fix: Use default rcl allocator if allocator is std::allocator

rclcpp/include/rclcpp/allocator/allocator_common.hpp

@@ -27,10 +27,39 @@ namespace rclcpp
 namespace allocator
 {
 
+template<typename T>
+using clean_t = std::remove_cv_t<std::remove_reference_t<T>>;
+
+// Primary template: false
+template<typename, typename = std::void_t<>>
+struct has_get_rcl_allocator : std::false_type {};
+
+// Specialization: true if expression is valid
+template<typename T>
+struct has_get_rcl_allocator<T,
+  std::void_t<
+    decltype(std::declval<clean_t<T> &>().get_rcl_allocator())
+  >
+>
+  : std::bool_constant<
+    std::is_same_v<
+      decltype(std::declval<clean_t<T> &>().get_rcl_allocator()),
+      rcl_allocator_t
+    >
+  >
+{};
+
+// Helper variable template
+template<typename T>
+inline constexpr bool has_get_rcl_allocator_v =
+  has_get_rcl_allocator<T>::value;
+
 template<typename T, typename Alloc>
 using AllocRebind = typename std::allocator_traits<Alloc>::template rebind_traits<T>;
 
 template<typename Alloc>
+[[deprecated("Conversion of C++ allocators to C style is not valid, as the size on deallocate"
+  "can not be determined. This will be remove in future versions of ros.")]]
 void * retyped_allocate(size_t size, void * untyped_allocator)
 {
   auto typed_allocator = static_cast<Alloc *>(untyped_allocator);
@@ -41,6 +70,8 @@ void * retyped_allocate(size_t size, void * untyped_allocator)
 }
 
 template<typename Alloc>
+[[deprecated("Conversion of C++ allocators to C style is not valid, as the size on deallocate"
+  "can not be determined. This will be remove in future versions of ros.")]]
 void * retyped_zero_allocate(size_t number_of_elem, size_t size_of_elem, void * untyped_allocator)
 {
   auto typed_allocator = static_cast<Alloc *>(untyped_allocator);
@@ -57,6 +88,8 @@ void * retyped_zero_allocate(size_t number_of_elem, size_t size_of_elem, void *
 }
 
 template<typename T, typename Alloc>
+[[deprecated("Conversion of C++ allocators to C style is not valid, as the size on deallocate"
+  "can not be determined. This will be remove in future versions of ros.")]]
 void retyped_deallocate(void * untyped_pointer, void * untyped_allocator)
 {
   auto typed_allocator = static_cast<Alloc *>(untyped_allocator);
@@ -68,6 +101,8 @@ void retyped_deallocate(void * untyped_pointer, void * untyped_allocator)
 }
 
 template<typename T, typename Alloc>
+[[deprecated("Conversion of C++ allocators to C style is not valid, as the size on deallocate"
+  "can not be determined. This will be remove in future versions of ros.")]]
 void * retyped_reallocate(void * untyped_pointer, size_t size, void * untyped_allocator)
 {
   auto typed_allocator = static_cast<Alloc *>(untyped_allocator);
@@ -85,6 +120,9 @@ template<
   typename T,
   typename Alloc,
   typename std::enable_if<!std::is_same<Alloc, std::allocator<void>>::value>::type * = nullptr>
+[[deprecated("Conversion of C++ allocators to C style is not valid, as the size on deallocate"
+  "can not be determined. This will be remove in future versions of ros. To suppress this warning"
+  "define the method 'rcl_allocator_t get_rcl_allocator()' on your allocator")]]
 rcl_allocator_t get_rcl_allocator(Alloc & allocator)
 {
   rcl_allocator_t rcl_allocator = rcl_get_default_allocator();

rclcpp/include/rclcpp/message_memory_strategy.hpp

@@ -18,6 +18,7 @@
 #include <memory>
 #include <stdexcept>
 
+#include "rcl/allocator.h"
 #include "rcl/types.h"
 
