bug#18535: tramp alters `vc-handled-backends'

[Stefan Monnier]

>> The current code uses a `let' binding, which uses the same mechanism as
>> unwind-protect, so I don't think that's the source of a the problem.
> Is this common behavior in Lisps?  I could not find any reference to
> this in the Elisp manual.

The Elisp manual's description is not in terms of implementation, so it
doesn't say that, but it does document that behavior.  E.g.:

   When that local binding is no longer in effect, the
   previously shadowed value (or lack of one) comes back.

>> The `delq' look dangerous on the other hand.  Shouldn't these be
>> `remq' instead?
> yes, this seems to solve the problem.

Thanks, installed,


        Stefan