ADIOS2 IO Handler: Fix data structure initialization order upon createFile/openFile (#1847)

* Only emplace files into structures after successfully opening

* Same for openFile

Author: franzpoeschel

src/IO/ADIOS/ADIOS2IOHandler.cpp

@@ -708,15 +708,19 @@ void ADIOS2IOHandlerImpl::createFile(
             VERIFY(success, "[ADIOS2] Could not create directory.");
         }
 
+        // enforce opening the file
+        // lazy opening is deathly in parallel situations
+        auto &fileData =
+            getFileData(shared_name, IfFileNotOpen::CreateImplicitly);
+
+        // only emplace the file into our structures after it has been
+        // successfully opened. otherwise, errors will lead to undefined state.
+
         associateWithFile(writable, shared_name);
         this->m_dirty.emplace(shared_name);
 
         writable->written = true;
         writable->abstractFilePosition = std::make_shared<ADIOS2FilePosition>();
-        // enforce opening the file
-        // lazy opening is deathly in parallel situations
-        auto &fileData =
-            getFileData(shared_name, IfFileNotOpen::CreateImplicitly);
 
         if (!printedWarningsAlready.noGroupBased &&
             m_writeAttributesFromThisRank &&
@@ -1028,14 +1032,8 @@ void ADIOS2IOHandlerImpl::openFile(
     }
 
     std::string name = parameters.name + fileSuffix();
-
     auto file = std::get<PE_InvalidatableFile>(getPossiblyExisting(name));
 
-    associateWithFile(writable, file);
-
-    writable->written = true;
-    writable->abstractFilePosition = std::make_shared<ADIOS2FilePosition>();
-
     auto how_to_open = [&]() {
         switch (parameters.reopen)
         {
@@ -1050,8 +1048,18 @@ void ADIOS2IOHandlerImpl::openFile(
     }();
 
     // enforce opening the file
-    // lazy opening is deathly in parallel situations
+    // lazy opening is deadly in parallel situations
     auto &fileData = getFileData(file, how_to_open);
+
+    // the following calls present the new file to the IO handler's data
+    // structures. do this only after the file has been successfully open, to
+    // avoid invalid state.
+
+    associateWithFile(writable, file);
+
+    writable->written = true;
+    writable->abstractFilePosition = std::make_shared<ADIOS2FilePosition>();
+
     *parameters.out_parsePreference = fileData.parsePreference;
     m_dirty.emplace(std::move(file));
 }