 #include "rclcpp/allocator/allocator_common.hpp"
@@ -61,15 +62,33 @@ class MessageMemoryStrategy
     message_allocator_ = std::make_shared<MessageAlloc>();
     serialized_message_allocator_ = std::make_shared<SerializedMessageAlloc>();
     buffer_allocator_ = std::make_shared<BufferAlloc>();
-    rcutils_allocator_ = allocator::get_rcl_allocator<char, BufferAlloc>(*buffer_allocator_.get());
+    if constexpr (std::is_same_v<Alloc, std::allocator<void>>) {
+      rcutils_allocator_ = rcl_get_default_allocator();
+    } else {
+      if constexpr (rclcpp::allocator::has_get_rcl_allocator_v<Alloc>) {
+        rcutils_allocator_ = message_allocator_->get_rcl_allocator();
+      } else {
+        rcutils_allocator_ = allocator::get_rcl_allocator<char,
+            BufferAlloc>(*buffer_allocator_.get());
+      }
+    }
   }
 
   explicit MessageMemoryStrategy(std::shared_ptr<Alloc> allocator)
   {
     message_allocator_ = std::make_shared<MessageAlloc>(*allocator.get());
     serialized_message_allocator_ = std::make_shared<SerializedMessageAlloc>(*allocator.get());
     buffer_allocator_ = std::make_shared<BufferAlloc>(*allocator.get());
-    rcutils_allocator_ = allocator::get_rcl_allocator<char, BufferAlloc>(*buffer_allocator_.get());
+    if constexpr (std::is_same_v<Alloc, std::allocator<void>>) {
+      rcutils_allocator_ = rcl_get_default_allocator();
+    } else {
+      if constexpr (rclcpp::allocator::has_get_rcl_allocator_v<Alloc>) {
+        rcutils_allocator_ = allocator->get_rcl_allocator();
+      } else {
+        rcutils_allocator_ = allocator::get_rcl_allocator<char,
+            BufferAlloc>(*buffer_allocator_.get());
+      }
+    }
   }
 
   virtual ~MessageMemoryStrategy() = default;

rclcpp/include/rclcpp/publisher_options.hpp

@@ -123,11 +123,20 @@ struct PublisherOptionsWithAllocator : public PublisherOptionsBase
   rcl_allocator_t
   get_rcl_allocator() const
   {
-    if (!plain_allocator_storage_) {
-      plain_allocator_storage_ =
-        std::make_shared<PlainAllocator>(*this->get_allocator());
+    if constexpr (std::is_same_v<Allocator, std::allocator<void>>) {
+      return rcl_get_default_allocator();
+    } else {
+      if constexpr (rclcpp::allocator::has_get_rcl_allocator_v<Allocator>) {
+        return get_allocator()->get_rcl_allocator();
+      } else {
+        if (!plain_allocator_storage_) {
+          plain_allocator_storage_ =
+            std::make_shared<PlainAllocator>(*this->get_allocator());
+        }
+
+        return rclcpp::allocator::get_rcl_allocator<char>(*plain_allocator_storage_);
+      }
     }
-    return rclcpp::allocator::get_rcl_allocator<char>(*plain_allocator_storage_);
   }
 
   // This is a temporal workaround, to make sure that get_allocator()

rclcpp/include/rclcpp/strategies/allocator_memory_strategy.hpp

@@ -515,7 +515,11 @@ class AllocatorMemoryStrategy : public memory_strategy::MemoryStrategy
 
   rcl_allocator_t get_allocator() override
   {
-    return rclcpp::allocator::get_rcl_allocator<void *, VoidAlloc>(*allocator_.get());
+    if constexpr (std::is_same_v<Alloc, std::allocator<void>>) {
+      return rcl_get_default_allocator();
+    } else {
+      return rclcpp::allocator::get_rcl_allocator<void *, VoidAlloc>(*allocator_.get());
+    }
   }
 
   size_t number_of_ready_subscriptions() const override

rclcpp/include/rclcpp/subscription_options.hpp

@@ -167,11 +167,20 @@ struct SubscriptionOptionsWithAllocator : public SubscriptionOptionsBase
   rcl_allocator_t
   get_rcl_allocator() const
   {
-    if (!plain_allocator_storage_) {
-      plain_allocator_storage_ =
-        std::make_shared<PlainAllocator>(*this->get_allocator());
+    if constexpr (std::is_same_v<Allocator, std::allocator<void>>) {
+      return rcl_get_default_allocator();
+    } else {
+      if constexpr (rclcpp::allocator::has_get_rcl_allocator_v<Allocator>) {
+        return get_allocator()->get_rcl_allocator();
+      } else {
+        if (!plain_allocator_storage_) {
+          plain_allocator_storage_ =
+            std::make_shared<PlainAllocator>(*this->get_allocator());
+        }
+
+        return rclcpp::allocator::get_rcl_allocator<char>(*plain_allocator_storage_);
+      }
     }
-    return rclcpp::allocator::get_rcl_allocator<char>(*plain_allocator_storage_);
   }
 
