[io] test for renaming with unversioned classes

roottest/root/io/evolution/versions/execROOT14491.cxx

@@ -0,0 +1,71 @@
+// See https://github.com/root-project/root/issues/14491#issuecomment-1917587621
+#ifndef SIMPLEREAD
+#define SIMPLEREAD
+
+#include <vector>
+#include <iostream>
+#include "Rtypes.h"
+
+template <typename T>
+struct Wrapper
+{
+   bool present = true;
+   T obj;
+};
+
+struct MatchedCSCSegment
+{
+   float someValue = 0.0;
+
+   MatchedCSCSegment(float in = 0.0) : someValue{in} {}
+
+   // The simple update failed if the class version was not set.
+   // ClassDef(MatchedCSCSegment, 5);
+};
+
+struct CSCSegment
+{
+   float someValue;
+
+   operator MatchedCSCSegment()
+   {
+      return MatchedCSCSegment{someValue};
+   }
+
+   std::vector<MatchedCSCSegment> theDuplicateSegments;
+
+   // ClassDef(CSCSegment, 4);
+};
+
+#ifdef __ROOTCLING__
+#pragma link C++ class MatchedCSCSegment+;
+#pragma link C++ class CSCSegment+;
+#pragma link C++ class Wrapper<std::vector<CSCSegment>>+;
+#pragma read sourceClass="CSCSegment" targetClass="MatchedCSCSegment"
+#endif
+
+#endif
+
+#include "TFile.h"
+#include "TTree.h"
+
+void test(TTree *t, const char *bname)
+{
+   std::string formula = bname;
+   formula += ".obj.theDuplicateSegments@.size()";
+   t->Scan(formula.c_str());
+}
+
+int execROOT14491()
+{
+   auto file = TFile::Open("oldfile14491.root", "READ");
+   auto t = file->Get<TTree>("t");
+   t->LoadTree(0);
+   // gDebug = 7;
+   test(t, "seg_split");
+   // gDebug = 0;
+   test(t, "seg_unsplit");
+   file->Close();
+   delete file;
+   return 0;
+}

roottest/root/io/evolution/versions/execROOT14491.ref

@@ -0,0 +1,13 @@
+
+Processing execROOT14491.cxx+...
+***********************************
+*    Row   * Instance * seg_split *
+***********************************
+*        0 *        0 *         0 *
+***********************************
+***********************************
+*    Row   * Instance * seg_unspl *
+***********************************
+*        0 *        0 *         1 *
+***********************************
+(int) 0