[ntuple] prevent accidental treatment of unsupported stdlib collections

Author: jblomer

tree/ntuple/src/RFieldMeta.cxx

@@ -745,6 +745,20 @@ ROOT::RProxiedCollectionField::RProxiedCollectionField(std::string_view fieldNam
 {
    if (!classp->GetCollectionProxy())
       throw RException(R__FAIL(std::string(GetTypeName()) + " has no associated collection proxy"));
+   if (classp->Property() & kIsDefinedInStd) {
+      static const std::vector<std::string> supportedStdTypes = {
+         "std::set<", "std::unordered_set<", "std::multiset<", "std::unordered_multiset<",
+         "std::map<", "std::unordered_map<", "std::multimap<", "std::unordered_multimap<"};
+      bool isSupported = false;
+      for (const auto &tn : supportedStdTypes) {
+         if (GetTypeName().rfind(tn, 0) == 0) {
+            isSupported = true;
+            break;
+         }
+      }
+      if (!isSupported)
+         throw RException(R__FAIL(std::string(GetTypeName()) + " is not supported"));
+   }
 
    fProxy.reset(classp->GetCollectionProxy()->Generate());
    fProperties = fProxy->GetProperties();

tree/ntuple/test/ntuple_types.cxx

@@ -2056,6 +2056,9 @@ TEST(RNTuple, TClassStlDerived)
 
 TEST(RNTuple, TVirtualCollectionProxy)
 {
+   // Unsupported stdlib collections should throw
+   EXPECT_THROW(ROOT::RFieldBase::Create("l", "std::list<int>").Unwrap(), ROOT::RException);
+
    SimpleCollectionProxy<StructUsingCollectionProxy<char>> proxyC;
    // Exposing as a non-vector forces iteration over collection elements in `ReadGlobalImpl()`
    SimpleCollectionProxy<StructUsingCollectionProxy<float>, ROOT::kSTLdeque> proxyF;