Using decorators of optional dependency

Question

Lets say I have the following code:

try:
    import bar
except ImportError:
    bar = None

@bar.SomeProvidedDecorator
def foo():
    pass

where bar is an optional dependency. The code above will fail, if bar isn't imported. Is there a recommended way of dealing with this problem?

I came up with:

try:
    import bar
except ImportError:
    bar = None

def foo():
    pass

if bar is not None:
    foo = bar.SomeProvidedDecorator(foo)

but I'm wondering if there are better ways of handling this (i.e. is there a way to keep the decorator syntax) ?

Answer 1

Provide an identity decorator in case of bar unavailability:

try:
    import bar
except ImportError:
    class bar:
        SomeProvidedDecorator = lambda f: f