[hist] Throw on streaming Experimental classes

Author: hahnjo

hist/histv7/inc/LinkDef.h

@@ -0,0 +1,2 @@
+#pragma link C++ class ROOT::Experimental::RRegularAxis-;
+#pragma link C++ class ROOT::Experimental::RVariableBinAxis-;

hist/histv7/inc/ROOT/RRegularAxis.hxx

@@ -8,6 +8,9 @@
 #include "RLinearizedIndex.hxx"
 
 #include <cstddef>
+#include <stdexcept>
+
+class TBuffer;
 
 namespace ROOT {
 namespace Experimental {
@@ -86,6 +89,9 @@ public:
       std::size_t bin = (x - fLow) * fInvBinWidth;
       return {bin, true};
    }
+
+   /// ROOT Streamer function to throw when trying to store an object of this class.
+   void Streamer(TBuffer &) { throw std::runtime_error("unable to store RRegularAxis"); }
 };
 
 } // namespace Experimental

hist/histv7/inc/ROOT/RVariableBinAxis.hxx

@@ -8,9 +8,12 @@
 #include "RLinearizedIndex.hxx"
 
 #include <cstddef>
+#include <stdexcept>
 #include <utility>
 #include <vector>
 
+class TBuffer;
+
 namespace ROOT {
 namespace Experimental {
 
@@ -84,6 +87,9 @@ public:
       std::size_t bin = fBinEdges.size() - 2;
       return {bin, true};
    }
+
+   /// ROOT Streamer function to throw when trying to store an object of this class.
+   void Streamer(TBuffer &) { throw std::runtime_error("unable to store RVariableBinAxis"); }
 };
 
 } // namespace Experimental

hist/histv7/standalone.cmake

@@ -1,3 +1,5 @@
+set(histv7_standalone TRUE)
+
 include(GNUInstallDirs)
 include(headers.cmake)
 

hist/histv7/test/CMakeLists.txt

@@ -1,2 +1,6 @@
 HIST_ADD_GTEST(hist_regular hist_regular.cxx)
 HIST_ADD_GTEST(hist_variable hist_variable.cxx)
+
+if(NOT DEFINED histv7_standalone)
+  ROOT_ADD_GTEST(hist_io hist_io.cxx LIBRARIES RIO ROOTHist)
+endif()

hist/histv7/test/hist_io.cxx

@@ -0,0 +1,36 @@
+#include "hist_test.hxx"
+
+#include <ROOT/TestSupport.hxx>
+#include <TMemFile.h>
+
+#include <stdexcept>
+
+template <typename T>
+static void ExpectThrowOnWriteObject(const T &obj)
+{
+   ROOT::TestSupport::CheckDiagsRAII diagRAII;
+   diagRAII.optionalDiag(kWarning, "TKey::TKey", "no public constructor", /*matchFullMessage=*/false);
+
+   TMemFile f("mem.root", "RECREATE");
+   EXPECT_THROW(f.WriteObject(&obj, "o"), std::runtime_error);
+}
+
+TEST(RRegularAxis, Streamer)
+{
+   static constexpr std::size_t Bins = 20;
+   const RRegularAxis axis(Bins, 0, Bins);
+   ExpectThrowOnWriteObject(axis);
+}
+
+TEST(RVariableBinAxis, Streamer)
+{
+   static constexpr std::size_t Bins = 20;
+   std::vector<double> bins;
+   for (std::size_t i = 0; i < Bins; i++) {
+      bins.push_back(i);
+   }
+   bins.push_back(Bins);
+
+   const RVariableBinAxis axis(bins);
+   ExpectThrowOnWriteObject(axis);
+}