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From: Eli Zaretskii <eliz@gnu.org>
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Subject: Re: Allowing symlinked dir-locals files?
Date: Mon, 16 Aug 2021 21:12:16 +0300
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To: Yuri D'Elia <wavexx@thregr.org>
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> From: Yuri D'Elia <wavexx@thregr.org>
> Date: Mon, 16 Aug 2021 20:01:20 +0200
> 
> Looking at the current files.el:4330, we explicitly check if the file is
> a regular file. And looking at the FIXME comment just above I concur
> that checking just for file-directory-p should be sufficient for proper
> behavior.
> 
> However I suspect that the rationale was to be proper as well as "safe",
> as this could be used to make emacs read/interpret another file if the
> symlink is under the control of a VCS or via a shared-filesystem.

Yes.  It could also be a symlink injected by malevolent hackers.