((c->*f)(std::forward<Args>(args)...)));
   };
@@ -58,7 +63,7 @@ std::function<NoThrowStatus<StatusType>(Class*, Args...)> DoNotThrowStatus(
 template <typename StatusType, typename Class, typename... Args>
 std::function<NoThrowStatus<StatusType>(const Class*, Args...)>
 DoNotThrowStatus(StatusType (Class::*f)(Args...) const) {
-  return [f](const Class* c, Args... args) {
+  return [f](const Class* c, Args&&... args) {
     return NoThrowStatus<StatusType>(
         std::forward<StatusType>((c->*f)(std::forward<Args>(args)...)));
   };