Build error in core/src/PythonProc.cc with ROOT 6.36

[plexoos]

505 12.84 /esi/ratpac-two/src/core/src/PythonProc.cc:64:25: error: no member named 'Eval' in 'TPython'                 
506 12.84    64 |   int result = TPython::Eval(cmd.c_str());                                                           
507 12.84       |                ~~~~~~~~~^                                                                            
508 12.98 1 warning generated.                                                                                         

The TPython::Eval() function that was deprecated in ROOT 6.34 and scheduled for removal in ROOT 6.36 is removed.

https://root.cern/doc/v636/release-notes.html

[JamesJieranShen]

Thanks for the report! I looked into this quickly, the correct solution is to replace the DSEvent logic with the following (might need additional testing)

  std::string cmd = "_anyresult = " + fPyProcName + ".dsevent(ds)";
  std::any result;
  bool python_ok = TPython::Exec(cmd.c_str(), &result);
  if (python_ok == -1) Log::Die("Python exception.");
  return std::any_cast<Processor::Result>(result);

@plexoos -- Hopefully putting this patch in will circumvent the compile error.

But unfortunately this signature to TPython::Eval with the extra result flag is not supported in ROOT V6.28, which is the nominal version installed using ratpac-setup...

For @rat-pac/maintainers -- a discussion should be made how we want to support legacy behaviors like this. Is ratpac2 still the super forward-looking codebase where we only support the newest interface of ROOT/G4, or should we start putting in macros for controlling code behavior for different versions of ROOT? Support for old interfaces like this tend to get poorly tested and poorly supported very quickly -- there are still checks in RATPAC2 on if we are running Geant4 v9 or v10, and I'm willing to bet the codebase is not compatible with Geant4 v9 whatsoever at this point. On the other hand , the root version we are running is only 3 years old!

[Adztarrant]

Hi James,

I also have ran in to this problem in the past. Often found the rat setup scripts tempermental and so just load it in myself.

I have tried your new code snipet and it still does not complie as it still contains TPython::Eval experision. I'm using root 6.36.04. To get it to complie I had to change it to Exec. I haven't writen or used any python classes as a RAT Processor so this might not be the soultion but this at least allowed me to complie and have yet to see any ineresting result of breaks.

[JamesJieranShen]

Hi James,

I also have ran in to this problem in the past. Often found the rat setup scripts tempermental and so just load it in myself.

I have tried your new code snipet and it still does not complie as it still contains TPython::Eval experision. I'm using root 6.36.04. To get it to complie I had to change it to Exec. I haven't writen or used any python classes as a RAT Processor so this might not be the soultion but this at least allowed me to complie and have yet to see any ineresting result of breaks.

My apologies, that's a typo -- it should have been Exec.