Function unwrap

Lib/inspect.py:663–692

Get the object wrapped by *func*. Follows the chain of :attr:`__wrapped__` attributes returning the last object in the chain. *stop* is an optional callback accepting an object in the wrapper chain as its sole argument that allows the unwrapping to be terminated early if the callbac

(func, *, stop=None)

# -------------------------------------------------------- function helpers

def unwrap(func, *, stop=None):
    """Get the object wrapped by *func*.

   Follows the chain of :attr:`__wrapped__` attributes returning the last
   object in the chain.

   *stop* is an optional callback accepting an object in the wrapper chain
   as its sole argument that allows the unwrapping to be terminated early if
   the callback returns a true value. If the callback never returns a true
   value, the last object in the chain is returned as usual. For example,
   :func:`signature` uses this to stop unwrapping if any object in the
   chain has a ``__signature__`` attribute defined.

   :exc:`ValueError` is raised if a cycle is encountered.

    """
    f = func  # remember the original func for error reporting
    # Memoise by id to tolerate non-hashable objects, but store objects to
    # ensure they aren't destroyed, which would allow their IDs to be reused.
    memo = {id(f): f}
    recursion_limit = sys.getrecursionlimit()
    while not isinstance(func, type) and hasattr(func, '__wrapped__'):
        if stop is not None and stop(func):
            break
        func = func.__wrapped__
        id_func = id(func)
        if (id_func in memo) or (len(memo) >= recursion_limit):
            raise ValueError('wrapper loop when unwrapping {!r}'.format(f))
        memo[id_func] = func
    return func

# -------------------------------------------------- source code extraction
def indentsize(line):