bug#11981: 24.1.50; url-http-parse-headers should not disable file name handlers since it breaks auth-source

[David Engster <deng@randomsample.de>]

Stefan Monnier writes:
>>> However, this workaraound assumes that everything that gets afterwards
>>> in the `let'-section does not depend on file name handlers. However,
>>> this is not the case: `url-http-handle-authentication' is called which
>>> in turn calls the auth-source package. This package however supports
>>> encrypted authinfo files which have to be automatically decrypted
>>> through `auto-encryption-mode'. This, of course, works through file name
>>> handlers.
>> Does it work, if Tramp is disabled instead?
>
> I think I'd first like to better understand bug#6717: why do we take
> a local part of a URL, let it start with / and then pass it to
> file-name-directory?  That sounds like a problem in itself.

I agree. I wonder which call to `file-name-directory' threw the error in
the original report - the most likely candidate is `url-file-directory',
which should simply be rewritten to not use `file-name-directory'.

-David