From 2156115db5b95646f922dd3fea3eaa0aefee2a2c Mon Sep 17 00:00:00 2001
From: scott snyder <sss@karma>
Date: Fri, 13 Nov 2020 22:18:11 -0500
Subject: [PATCH] xAODRootAccess: Don't crash opening a schema-evolved file.
Don't crash opening a file that uses some kinds of automatic schema evolution.
If the type of a member changes from one class to another
(for example, from std::vector<double> to std::vector<float>),
then GetExpectedType will give us the on-disk class.
To get the class we use in memory, we need to use GetCurrentClass.
---
Control/xAODRootAccess/Root/TAuxStore.cxx | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/Control/xAODRootAccess/Root/TAuxStore.cxx b/Control/xAODRootAccess/Root/TAuxStore.cxx
index c28951eec91..87e8a6115a7 100644
--- a/Control/xAODRootAccess/Root/TAuxStore.cxx
+++ b/Control/xAODRootAccess/Root/TAuxStore.cxx
@@ -13,6 +13,9 @@
#include <TClass.h>
#include <TROOT.h>
#include <TVirtualCollectionProxy.h>
+#include <TBranchElement.h>
+#include <TStreamerInfo.h>
+#include <TStreamerElement.h>
// EDM include(s):
#include "AthContainers/AuxTypeRegistry.h"
@@ -1469,6 +1472,19 @@ namespace xAOD {
br->GetName() );
}
+ // Check for schema evolution:
+ // If a branch has automatic schema evolution from one class to another,
+ // then what we get from GetExpectedType will be the on-disk class.
+ // What we have in memory is given by GetCurrentClass.
+ if (expectedClass) {
+ if (TBranchElement* bre = dynamic_cast<TBranchElement*> (br)) {
+ TClass* newClass = bre->GetCurrentClass();
+ if (newClass && newClass != expectedClass) {
+ expectedClass = newClass;
+ }
+ }
+ }
+
// If this is a primitive variable, and we're still not sure whether this
// is a store for an object or a container, the answer is given...
if( ( ! expectedClass ) &&
--
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