[PyROOT] Pythonize constructors to give ownership to current TFile

Python gives up ownership if the TTree or TH1 is attached to a TFile,
which is the owner in that case.

(cherry picked from commit 23c893d)

Author: guitargeek

bindings/pyroot/pythonizations/python/ROOT/_pythonization/_th1.py

@@ -23,6 +23,45 @@ def _imul(self, c):
     return self
 
 
+def _TH1_Constructor(self, *args, **kwargs):
+    """
+    Forward the arguments to the C++ constructor and give up ownership if the
+    TH1 is attached to a TFile, which is the owner in that case.
+    """
+    import ROOT
+
+    self._cpp_constructor(*args, **kwargs)
+    tdir = self.GetDirectory()
+    if tdir and type(tdir).__cpp_name__ == "TFile":
+        ROOT.SetOwnership(self, False)
+
+# The constructors need to be pythonized for each derived class separately:
+
+@pythonization('TH1D')
+def pythonize_th1(klass):
+    klass._cpp_constructor = klass.__init__
+    klass.__init__ = _TH1_Constructor
+
+@pythonization('TH1F')
+def pythonize_th1(klass):
+    klass._cpp_constructor = klass.__init__
+    klass.__init__ = _TH1_Constructor
+
+@pythonization('THDF')
+def pythonize_th1(klass):
+    klass._cpp_constructor = klass.__init__
+    klass.__init__ = _TH1_Constructor
+
+@pythonization('TH2F')
+def pythonize_th1(klass):
+    klass._cpp_constructor = klass.__init__
+    klass.__init__ = _TH1_Constructor
+
+@pythonization('TProfile')
+def pythonize_th1(klass):
+    klass._cpp_constructor = klass.__init__
+    klass.__init__ = _TH1_Constructor
+
 @pythonization('TH1')
 def pythonize_th1(klass):
     # Parameters:

bindings/pyroot/pythonizations/python/ROOT/_pythonization/_ttree.py

@@ -279,13 +279,27 @@ def _TTree__getattr__(self, key):
         out = cppyy.ll.cast[cast_type](out)
     return out
 
+def _TTree_Constructor(self, *args, **kwargs):
+    """
+    Forward the arguments to the C++ constructor and give up ownership if the
+    TTree is attached to a TFile, which is the owner in that case.
+    """
+    import ROOT
+
+    self._cpp_constructor(*args, **kwargs)
+    tdir = self.GetDirectory()
+    if tdir and type(tdir).__cpp_name__ == "TFile":
+        ROOT.SetOwnership(self, False)
 
 @pythonization("TTree")
 def pythonize_ttree(klass, name):
     # Parameters:
     # klass: class to be pythonized
     # name: string containing the name of the class
 
+    klass._cpp_constructor = klass.__init__
+    klass.__init__ = _TTree_Constructor
+
     # Pythonizations that are common to TTree and its subclasses.
     # To avoid duplicating the same logic in the pythonizors of
     # the subclasses, inject the pythonizations for all the target
@@ -321,3 +335,10 @@ def pythonize_tchain(klass):
     # SetBranchAddress
     klass._OriginalSetBranchAddress = klass.SetBranchAddress
     klass.SetBranchAddress = _SetBranchAddress
+
+@pythonization("TNtuple")
+def pythonize_tchain(klass):
+
+    # The constructor needs to be explicitly pythonized for derived classes.
+    klass._cpp_constructor = klass.__init__
+    klass.__init__ = _TTree_Constructor