Update for OPENPMD_VERBOSE logging (#1574)

* Log intercepted I/O exceptions in verbose mode

* Fix undefined behavior in verbose logging of deregister task

include/openPMD/IO/IOTask.hpp

@@ -30,6 +30,7 @@
 #include "openPMD/backend/Attribute.hpp"
 #include "openPMD/backend/ParsePreference.hpp"
 
+#include <cstddef>
 #include <map>
 #include <memory>
 #include <string>
@@ -680,15 +681,23 @@ template <>
 struct OPENPMDAPI_EXPORT Parameter<Operation::DEREGISTER>
     : public AbstractParameter
 {
-    Parameter() = default;
-    Parameter(Parameter const &) : AbstractParameter()
+    Parameter(void const *ptr_in) : former_parent(ptr_in)
     {}
 
+    Parameter(Parameter const &) = default;
+    Parameter(Parameter &&) = default;
+
+    Parameter &operator=(Parameter const &) = default;
+    Parameter &operator=(Parameter &&) = default;
+
     std::unique_ptr<AbstractParameter> to_heap() && override
     {
         return std::make_unique<Parameter<Operation::DEREGISTER>>(
             std::move(*this));
     }
+
+    // Just for verbose logging.
+    void const *former_parent = nullptr;
 };
 
 /** @brief Self-contained description of a single IO operation.

src/IO/AbstractIOHandlerImpl.cpp

@@ -358,24 +358,56 @@ std::future<void> AbstractIOHandlerImpl::flush()
                 auto &parameter = deref_dynamic_cast<Parameter<O::DEREGISTER>>(
                     i.parameter.get());
                 writeToStderr(
-                    "[", i.writable->parent, "->", i.writable, "] DEREGISTER");
+                    "[",
+                    parameter.former_parent,
+                    "->",
+                    i.writable,
+                    "] DEREGISTER");
                 deregister(i.writable, parameter);
                 break;
             }
             }
         }
         catch (...)
         {
-            std::cerr << "[AbstractIOHandlerImpl] IO Task "
-                      << internal::operationAsString(i.operation)
-                      << " failed with exception. Clearing IO queue and "
-                         "passing on the exception."
-                      << std::endl;
-            while (!m_handler->m_work.empty())
+            auto base_handler = [&i, this]() {
+                std::cerr << "[AbstractIOHandlerImpl] IO Task "
+                          << internal::operationAsString(i.operation)
+                          << " failed with exception. Clearing IO queue and "
+                             "passing on the exception."
+                          << std::endl;
+                while (!m_handler->m_work.empty())
+                {
+                    m_handler->m_work.pop();
+                }
+            };
+
+            if (m_verboseIOTasks)
+            {
+                try
+                {
+                    // Throw again so we can distinguish between std::exception
+                    // and other exception types.
+                    throw;
+                }
+                catch (std::exception const &e)
+                {
+                    base_handler();
+                    std::cerr << "Original exception: " << e.what()
+                              << std::endl;
+                    throw;
+                }
+                catch (...)
+                {
+                    base_handler();
+                    throw;
+                }
+            }
+            else
             {
-                m_handler->m_work.pop();
+                base_handler();
+                throw;
             }
-            throw;
         }
         (*m_handler).m_work.pop();
     }

src/backend/Writable.cpp

@@ -39,7 +39,7 @@ Writable::~Writable()
      * remove references to this object from internal data structures.
      */
     IOHandler->value()->enqueue(
-        IOTask(this, Parameter<Operation::DEREGISTER>()));
+        IOTask(this, Parameter<Operation::DEREGISTER>(parent)));
 }
 
 void Writable::seriesFlush(std::string backendConfig)