[io] TDirectoryFile: propagate returnExistingDirectory to sub-calls

Author: silverweed

io/io/src/TDirectoryFile.cxx

@@ -1287,7 +1287,7 @@ TDirectory *TDirectoryFile::mkdir(const char *name, const char *title, Bool_t re
          tmpdir = (TDirectoryFile*)mkdir(workname.Data(),title);
          if (!tmpdir) return nullptr;
       }
-      return tmpdir->mkdir(slash + 1);
+      return tmpdir->mkdir(slash + 1, "", returnExistingDirectory);
    }
 
    TDirectory::TContext ctxt(this);

io/io/test/TFileTests.cxx

@@ -5,6 +5,8 @@
 
 #include "gtest/gtest.h"
 
+#include <ROOT/TestSupport.hxx>
+
 #include "TFile.h"
 #include "TMemFile.h"
 #include "TDirectory.h"
@@ -280,6 +282,21 @@ TEST(TDirectoryFile, SeekParent)
    EXPECT_EQ(dir11->GetSeekParent(), 239);
 }
 
+TEST(TDirectoryFile, RecursiveMkdir)
+{
+   TMemFile f("mkdirtest.root", "RECREATE");
+   auto dir1 = f.mkdir("a/b/c");
+   EXPECT_NE(dir1, nullptr);
+   {
+      ROOT::TestSupport::CheckDiagsRAII diags;
+      diags.requiredDiag(kError, "TDirectoryFile::mkdir","An object with name c exists already");
+      auto dir2 = f.mkdir("a/b/c", "", /* returnExisting = */ false);
+      EXPECT_EQ(dir2, nullptr);
+   }
+   auto dir3 = f.mkdir("a/b/c", "", /* returnExisting = */ true);
+   EXPECT_EQ(dir3, dir1);
+}
+
 // https://its.cern.ch/jira/browse/ROOT-10581
 TEST(TFile, PersistTObjectStdArray)
 {