[RF] Do not stream RooAbsArg eocache to avoid memory leak when reading back workspaces

[will-cern]

This memory leak is demonstrated with the following ROOT macro:

{
  {
    RooExpensiveObjectCache::instance(); // force the standard instance construction (otherwise created in factory method call)
    cout << "make ws" << endl;
    RooWorkspace w("combined", "combined");
    cout << "factory method:" << endl;
    w.factory("RooGaussian::gaus(x[-5,5],mean[0,-5,5],sigma[1,0.1,3])");
    w.writeToFile("/tmp/test.root");
    cout << "reading back" << endl;
    {
      TFile f("/tmp/test.root");
      RooWorkspace *w2 = f.Get<RooWorkspace>("combined");
      std::cout << "deleting w2" << endl;
      delete w2;
    }
    std::cout << "deleting w" << endl;
  }
}

along with a modification to RooExpensiveObjectCache to printout when an instance is being constructed or destructed. Before this fix the above then prints out (I annotated the output a bit):

Processing test.C...
Created 0x12cb8cc68 <--- this is the static instance
make ws
Created 0x7ffee2baaab0 <--- the workspace's cache
factory method:
reading back
Created 0x7fcbc7b39008 <--- the read-back workspace's cache
Created 0x7fcbd45a0b70 <--- memory leaking cache
deleting w2
Destroyed 0x7fcbc7b39008
deleting w
Destroyed 0x7ffee2baaab0
root [1] .q
Destroyed 0x12cb8cc68

After the fix caches are created and destroyed as expected:

Processing test.C...
Created 0x1290a5c68
make ws
Created 0x7ffee623eab0
factory method:
reading back
Created 0x7f9bd8437408
deleting w2
Destroyed 0x7f9bd8437408
deleting w
Destroyed 0x7ffee623eab0
root [1] .q
Destroyed 0x1290a5c68

[phsft-bot]

Can one of the admins verify this patch?

[guitargeek]

@phsft-bot build

[phsft-bot]

Starting build on ROOT-debian10-i386/soversion, ROOT-performance-centos8-multicore/cxx17, ROOT-ubuntu18.04/nortcxxmod, ROOT-ubuntu2004/python3, mac12/noimt, mac11/cxx14, windows10/cxx14
How to customize builds

[phsft-bot]

Build failed on mac12/noimt.
Running on macphsft17.dyndns.cern.ch:/Users/sftnight/build/jenkins/workspace/root-pullrequests-build
See console output.

Warnings:

• [2023-01-13T12:35:18.342Z] /Users/sftnight/build/jenkins/workspace/root-pullrequests-build/root/core/base/src/TDirectory.cxx:1245:7: warning: 'sprintf' is deprecated: This function is provided for compatibility reasons only. Due to security concerns inherent in the design of sprintf(3), it is highly recommended that you use snprintf(3) instead. [-Wdeprecated-declarations]

Failing tests:

• projectroot.roottest.cling.const.roottest_cling_const_run2
• projectroot.roottest.cling.dict.roottest_cling_dict_rundefaultargs_compiled
• projectroot.roottest.cling.dict.roottest_cling_dict_exectemplatetemplateTest
• projectroot.roottest.cling.dict.roottest_cling_dict_runalgebra
• projectroot.roottest.cling.functionTemplate.roottest_cling_functionTemplate_testcint
• projectroot.roottest.cling.other.roottest_cling_other_runsprintfselect
• projectroot.roottest.cling.parsing.roottest_cling_parsing_ptrconst
• projectroot.roottest.cling.printf.roottest_cling_printf_star
• projectroot.roottest.cling.template.roottest_cling_template_defaultTemplateParam
• projectroot.roottest.cling.typedef.roottest_cling_typedef_assertFuncArray

And 63 more

[guitargeek]

LGTM, thank you very much for this important fix!