Code unloading fails assert: "Can not revert previous transactions" #9187
Description
From https://root-forum.cern.ch/t/segmentation-violation-when-re-compiling-cpp-file-after-running/47373
// minimal.cpp
# include <TRandom3.h>
# include <TH1D.h>
# include <TFile.h>
# include <TCanvas.h>
# include <TStyle.h>
# include <Riostream.h>
# include <iostream>
void particles_decay(int N0, double delta_t, double alpha, int seed = 1) {
double t=0.;
double T = 300.;
int N_survived = N0;
int N_decayed;
int N_steps = (int)(T/delta_t);
int step = 0;
double r;
TRandom3 *gRandom = new TRandom3();
gRandom -> SetSeed(seed);
TFile file("particles_decay.root", "recreate");
TCanvas* f = new TCanvas("f");
//creo oggetto TH1D per disegnare la funzione di decadimento
TH1D* N_vs_t = new TH1D("N_vs_t", "Number of particles in time", N_steps, 0, T);
while((t < T) && (N_survived > 0)) {
N_vs_t -> SetBinContent(step, N_survived);
//simulo decadimento radioattivo sulle particelle sopravvisute
N_decayed = 0;
for(int j=0; j<N_survived; j++){
r = gRandom -> Rndm();
if (r < alpha*delta_t) N_decayed++;
}
if (N_survived <= N_decayed) break;
N_survived -= N_decayed;
t += delta_t;
step++;
}
gStyle -> SetOptFit();
N_vs_t -> Fit("expo");
N_vs_t -> DrawCopy();
//Metto sul file root tutte le robe sovrapposte, nota che f punta al TCanvas aperto sopra,
//mentre il file .root con quel nome era stato anche lui creato sopra.
f -> Print("particles_decay.root");
file.Close();
}This gives
root [0] .L minimal.C
root [1] particles_decay(500, 1., 0.01)
FCN=51.0153 FROM MIGRAD STATUS=CONVERGED 40 CALLS 41 TOTAL
EDM=4.6871e-07 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 Constant 6.20101e+00 7.29140e-03 1.63914e-05 -1.00223e-01
2 Slope -1.01929e-02 6.74151e-05 1.51443e-07 4.24243e+00
Info in <TCanvas::SaveAs>: ROOT file particles_decay.root has been created
root [2] .L minimal.C
root.exe: /home/axel/build/root/master/src/interpreter/cling/lib/Interpreter/Interpreter.cpp:1513: void cling::Interpreter::unload(cling::Transaction&): Assertion `!T.getTopmostParent()->getNext() && "Can not revert previous transactions"' failed.