bug#50946: Emacs-28: Inadequate coding in hack-elisp-shorthands

[Eli Zaretskii]

> Date: Fri, 1 Oct 2021 17:10:57 +0000
> From: Alan Mackenzie <acm@muc.de>
> 
> In emacs -Q in the emacs-28 branch, create the following two line file,
> foobar.el, and try to load it:
> 
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> (defvar foo-baz "foobar-baz")
> FOOBARELISP-SHORTHANDS: (("foo" . "foobar")))
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> 
> This will throw an error, but that isn't important.
> 
> What is important is that the symbol foobar-baz is created by the
> elisp-shorthands facility.
> 
> This shouldn't happen since:
> 1/- There is no Local Variables section.
> 2/- There is no variable elisp-shorthands in that non-existent section.
> 
> The following errors are evident in hack-elisp-shorthands:
> 1/- The code doesn't check for a correctly formatted Local Variables
>   section.
> 2/- The code, even if it did check, would only check the last 3000 bytes
>   in the file.  The section can occur anywhere in the last 3000
>   CHARACTERS.
> 3/- The code doesn't do a case-sensitive search for "elisp-shorthands".
> 4/- The code doesn't check for "elisp-shorthands" being a complete
>   symbol.
> 5/- The code doesn't even check that "elisp-shorthands" is in a comment.

Thanks.

João, could you please look into this?