From 08b34d72a800bd48ea4655f17075de0ef3ca72cb Mon Sep 17 00:00:00 2001
From: Philippe Canal <pcanal@fnal.gov>
Date: Fri, 3 Mar 2023 13:23:45 -0600
Subject: [PATCH] fBits read: preserve kIsOnHeap, always set kNotDeleted.

Rather than reading from the file the value of kIsOnHeap, preserve the value that was
calculated at object creation time (i.e. in the current execution).  For example, for
an embedded object (inside an object created on the heap or stack), the bit always
need to be off (i.e. it can never be explicitly deleted)
---
 core/base/src/TObject.cxx             | 3 ++-
 io/io/src/TStreamerInfoActions.cxx    | 2 ++
 io/io/src/TStreamerInfoReadBuffer.cxx | 6 +++++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/core/base/src/TObject.cxx b/core/base/src/TObject.cxx
index 1f1d97d191fa5..a50a547f5efcd 100644
--- a/core/base/src/TObject.cxx
+++ b/core/base/src/TObject.cxx
@@ -797,8 +797,9 @@ void TObject::Streamer(TBuffer &R__b)
    if (R__b.IsReading()) {
       R__b.SkipVersion(); // Version_t R__v = R__b.ReadVersion(); if (R__v) { }
       R__b >> fUniqueID;
+      const UInt_t isonheap = fBits & kIsOnHeap; // Record how this instance was actually allocated.
       R__b >> fBits;
-      fBits |= kIsOnHeap;  // by definition de-serialized object is on heap
+      fBits |= isonheap | kNotDeleted;  // by definition de-serialized object are not yet deleted.
       if (TestBit(kIsReferenced)) {
          //if the object is referenced, we must read its old address
          //and store it in the ProcessID map in gROOT
diff --git a/io/io/src/TStreamerInfoActions.cxx b/io/io/src/TStreamerInfoActions.cxx
index 35179b4e59357..2a1df6648990d 100644
--- a/io/io/src/TStreamerInfoActions.cxx
+++ b/io/io/src/TStreamerInfoActions.cxx
@@ -227,7 +227,9 @@ namespace TStreamerInfoActions
       UInt_t *x = (UInt_t*)( ((char*)addr) + config->fOffset );
       // Idea: Implement buf.ReadBasic/Primitive to avoid the return value
       // Idea: This code really belongs inside TBuffer[File]
+      const UInt_t isonheap = *x & TObject::kIsOnHeap; // Record how this instance was actually allocated.
       buf >> *x;
+      *x |= isonheap | TObject::kNotDeleted;  // by definition de-serialized object are not yet deleted.
 
       if ((*x & kIsReferenced) != 0) {
          HandleReferencedTObject(buf,addr,config);
diff --git a/io/io/src/TStreamerInfoReadBuffer.cxx b/io/io/src/TStreamerInfoReadBuffer.cxx
index 68ce0948f4064..07c291b949bde 100644
--- a/io/io/src/TStreamerInfoReadBuffer.cxx
+++ b/io/io/src/TStreamerInfoReadBuffer.cxx
@@ -608,6 +608,7 @@ Int_t TStreamerInfo::ReadBufferConv(TBuffer &b, const T &arr,  const TCompInfo *
          DOLOOP {
             UInt_t u;
             b >> u;
+            u |= kNotDeleted;  // by definition de-serialized object are not yet deleted.
             if ((u & kIsReferenced) != 0) {
                UShort_t pidf;
                b >> pidf;
@@ -1018,7 +1019,10 @@ Int_t TStreamerInfo::ReadBuffer(TBuffer &b, const T &arr,
          // special case for TObject::fBits in case of a referenced object
          case TStreamerInfo::kBits: {
             DOLOOP {
-               UInt_t *x=(UInt_t*)(arr[k]+ioffset); b >> *x;
+               UInt_t *x=(UInt_t*)(arr[k]+ioffset);
+               const UInt_t isonheap = *x & TObject::kIsOnHeap; // Record how this instance was actually allocated.
+               b >> *x;
+               *x |= isonheap | TObject::kNotDeleted;  // by definition de-serialized object are not yet deleted.
                if ((*x & kIsReferenced) != 0) {
                   UShort_t pidf;
                   b >> pidf;