TProtoClass: do not complaint innards of transients.

Do not complain about missing information about data members that directly or indirectly within
a transient members of the top level class in GetRealData.

This solves the underlying problem from root-project#15733

core/meta/inc/TProtoClass.h

@@ -56,7 +56,7 @@ class TProtoClass: public TNamed {
       TProtoRealData() : fOffset(0), fDMIndex(-1), fLevel(0), fClassIndex(-1), fStatusFlag(0) {}
       TProtoRealData(const TRealData *rd);
       virtual ~TProtoRealData();
-      TRealData *CreateRealData(TClass *currentClass, TClass *parent, TRealData * parentData, int prevLevel) const;
+      TRealData *CreateRealData(TClass *currentClass, TClass *parent, TRealData * parentData, int prevLevel, bool quiet) const;
 
       Bool_t TestFlag(UInt_t f) const { return (Bool_t) ((fStatusFlag & f) != 0); }
       void SetFlag(UInt_t f, Bool_t on = kTRUE) {
@@ -91,7 +91,7 @@ class TProtoClass: public TNamed {
    // compute index of data member in the list
    static Int_t DataMemberIndex(TClass * cl, const char * name);
    // find data member  given an index
-   static TDataMember * FindDataMember(TClass * cl,  Int_t index);
+   static TDataMember * FindDataMember(TClass * cl,  Int_t index, bool quiet);
 
 public:
    TProtoClass():

core/meta/src/TClass.cxx

@@ -775,7 +775,7 @@ void TBuildRealData::Inspect(TClass* cl, const char* pname, const char* mname, c
       return;
    }
 
-   Bool_t isTransientMember = kFALSE;
+   Bool_t isTransientMember = isTransient;
 
    if (!dm->IsPersistent()) {
       // For the DataModelEvolution we need access to the transient member.

core/meta/src/TProtoClass.cxx

@@ -378,7 +378,7 @@ Bool_t TProtoClass::FillTClass(TClass* cl) {
          //TProtoRealData* prd = (TProtoRealData*)element;
          // pass a previous real data only if depth
 
-         if (TRealData* rd = element.CreateRealData(currentRDClass, cl,prevRealData, prevLevel)) {
+         if (TRealData* rd = element.CreateRealData(currentRDClass, cl,prevRealData, prevLevel, element.TestFlag(TProtoRealData::kIsTransient))) {
             if (first) {
                //LM: need to do here because somehow fRealData is destroyed when calling TClass::GetListOfDataMembers()
                if (cl->fRealData) {
@@ -465,11 +465,11 @@ TProtoClass::TProtoRealData::~TProtoRealData()
 /// find data member from protoclass
 
 TRealData* TProtoClass::TProtoRealData::CreateRealData(TClass* dmClass,
-                                                       TClass* parent, TRealData *prevData, int prevLevel) const
+                                                       TClass* parent, TRealData *prevData, int prevLevel, bool quiet) const
 {
 
    //TDataMember* dm = (TDataMember*)dmClass->GetListOfDataMembers()->FindObject(fName);
-   TDataMember* dm = TProtoClass::FindDataMember(dmClass, fDMIndex);
+   TDataMember* dm = TProtoClass::FindDataMember(dmClass, fDMIndex, quiet);
 
    if (!dm && dmClass->GetState()!=TClass::kForwardDeclared && !dmClass->fIsSyntheticPair) {
       ::Error("CreateRealData",
@@ -558,7 +558,7 @@ Int_t TProtoClass::DataMemberIndex(TClass * cl, const char * name)
 }
 ////////////////////////////////////////////////////////////////////////////////
 
-TDataMember * TProtoClass::FindDataMember(TClass * cl, Int_t index)
+TDataMember * TProtoClass::FindDataMember(TClass * cl, Int_t index, bool quiet)
 {
    TList * dmList = cl->GetListOfDataMembers(false);
 
@@ -572,7 +572,7 @@ TDataMember * TProtoClass::FindDataMember(TClass * cl, Int_t index)
          return dm;
       i++;
    }
-   if (cl->GetState()!=TClass::kForwardDeclared && !cl->fIsSyntheticPair)
+   if (cl->GetState()!=TClass::kForwardDeclared && !cl->fIsSyntheticPair && !quiet)
       ::Error("TProtoClass::FindDataMember","data member with index %d is not found in class %s",index,cl->GetName());
    return nullptr;
 }