[tree] Respect TChain's entryList when GetMinimum/Maximum

tree/tree/src/TChain.cxx

@@ -30,6 +30,7 @@ the trees in the chain.
 #include <iostream>
 #include <cfloat>
 #include <string>
+#include <map>
 
 #include "TBranch.h"
 #include "TBrowser.h"
@@ -66,6 +67,26 @@ the trees in the chain.
 
 ClassImp(TChain);
 
+/**
+ * @brief Helper function getting a map between treeNumber (key) defined in an entryList, and the position of the latter
+ * in the collection (value). Only those entry lists that are active (treeNumber != -1) are used to fill the map.
+ * @param elist the TChain's TEntryList
+ * @return map of int to int
+ */
+std::map<Int_t, Int_t> GetEntryListMap(const TEntryList *elist)
+{
+   const auto *elists = elist->GetLists();
+   const auto ne = elists->GetEntries();
+   std::map<Int_t, Int_t> map_elists;
+   for (Int_t e = 0; e < ne; ++e) {
+      auto el = static_cast<TEntryList *>(elists->At(e));
+      if (el && el->GetTreeNumber() >= 0) {
+         map_elists[el->GetTreeNumber()] = e;
+      }
+   }
+   return map_elists;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// Default constructor.
 
@@ -1169,12 +1190,30 @@ TObjArray* TChain::GetListOfLeaves()
 Double_t TChain::GetMaximum(const char* columname)
 {
    Double_t theMax = -DBL_MAX;
-   for (Int_t file = 0; file < fNtrees; file++) {
-      Long64_t first = fTreeOffset[file];
-      LoadTree(first);
-      Double_t curmax = fTree->GetMaximum(columname);
-      if (curmax > theMax) {
-         theMax = curmax;
+   auto elist = GetEntryList();
+   if (!elist || !elist->GetLists()) {
+      for (Int_t file = 0; file < fNtrees; file++) {
+         Long64_t first = fTreeOffset[file];
+         LoadTree(first);
+         Double_t curmax = fTree->GetMaximum(columname);
+         if (curmax > theMax) {
+            theMax = curmax;
+         }
+      }
+   } else {
+      auto map_elists = GetEntryListMap(elist);
+      for (Int_t file = 0; file < fNtrees; file++) {
+         Long64_t first = fTreeOffset[file];
+         LoadTree(first);
+         const auto prev = fTree->GetEntryList();
+         if (map_elists.find(file) != map_elists.end()) {
+            fTree->SetEntryList(static_cast<TEntryList *>(elist->GetLists()->At(map_elists[file])));
+         }
+         Double_t curmax = fTree->GetMaximum(columname);
+         fTree->SetEntryList(prev);
+         if (curmax > theMax) {
+            theMax = curmax;
+         }
       }
    }
    return theMax;
@@ -1186,12 +1225,30 @@ Double_t TChain::GetMaximum(const char* columname)
 Double_t TChain::GetMinimum(const char* columname)
 {
    Double_t theMin = DBL_MAX;
-   for (Int_t file = 0; file < fNtrees; file++) {
-      Long64_t first = fTreeOffset[file];
-      LoadTree(first);
-      Double_t curmin = fTree->GetMinimum(columname);
-      if (curmin < theMin) {
-         theMin = curmin;
+   auto elist = GetEntryList();
+   if (!elist || !elist->GetLists()) {
+      for (Int_t file = 0; file < fNtrees; file++) {
+         Long64_t first = fTreeOffset[file];
+         LoadTree(first);
+         Double_t curmin = fTree->GetMinimum(columname);
+         if (curmin < theMin) {
+            theMin = curmin;
+         }
+      }
+   } else {
+      auto map_elists = GetEntryListMap(elist);
+      for (Int_t file = 0; file < fNtrees; file++) {
+         Long64_t first = fTreeOffset[file];
+         LoadTree(first);
+         const auto prev = fTree->GetEntryList();
+         if (map_elists.find(file) != map_elists.end()) {
+            fTree->SetEntryList(static_cast<TEntryList *>(elist->GetLists()->At(map_elists[file])));
+         }
+         Double_t curmin = fTree->GetMinimum(columname);
+         fTree->SetEntryList(prev);
+         if (curmin < theMin) {
+            theMin = curmin;
+         }
       }
    }
    return theMin;

tree/tree/test/TChainRegressions.cxx

@@ -2,7 +2,9 @@
 #include <TFile.h>
 #include <TSystem.h>
 #include <TTree.h>
-
+#include <TEntryList.h>
+#include <TDirectory.h>
+
 #include "gtest/gtest.h"
 
 class TTreeCache;
@@ -30,3 +32,48 @@ TEST(TChain, GetReadCacheBug)
 
    gSystem->Unlink(filename);
 }
+
+// ROOT-7097, ROOT-8505
+TEST(TChain, GetMinMaxEntryList)
+{
+   std::unique_ptr<TFile> file1(TFile::Open("t1_7067.root", "RECREATE"));
+   TTree t1("t", "");
+   int value;
+   t1.Branch("value", &value);
+   value = 0;
+   t1.Fill();
+   value = 1;
+   t1.Fill();
+   value = 2;
+   t1.Fill();
+   value = 3;
+   t1.Fill();
+   file1->Write();
+   file1->Close();
+
+   std::unique_ptr<TFile> file2(TFile::Open("t2_7067.root", "RECREATE"));
+   TTree t2("t", "");
+   // int value;
+   t2.Branch("value", &value);
+   value = 10;
+   t2.Fill();
+   value = 11;
+   t2.Fill();
+   value = 12;
+   t2.Fill();
+   value = 13;
+   t2.Fill();
+   file2->Write();
+   file2->Close();
+
+   TChain ch("t");
+   ch.AddFile("t1_7067.root");
+   ch.AddFile("t2_7067.root");
+   EXPECT_FLOAT_EQ(ch.GetMinimum("value"), 0.);
+   EXPECT_FLOAT_EQ(ch.GetMaximum("value"), 13.);
+   ch.Draw(">>myList", "value<11 && value >1", "entrylist");
+   TEntryList *myList = static_cast<TEntryList *>(gDirectory->Get("myList"));
+   ch.SetEntryList(myList);
+   EXPECT_FLOAT_EQ(ch.GetMinimum("value"), 2.);
+   EXPECT_FLOAT_EQ(ch.GetMaximum("value"), 10.);
+}