[PyROOT] Drop support for from ROOT import *

README/ReleaseNotes/v632/index.md

@@ -44,6 +44,7 @@ The following people have contributed to this new version:
 - Some redundant **RooDataSet** constructors are deprecated and will be removed in ROOT 6.34.
   Please use the RooDataSet constructors that take RooFit command arguments instead
 - ROOT does not longer support Python 2. The minimum required Python version to build ROOT is 3.8.
+- Support for wildcard imports like `from ROOT import *` is dropped from PyROOT
 
 ## Core Libraries
 

bindings/pyroot/pythonizations/python/ROOT/__init__.py

@@ -55,6 +55,26 @@
 
 _is_ipython = hasattr(builtins, "__IPYTHON__")
 
+
+class _PoisonedDunderAll:
+    """
+    Dummy class used to trigger an ImportError on wildcard imports if the
+    `__all__` attribute of a module is an instance of this class.
+    """
+
+    def __getitem__(self, _):
+        import textwrap
+
+        message = """
+        Wildcard import e.g. `from module import *` is bad practice, so it is disallowed in ROOT. Please import explicitly.
+        """
+        raise ImportError(textwrap.dedent(message))
+
+
+# Prevent `from ROOT import *` by setting the __all__ attribute to something
+# that will raise an ImportError on item retrieval.
+__all__ = _PoisonedDunderAll()
+
 # Configure ROOT facade module
 import sys
 from ._facade import ROOTFacade
@@ -127,7 +147,12 @@ def is_package(self, fullname: str) -> bool:
         return _lookup_root_module(fullname) is not None
 
     def create_module(self, spec: ModuleSpec):
-        return _lookup_root_module(spec.name)
+        out = _lookup_root_module(spec.name)
+        # Prevent wildcard import for the submodule by setting the __all__
+        # attribute to something that will raise an ImportError on item
+        # retrieval.
+        out.__all__ = _PoisonedDunderAll()
+        return out
 
     def exec_module(self, module):
         pass

bindings/pyroot/pythonizations/python/ROOT/_facade.py

@@ -82,9 +82,8 @@ def __init__(self, module, is_ipython):
         types.ModuleType.__init__(self, module.__name__)
 
         self.module = module
-        # Importing all will be customised later
-        self.module.__all__ = []
 
+        self.__all__ = module.__all__
         self.__name__ = module.__name__
         self.__file__ = module.__file__
         self.__cached__ = module.__cached__
@@ -145,22 +144,6 @@ def AddressOf(self, obj):
         # Create a buffer (LowLevelView) from address
         return cppyy.ll.cast[out_type](addr)
 
-    def _handle_import_all(self):
-        # Called if "from ROOT import *" is executed in the app.
-        # Customises lookup in Python's main module to also
-        # check in C++'s global namespace
-
-        # Get caller module (jump over the facade frames)
-        num_frame = 2
-        frame = sys._getframe(num_frame).f_globals["__name__"]
-        while frame == "ROOT._facade":
-            num_frame += 1
-            frame = sys._getframe(num_frame).f_globals["__name__"]
-        caller = sys.modules[frame]
-
-        # Install the hook
-        cppyy_backend._set_cpp_lazy_lookup(caller.__dict__)
-
     def _fallback_getattr(self, name):
         # Try:
         # - in the global namespace
@@ -170,13 +153,8 @@ def _fallback_getattr(self, name):
         # The first two attempts allow to lookup
         # e.g. ROOT.ROOT.Math as ROOT.Math
 
-        if name == "__all__":
-            self._handle_import_all()
-            # Make the attributes of the facade be injected in the
-            # caller module
-            raise AttributeError()
         # Note that hasattr caches the lookup for getattr
-        elif hasattr(gbl_namespace, name):
+        if hasattr(gbl_namespace, name):
             return getattr(gbl_namespace, name)
         elif hasattr(gbl_namespace.ROOT, name):
             return getattr(gbl_namespace.ROOT, name)