Function _exec

Lib/importlib/_bootstrap.py:818–839

Execute the spec's specified module in an existing module's namespace.

(spec, module)

# Used by importlib.reload().
def _exec(spec, module):
    """Execute the spec's specified module in an existing module's namespace."""
    name = spec.name
    with _ModuleLockManager(name):
        if sys.modules.get(name) is not module:
            msg = f'module {name!r} not in sys.modules'
            raise ImportError(msg, name=name)
        try:
            if spec.loader is None:
                if spec.submodule_search_locations is None:
                    raise ImportError('missing loader', name=spec.name)
                # Namespace package.
                _init_module_attrs(spec, module, override=True)
            else:
                _init_module_attrs(spec, module, override=True)
                spec.loader.exec_module(module)
        finally:
            # Update the order of insertion into sys.modules for module
            # clean-up at shutdown.
            module = sys.modules.pop(spec.name)
            sys.modules[spec.name] = module
    return module

def _load_unlocked(spec):
    # A helper for direct use by the import system.