Fix runtime error

GeneratorInterface/Core/interface/LHEWeightHelper.h

@@ -20,6 +20,9 @@ namespace gen {
   class LHEWeightHelper : public WeightHelper {
   public:
     LHEWeightHelper() : WeightHelper(){};
+
+    enum ErrorType { SWAPHEADER, HTMLSTYLE, TRAILINGSTR, UNKNOWN };
+
     void setHeaderLines(std::vector<std::string> headerLines);
     void parseWeights();
     bool isConsistent();
@@ -28,10 +31,14 @@ namespace gen {
 
   private:
     std::vector<std::string> headerLines_;
+    std::string weightgroupKet_ = "</weightgroup>";
     bool failIfInvalidXML_ = false;
     std::string parseGroupName(tinyxml2::XMLElement* el);
     void addGroup(tinyxml2::XMLElement* inner, std::string groupName, int groupIndex, int& weightIndex);
     bool parseLHE(tinyxml2::XMLDocument& xmlDoc);
+    tinyxml2::XMLError tryReplaceHtmlStyle(tinyxml2::XMLDocument& xmlDoc, std::string& fullHeader);
+    tinyxml2::XMLError tryRemoveTrailings(tinyxml2::XMLDocument& xmlDoc, std::string& fullHeader);
+    ErrorType findErrorType(std::string& fullHeader);
   };
 }  // namespace gen
 

GeneratorInterface/Core/src/LHEWeightHelper.cc

@@ -12,34 +12,36 @@ namespace gen {
   bool LHEWeightHelper::parseLHE(tinyxml2::XMLDocument& xmlDoc) {
     parsedWeights_.clear();
 
-    if (!isConsistent() && failIfInvalidXML_) {
-      throw cms::Exception("LHEWeightHelper")
-          << "XML in LHE is not consistent: Most likely, XML tags are out of order.";
-    } else if (!isConsistent()) {
-      swapHeaders();
-    }
-
     std::string fullHeader = boost::algorithm::join(headerLines_, "");
     if (debug_)
       std::cout << "Full header is \n" << fullHeader << std::endl;
     int xmlError = xmlDoc.Parse(fullHeader.c_str());
 
-    // in case of &gt; instead of <
-    if (xmlError != 0 && failIfInvalidXML_) {
-      xmlDoc.PrintError();
-      throw cms::Exception("LHEWeightHelper")
-          << "The LHE header is not valid XML! Weight information was not properly parsed.";
-    } else if (xmlError != 0 && !failIfInvalidXML_) {
-      boost::replace_all(fullHeader, "&lt;", "<");
-      boost::replace_all(fullHeader, "&gt;", ">");
-      xmlError = xmlDoc.Parse(fullHeader.c_str());
-    }
+    while (!isConsistent() || xmlError != 0) {
+      if (failIfInvalidXML_) {
+        xmlDoc.PrintError();
+        throw cms::Exception("LHEWeightHelper")
+            << "The LHE header is not valid XML! Weight information was not properly parsed.";
+      }
 
-    // error persists (how to handle error?)
-    if (xmlError != 0) {
-      std::string error = "Fatal error when parsing the LHE header. The header is not valid XML! Parsing error was ";
-      error += xmlDoc.ErrorStr();
-      throw cms::Exception("LHEWeightHelper") << error;
+      switch (findErrorType(fullHeader)) {
+        case ErrorType::SWAPHEADER:
+          swapHeaders();
+          fullHeader = boost::algorithm::join(headerLines_, "");
+          xmlError = xmlDoc.Parse(fullHeader.c_str());
+          break;
+        case ErrorType::HTMLSTYLE:
+          xmlError = tryReplaceHtmlStyle(xmlDoc, fullHeader);
+          break;
+        case ErrorType::TRAILINGSTR:
+          xmlError = tryRemoveTrailings(xmlDoc, fullHeader);
+          break;
+        case ErrorType::UNKNOWN:
+          std::string error =
+              "Fatal error when parsing the LHE header. The header is not valid XML! Parsing error was ";
+          error += xmlDoc.ErrorStr();
+          throw cms::Exception("LHEWeightHelper") << error;
+      }
     }
 
     return true;
@@ -151,4 +153,34 @@ namespace gen {
       }
     }
   }
+
+  tinyxml2::XMLError LHEWeightHelper::tryReplaceHtmlStyle(tinyxml2::XMLDocument& xmlDoc, std::string& fullHeader) {
+    // in case of &gt; instead of <
+    boost::replace_all(fullHeader, "&lt;", "<");
+    boost::replace_all(fullHeader, "&gt;", ">");
+
+    return xmlDoc.Parse(fullHeader.c_str());
+  }
+
+  tinyxml2::XMLError LHEWeightHelper::tryRemoveTrailings(tinyxml2::XMLDocument& xmlDoc, std::string& fullHeader) {
+    // delete extra strings after the last </weightgroup> (occasionally contain '<' or '>')
+    std::size_t theLastKet = fullHeader.rfind(weightgroupKet_) + weightgroupKet_.length();
+    fullHeader = fullHeader.substr(0, theLastKet);
+
+    return xmlDoc.Parse(fullHeader.c_str());
+  }
+
+  LHEWeightHelper::ErrorType LHEWeightHelper::findErrorType(std::string& fullHeader) {
+    if (!isConsistent())
+      return LHEWeightHelper::ErrorType::SWAPHEADER;
+    if (fullHeader.find("&lt;") != std::string::npos || fullHeader.find("&gt;") != std::string::npos)
+      return LHEWeightHelper::ErrorType::HTMLSTYLE;
+
+    std::string trailingCand =
+        fullHeader.substr(fullHeader.rfind(weightgroupKet_) + std::string(weightgroupKet_).length());
+    if (trailingCand.find('<') != std::string::npos || trailingCand.find('>') != std::string::npos)
+      return LHEWeightHelper::ErrorType::TRAILINGSTR;
+
+    return LHEWeightHelper::ErrorType::UNKNOWN;
+  }
 }  // namespace gen

PhysicsTools/NanoAOD/python/nanogen_cff.py

@@ -7,6 +7,7 @@
 from PhysicsTools.NanoAOD.lheInfoTable_cfi import *
 from PhysicsTools.NanoAOD.genVertex_cff import *
 from PhysicsTools.NanoAOD.common_cff import Var,CandVars
+from PhysicsTools.NanoAOD.genWeights_cff import *
 
 nanoMetadata = cms.EDProducer("UniqueStringProducer",
     strings = cms.PSet(