Cope with base function restrictions in mocks.

rcl/test/mocking_utils/patch.hpp

@@ -473,10 +473,22 @@ auto make_patch(const std::string & target, std::function<SignatureT> proxy)
 
 /// Patch a `function` to execute normally but always yield a given `return_code`
 /// in a given `scope`.
+/**
+ * \warning On some Linux distributions (e.g. CentOS), pointers to function
+ *   reference their PLT trampolines. In such cases, it is not possible to
+ *   call `function` from within the mock.
+ */
 #define inject_on_return(scope, function, return_code) \
   patch( \
     scope, function, ([&, base = function](auto && ... __args) { \
-      static_cast<void>(base(std::forward<decltype(__args)>(__args)...)); \
+      if (base != function) { \
+        static_cast<void>(base(std::forward<decltype(__args)>(__args)...)); \
+      } else { \
+        RCUTILS_SAFE_FWRITE_TO_STDERR( \
+          "[WARNING] mocking_utils::inject_on_return() cannot forward call to " \
+          "original '" RCUTILS_STRINGIFY(function) "' function before injection\n" \
+          "    at " __FILE__ ":" RCUTILS_STRINGIFY(__LINE__) "\n"); \
+      } \
       return return_code; \
     }))
 

rcl/test/rcl/test_logging.cpp

@@ -242,14 +242,13 @@ TEST(TestLogging, test_failing_external_logging) {
   std::stringstream stderr_sstream;
   auto fwrite_mock = mocking_utils::patch(
     "lib:rcl", fwrite,
-    ([&, base = fwrite](const void * ptr, size_t size,
-    size_t count, FILE * stream)
+    [&](const void * ptr, size_t size, size_t count, FILE * stream)
     {
       if (sizeof(char) == size && stderr == stream) {
         stderr_sstream << std::string(reinterpret_cast<const char *>(ptr), count);
       }
-      return base(ptr, size, count, stream);
-    }));
+      return count;
+    });
 
   constexpr char stderr_message[] = "internal error";
 #ifdef MOCKING_UTILS_SUPPORT_VA_LIST

rcl/test/rcl/test_rmw_impl_id_check_func.cpp

@@ -128,12 +128,15 @@ TEST(TestRmwCheck, test_mock_rmw_impl_check) {
 
     auto mock = mocking_utils::patch(
       "lib:rcl", rcutils_strdup,
-      [base = rcutils_strdup](const char * str, auto allocator)
+      [](const char * str, auto allocator)
       {
         static int counter = 1;
         if (counter == 1) {
           counter++;
-          return base(str, allocator);
+          char * dup = static_cast<char *>(
+            allocator.allocate(strlen(str) + 1, allocator.state));
+          memcpy(dup, str, strlen(str) + 1);
+          return dup;
         } else {
           return static_cast<char *>(NULL);
         }