   // This is a temporal workaround, to make sure that get_allocator()

rclcpp/test/rclcpp/allocator/test_allocator_common.cpp

@@ -17,10 +17,12 @@
 #include <memory>
 
 #include "rclcpp/allocator/allocator_common.hpp"
+#include "rcpputils/compile_warnings.hpp"
 
 TEST(TestAllocatorCommon, retyped_allocate) {
   std::allocator<int> allocator;
   void * untyped_allocator = &allocator;
+RCPPUTILS_DEPRECATION_WARNING_OFF_START
   void * allocated_mem =
     rclcpp::allocator::retyped_allocate<std::allocator<char>>(1u, untyped_allocator);
   // The more natural check here is ASSERT_NE(nullptr, ptr), but clang static
@@ -49,9 +51,12 @@ TEST(TestAllocatorCommon, retyped_allocate) {
         reallocated_mem, untyped_allocator);
     };
   EXPECT_NO_THROW(code2());
+
+RCPPUTILS_DEPRECATION_WARNING_OFF_STOP
 }
 
 TEST(TestAllocatorCommon, retyped_zero_allocate_basic) {
+RCPPUTILS_DEPRECATION_WARNING_OFF_START
   std::allocator<int> allocator;
   void * untyped_allocator = &allocator;
   void * allocated_mem =
@@ -63,9 +68,11 @@ TEST(TestAllocatorCommon, retyped_zero_allocate_basic) {
         allocated_mem, untyped_allocator);
     };
   EXPECT_NO_THROW(code());
+RCPPUTILS_DEPRECATION_WARNING_OFF_STOP
 }
 
 TEST(TestAllocatorCommon, retyped_zero_allocate) {
+RCPPUTILS_DEPRECATION_WARNING_OFF_START
   std::allocator<int> allocator;
   void * untyped_allocator = &allocator;
   void * allocated_mem =
@@ -96,19 +103,24 @@ TEST(TestAllocatorCommon, retyped_zero_allocate) {
         reallocated_mem, untyped_allocator);
     };
   EXPECT_NO_THROW(code2());
+RCPPUTILS_DEPRECATION_WARNING_OFF_STOP
 }
 
 TEST(TestAllocatorCommon, get_rcl_allocator) {
+RCPPUTILS_DEPRECATION_WARNING_OFF_START
   std::allocator<int> allocator;
   auto rcl_allocator = rclcpp::allocator::get_rcl_allocator<int>(allocator);
   EXPECT_NE(nullptr, rcl_allocator.allocate);
   EXPECT_NE(nullptr, rcl_allocator.deallocate);
   EXPECT_NE(nullptr, rcl_allocator.reallocate);
   EXPECT_NE(nullptr, rcl_allocator.zero_allocate);
   // Not testing state as that may or may not be null depending on platform
+RCPPUTILS_DEPRECATION_WARNING_OFF_STOP
 }
 
 TEST(TestAllocatorCommon, get_void_rcl_allocator) {
+RCPPUTILS_DEPRECATION_WARNING_OFF_START
+
   std::allocator<void> allocator;
   auto rcl_allocator =
     rclcpp::allocator::get_rcl_allocator<void, std::allocator<void>>(allocator);
@@ -117,4 +129,5 @@ TEST(TestAllocatorCommon, get_void_rcl_allocator) {
   EXPECT_NE(nullptr, rcl_allocator.reallocate);
   EXPECT_NE(nullptr, rcl_allocator.zero_allocate);
   // Not testing state as that may or may not be null depending on platform
+RCPPUTILS_DEPRECATION_WARNING_OFF_STOP
 }

rclcpp/test/rclcpp/test_intra_process_manager_with_allocators.cpp

@@ -75,6 +75,11 @@ struct MyAllocator
   {
     typedef MyAllocator<U> other;
   };
+
+  rcl_allocator_t get_rcl_allocator()
+  {
+    return rcl_get_default_allocator();
+  }
 };
 
 // Explicit specialization for void
@@ -102,6 +107,11 @@ struct MyAllocator<void>
   {
     typedef MyAllocator<U> other;
   };
+
+  rcl_allocator_t get_rcl_allocator()
+  {
+    return rcl_get_default_allocator();
+  }
 };
 
 template<typename T, typename U>