Re: How to reject visiting a file

[Óscar Fuentes]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>>> Is there a way to error-out when Emacs tries to visit certain file
>>>> before the file is loaded? I'll like to use a hook that receives the
>>>> file name and be able to throw an error from there that aborts the
>>>> operation.
>>> You could define a file-handler for these files.
>> Yes, that looks like a solution.
>> For the record, the relevant info is in the Elisp manual:
>>     Making Certain File Names “Magic”
>
> I think that's going to be pretty heavyweight.

I hope not. The function will inspect the file name (possibly the
primitive too) and either throw an error or delegate to
file-name-non-special.

> A simpler approach is something like
>
>     (defun sm-prevent-visiting-files (filename &rest _)
>       (if (string-match "nasty-file-name" filename)
>           (error "Bad! Bad file name! Bad!")))
>     (advice-add 'find-file-noselect :before #'sm-prevent-visiting-files)

That was my first idea, but it was discarded because I'm not sure about
its coverage. I don't know the method a given package can use to
visit/load/read a file.