def _save_and_remove_module(name, orig_modules):
"""Helper function to save and remove a module from sys.modules
- Return value is True if the module was in sys.modules and
- False otherwise."""
+ Return True if the module was in sys.modules, False otherwise.
+ Raise ImportError if the module can't be imported."""
saved = True
try:
orig_modules[name] = sys.modules[name]
except KeyError:
+ # try to import the module and raise an error if it can't be imported
+ __import__(name)
saved = False
else:
del sys.modules[name]
def _save_and_block_module(name, orig_modules):
"""Helper function to save and block a module in sys.modules
- Return value is True if the module was in sys.modules and
- False otherwise."""
+ Return True if the module was in sys.modules, False otherwise."""
saved = True
try:
orig_modules[name] = sys.modules[name]
the sys.modules cache is restored to its original state.
Modules named in fresh are also imported anew if needed by the import.
+ If one of these modules can't be imported, None is returned.
Importing of modules named in blocked is prevented while the fresh import
takes place.
if not _save_and_block_module(blocked_name, orig_modules):
names_to_remove.append(blocked_name)
fresh_module = importlib.import_module(name)
+ except ImportError:
+ fresh_module = None
finally:
for orig_name, module in orig_modules.items():
sys.modules[orig_name] = module