[ntuple] add type version, checksum to type trace report

Author: jblomer

tree/ntuple/src/RFieldUtils.cxx

@@ -726,12 +726,26 @@ bool ROOT::Internal::IsMatchingFieldType(std::string_view actualTypeName, std::s
 
 std::string ROOT::Internal::GetTypeTraceReport(const RFieldBase &field, const RNTupleDescriptor &desc)
 {
+   // Information to print in a single line of the type trace
+   struct RFieldInfo {
+      std::string fFieldName;
+      std::string fTypeName;
+      DescriptorId_t fFieldId = kInvalidDescriptorId;
+      std::uint32_t fTypeVersion = 0;
+      std::optional<std::uint32_t> fTypeChecksum;
+   };
+
    std::vector<const RFieldBase *> inMemoryStack;
    std::vector<const RFieldDescriptor *> onDiskStack;
 
-   auto fnGetLine = [](const std::string &fieldName, const std::string &fieldType, DescriptorId_t fieldId,
-                       int level) -> std::string {
-      return std::string(2 * level, ' ') + fieldName + " [" + fieldType + "] (id: " + std::to_string(fieldId) + ")\n";
+   auto fnGetLine = [](const RFieldInfo &fieldInfo, int level) -> std::string {
+      std::string line = std::string(2 * level, ' ') + fieldInfo.fFieldName + " [" + fieldInfo.fTypeName;
+      if (fieldInfo.fTypeVersion > 0)
+         line += ", type version: " + std::to_string(fieldInfo.fTypeVersion);
+      if (fieldInfo.fTypeChecksum)
+         line += ", type checksum: " + std::to_string(*fieldInfo.fTypeChecksum);
+      line += "] (id: " + std::to_string(fieldInfo.fFieldId) + ")\n";
+      return line;
    };
 
    const RFieldBase *fieldPtr = &field;
@@ -750,13 +764,28 @@ std::string ROOT::Internal::GetTypeTraceReport(const RFieldBase &field, const RN
    std::string report = "In-memory field/type hierarchy:\n";
    int indentLevel = 0;
    for (auto itr = inMemoryStack.rbegin(); itr != inMemoryStack.rend(); ++itr, ++indentLevel) {
-      report += fnGetLine((*itr)->GetFieldName(), (*itr)->GetTypeName(), (*itr)->GetOnDiskId(), indentLevel);
+      RFieldInfo fieldInfo;
+      fieldInfo.fFieldName = (*itr)->GetFieldName();
+      fieldInfo.fTypeName = (*itr)->GetTypeName();
+      fieldInfo.fFieldId = (*itr)->GetOnDiskId();
+      fieldInfo.fTypeVersion = (*itr)->GetTypeVersion();
+      if ((*itr)->GetTraits() & RFieldBase::kTraitTypeChecksum)
+         fieldInfo.fTypeChecksum = (*itr)->GetTypeChecksum();
+
+      report += fnGetLine(fieldInfo, indentLevel);
    }
 
    report += "On-disk field/type hierarchy:\n";
    indentLevel = 0;
    for (auto itr = onDiskStack.rbegin(); itr != onDiskStack.rend(); ++itr, ++indentLevel) {
-      report += fnGetLine((*itr)->GetFieldName(), (*itr)->GetTypeName(), (*itr)->GetId(), indentLevel);
+      RFieldInfo fieldInfo;
+      fieldInfo.fFieldName = (*itr)->GetFieldName();
+      fieldInfo.fTypeName = (*itr)->GetTypeName();
+      fieldInfo.fFieldId = (*itr)->GetId();
+      fieldInfo.fTypeVersion = (*itr)->GetTypeVersion();
+      fieldInfo.fTypeChecksum = (*itr)->GetTypeChecksum();
+
+      report += fnGetLine(fieldInfo, indentLevel);
    }
 
    return report;

tree/ntuple/test/CustomStruct.hxx

@@ -214,6 +214,8 @@ struct StructUsingCollectionProxy {
 /// Classes to exercise field traits
 struct TrivialTraitsBase {
    int a;
+
+   ClassDefNV(TrivialTraitsBase, 5)
 };
 
 struct TrivialTraits : TrivialTraitsBase {

tree/ntuple/test/ntuple_show.cxx

@@ -648,34 +648,37 @@ TEST(RNTupleShow, TypeTraceReport)
    FileRaii fileGuard("test_ntuple_show_type_trace_report.ntuple");
    {
       auto model = RNTupleModel::Create();
-      model->MakeField<std::variant<double, std::vector<std::pair<float, bool>>>>("f");
+      model->MakeField<std::variant<double, std::vector<std::pair<float, TrivialTraitsBase>>>>("f");
       auto writer = RNTupleWriter::Recreate(std::move(model), "ntpl", fileGuard.GetPath());
    }
 
    auto reader = RNTupleReader::Open("ntpl", fileGuard.GetPath());
 
-   // Get the field for the `bool` member of the inner `pair`
+   // Get the field for the `a` member of the inner `TrivialTraitsBase`
    const auto field = reader->GetModel()
                          .GetDefaultEntry()
                          .begin()
                          ->GetField()
                          .GetConstSubfields()[1]
                          ->GetConstSubfields()[0]
-                         ->GetConstSubfields()[1];
+                         ->GetConstSubfields()[1]
+                         ->GetConstSubfields()[0];
 
    const auto report = ROOT::Internal::GetTypeTraceReport(*field, reader->GetDescriptor());
 
    const std::string expected{
       R"(In-memory field/type hierarchy:
-f [std::variant<double,std::vector<std::pair<float,bool>>>] (id: 0)
-  _1 [std::vector<std::pair<float,bool>>] (id: 2)
-    _0 [std::pair<float,bool>] (id: 3)
-      _1 [bool] (id: 5)
+f [std::variant<double,std::vector<std::pair<float,TrivialTraitsBase>>>] (id: 0)
+  _1 [std::vector<std::pair<float,TrivialTraitsBase>>] (id: 2)
+    _0 [std::pair<float,TrivialTraitsBase>] (id: 3)
+      _1 [TrivialTraitsBase, type version: 5, type checksum: 2623577133] (id: 5)
+        a [std::int32_t] (id: 6)
 On-disk field/type hierarchy:
-f [std::variant<double,std::vector<std::pair<float,bool>>>] (id: 0)
-  _1 [std::vector<std::pair<float,bool>>] (id: 2)
-    _0 [std::pair<float,bool>] (id: 3)
-      _1 [bool] (id: 5)
+f [std::variant<double,std::vector<std::pair<float,TrivialTraitsBase>>>] (id: 0)
+  _1 [std::vector<std::pair<float,TrivialTraitsBase>>] (id: 2)
+    _0 [std::pair<float,TrivialTraitsBase>] (id: 3)
+      _1 [TrivialTraitsBase, type version: 5, type checksum: 2623577133] (id: 5)
+        a [std::int32_t] (id: 6)
 )"};
 
    EXPECT_EQ(expected, report);