From fe42bc0a7187f8172692a4b6ca93cd60388973bb Mon Sep 17 00:00:00 2001
From: Philippe Canal <pcanal@fnal.gov>
Date: Thu, 13 Oct 2016 12:34:04 -0700
Subject: [PATCH] Avoid access gROOT after its teardown in destructors (Fix
 ROOT-8395)

---
 graf2d/graf/src/TCutG.cxx          | 3 ++-
 math/fumili/src/TFumili.cxx        | 3 ++-
 montecarlo/eg/src/TDatabasePDG.cxx | 3 ++-
 tree/tree/src/TChain.cxx           | 8 +++++---
 4 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/graf2d/graf/src/TCutG.cxx b/graf2d/graf/src/TCutG.cxx
index 49c71b29220b6..ce71aee05fd15 100644
--- a/graf2d/graf/src/TCutG.cxx
+++ b/graf2d/graf/src/TCutG.cxx
@@ -242,7 +242,8 @@ TCutG::~TCutG()
 {
    delete fObjectX;
    delete fObjectY;
-   gROOT->GetListOfSpecials()->Remove(this);
+   if ( gROOT && !gROOT->TestBit( TObject::kInvalidObject ) )
+      gROOT->GetListOfSpecials()->Remove(this);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/math/fumili/src/TFumili.cxx b/math/fumili/src/TFumili.cxx
index fdaa4168040bf..edc3492058dc9 100644
--- a/math/fumili/src/TFumili.cxx
+++ b/math/fumili/src/TFumili.cxx
@@ -211,7 +211,8 @@ void TFumili::BuildArrays(){
 
 TFumili::~TFumili() {
    DeleteArrays();
-   gROOT->GetListOfSpecials()->Remove(this);
+   if (gROOT && !gROOT->TestBit(TObject::kInvalidObject))
+      gROOT->GetListOfSpecials()->Remove(this);
    if (gFumili == this) gFumili = 0;
 }
 
diff --git a/montecarlo/eg/src/TDatabasePDG.cxx b/montecarlo/eg/src/TDatabasePDG.cxx
index 66426747caabb..5f7f220964e62 100644
--- a/montecarlo/eg/src/TDatabasePDG.cxx
+++ b/montecarlo/eg/src/TDatabasePDG.cxx
@@ -91,7 +91,8 @@ TDatabasePDG::~TDatabasePDG()
       fListOfClasses->Delete();
       delete fListOfClasses;
    }
-   gROOT->GetListOfSpecials()->Remove(this);
+   if (gROOT && !gROOT->TestBit(TObject::kInvalidObject))
+      gROOT->GetListOfSpecials()->Remove(this);
    auto fgInstance = GetInstancePtr();
    *fgInstance = nullptr;
 }
diff --git a/tree/tree/src/TChain.cxx b/tree/tree/src/TChain.cxx
index 5e9e016eb6aef..4d1d22ef750ae 100644
--- a/tree/tree/src/TChain.cxx
+++ b/tree/tree/src/TChain.cxx
@@ -173,7 +173,9 @@ TChain::TChain(const char* name, const char* title)
 
 TChain::~TChain()
 {
-   gROOT->GetListOfCleanups()->Remove(this);
+   bool rootAlive = gROOT && !gROOT->TestBit(TObject::kInvalidObject);
+
+   if (rootAlive) gROOT->GetListOfCleanups()->Remove(this);
 
    SafeDelete(fProofChain);
    fStatus->Delete();
@@ -196,10 +198,10 @@ TChain::~TChain()
    delete[] fTreeOffset;
    fTreeOffset = 0;
 
-   gROOT->GetListOfSpecials()->Remove(this);
+   if (rootAlive) gROOT->GetListOfSpecials()->Remove(this);
 
    // Remove from the global list
-   gROOT->GetListOfDataSets()->Remove(this);
+   if (rootAlive) gROOT->GetListOfDataSets()->Remove(this);
 
    // This is the same as fFile, don't delete it a second time.
    fDirectory = 0;