[ntuple] Ensure type name given by RField<T> is renormalized

To avoid inconsistencies between the full type name of a custom class reported
by the RNTuple IO and the type name reported by ROOT meta. The commit adds a
unittest. Previously, the test would fail with exceptions such as:

```
321: unknown file: Failure
321: C++ exception with description "type mismatch for field f2: DataVector<std::int32_t,std::vector<CustomStruct>> vs. DataVector<int,vector<CustomStruct> >
321: At:
321:   void ROOT::Experimental::REntry::EnsureMatchingType(RFieldToken) const [with T = DataVector<int, std::vector<CustomStruct> >]
321: " thrown in the test body.
```

Co-authored-by: Jonas Hahnfeld <[email protected]>

Author: vepadulano

tree/ntuple/v7/inc/ROOT/RField.hxx

@@ -18,6 +18,7 @@
 
 #include <ROOT/RError.hxx>
 #include <ROOT/RFieldBase.hxx>
+#include <ROOT/RFieldUtils.hxx>
 #include <ROOT/RNTupleSerialize.hxx>
 #include <ROOT/RNTupleUtil.hxx>
 #include <ROOT/RSpan.hxx>
@@ -290,7 +291,7 @@ public:
 template <typename T, typename = void>
 class RField final : public RClassField {
 public:
-   static std::string TypeName() { return ROOT::Internal::GetDemangledTypeName(typeid(T)); }
+   static std::string TypeName() { return ROOT::Internal::GetRenormalizedDemangledTypeName(typeid(T)); }
    RField(std::string_view name) : RClassField(name, TypeName())
    {
       static_assert(std::is_class_v<T>, "no I/O support for this basic C++ type");

tree/ntuple/v7/inc/ROOT/RField/RFieldProxiedCollection.hxx

@@ -265,7 +265,7 @@ struct IsCollectionProxy : HasCollectionProxyMemberType<T> {
 template <typename T>
 class RField<T, typename std::enable_if<IsCollectionProxy<T>::value>::type> final : public RProxiedCollectionField {
 public:
-   static std::string TypeName() { return ROOT::Internal::GetDemangledTypeName(typeid(T)); }
+   static std::string TypeName() { return ROOT::Internal::GetRenormalizedDemangledTypeName(typeid(T)); }
    RField(std::string_view name) : RProxiedCollectionField(name, TypeName())
    {
       static_assert(std::is_class<T>::value, "collection proxy unsupported for fundamental types");

tree/ntuple/v7/inc/ROOT/RFieldUtils.hxx

@@ -10,6 +10,7 @@
 
 #include <string>
 #include <string_view>
+#include <typeinfo>
 #include <tuple>
 #include <vector>
 
@@ -26,6 +27,10 @@ std::string GetCanonicalTypePrefix(const std::string &typeName);
 /// Given a type name normalized by ROOT meta, renormalize it for RNTuple. E.g., insert std::prefix.
 std::string GetRenormalizedTypeName(const std::string &metaNormalizedName);
 
+/// Given a type info ask ROOT meta to demangle it, then renormalize the resulting type name for RNTuple. Useful to
+/// ensure that e.g. fundamental types are normalized to the type used by RNTuple (e.g. int -> std::int32_t).
+std::string GetRenormalizedDemangledTypeName(const std::type_info &ti);
+
 /// Applies all RNTuple type normalization rules except typedef resolution.
 std::string GetNormalizedUnresolvedTypeName(const std::string &origName);
 

tree/ntuple/v7/src/RFieldUtils.cxx

@@ -463,3 +463,8 @@ std::vector<std::string> ROOT::Internal::TokenizeTypeList(std::string_view templ
    result.push_back(std::string(typeBegin, typeCursor - typeBegin));
    return result;
 }
+
+std::string ROOT::Internal::GetRenormalizedDemangledTypeName(const std::type_info &ti)
+{
+   return ROOT::Internal::GetRenormalizedTypeName(ROOT::Internal::GetDemangledTypeName(ti));
+}

tree/ntuple/v7/test/CustomStructLinkDef.h

@@ -28,6 +28,7 @@
 #pragma link C++ class DataVector < int, double> + ;
 #pragma link C++ class DataVector < int, float> + ;
 #pragma link C++ class DataVector < bool, std::vector < unsigned int>> + ;
+#pragma link C++ class DataVector < StructUsingCollectionProxy < int>, double> + ;
 #pragma link C++ class DataVector < int, double> ::Inner + ;
 #pragma link C++ class DataVector < int, double> ::Inner + ;
 #pragma link C++ class DataVector < int, float> ::Inner + ;

tree/ntuple/v7/test/ntuple_type_name.cxx

@@ -70,6 +70,7 @@ TEST(RNTuple, TClassDefaultTemplateParameter)
       model->AddField(RFieldBase::Create("f4", "struct DataVector<bool,vector<unsigned>>").Unwrap());
       model->AddField(RFieldBase::Create("f5", "DataVector<Double32_t>").Unwrap());
       model->AddField(RFieldBase::Create("f6", "DataVector<int, double>").Unwrap());
+      model->MakeField<DataVector<StructUsingCollectionProxy<int>>>("f7");
       auto writer = RNTupleWriter::Recreate(std::move(model), "ntpl", fileGuard.GetPath());
    }
 
@@ -99,6 +100,11 @@ TEST(RNTuple, TClassDefaultTemplateParameter)
    auto v1 = reader->GetView<DataVector<int>>("f1");
    auto v3 = reader->GetView<DataVector<int>>("f3");
    EXPECT_THROW(reader->GetView<DataVector<int>>("f2"), ROOT::RException);
+
+   // Ensure the typed API does not throw an exception
+   auto f1 = reader->GetModel().GetDefaultEntry().GetPtr<DataVector<int>>("f1");
+   auto f4 = reader->GetModel().GetDefaultEntry().GetPtr<DataVector<bool, std::vector<unsigned int>>>("f4");
+   auto f7 = reader->GetModel().GetDefaultEntry().GetPtr<DataVector<StructUsingCollectionProxy<int>>>("f7");
 }
 
 TEST(RNTuple, TemplateArgIntegerNormalization)