From fb3a8b190829389c83848f3df22ae5e793d692f0 Mon Sep 17 00:00:00 2001
From: Brian <bbockelm@cse.unl.edu>
Date: Tue, 3 Sep 2013 15:37:39 +0200
Subject: [PATCH] Keep a copy of the original exception info and append it to
 the fallback file-open failure message.

---
 IOPool/Input/src/RootInputFileSequence.cc | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/IOPool/Input/src/RootInputFileSequence.cc b/IOPool/Input/src/RootInputFileSequence.cc
index 3d88d84459884..53d35f14225fd 100644
--- a/IOPool/Input/src/RootInputFileSequence.cc
+++ b/IOPool/Input/src/RootInputFileSequence.cc
@@ -199,6 +199,7 @@ namespace edm {
     bool hasFallbackUrl = !fallbackName.empty() && fallbackName != fileIter_->fileName();
 
     boost::shared_ptr<InputFile> filePtr;
+    std::list<std::string> originalInfo;
     try {
       std::unique_ptr<InputSource::FileOpenSentry>
         sentry(inputType_ == InputType::Primary ? new InputSource::FileOpenSentry(input_, lfn_, usedFallback_) : 0);
@@ -211,6 +212,7 @@ namespace edm {
           out << e.explainSelf();
           std::string pfn(gSystem->ExpandPathName(fallbackName.c_str()));
           InputFile::reportFallbackAttempt(pfn, fileIter_->logicalFileName(), out.str());
+          originalInfo = e.additionalInfo();
         } else {
           InputFile::reportSkippedFile(fileIter_->fileName(), fileIter_->logicalFileName());
           Exception ex(errors::FileOpenError, "", e);
@@ -237,7 +239,15 @@ namespace edm {
           std::ostringstream out;
           out << "Input file " << fileIter_->fileName() << " could not be opened.\n";
           out << "Fallback Input file " << fallbackName << " also could not be opened.";
-          ex.addAdditionalInfo(out.str());
+          if (originalInfo.size()) {
+            out << std::endl << "Original exception info is above; fallback exception info is below.";
+            ex.addAdditionalInfo(out.str());
+            for (auto const & s : originalInfo) {
+              ex.addAdditionalInfo(s);
+            }
+          } else {
+            ex.addAdditionalInfo(out.str());
+          }
           throw ex;
         }
       }