GNU bug report logs - #28156
Emacs quietly munges symlink contents

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Message #59 received at 28156 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: p.stephani2 <at> gmail.com, michael.albinus <at> gmx.de, 28156 <at> debbugs.gnu.org
Subject: Re: bug#28156: Emacs quietly munges symlink contents
Date: Mon, 21 Aug 2017 17:25:37 +0300

> Cc: michael.albinus <at> gmx.de, p.stephani2 <at> gmail.com, 28156 <at> debbugs.gnu.org
> From: Paul Eggert <eggert <at> cs.ucla.edu>
> Date: Mon, 21 Aug 2017 01:34:20 -0700
> 
> The proposed change to file-symlink-p doesn't affect support for file name 
> quoting in its argument string. All it affects is the returned string. There is 
> no need for it to quote the returned string

What if readlink returns a name such as "/ssh:foo <at> bar:/quux"?  A
symlink cannot have a remote file name as its target, can it?  So
quoting it sounds like a good way to avoid triggering a slow and
erroneous connection to some possibly non-existent host.  If we don't
quote, the caller might be in for a surprise.

> just as there is no need for read-file-name to quote the string that
> it returns.

read-file-name gets the string from the user, so it's an entirely
different context.  In that context, it's user's responsibility to
quote the file name if needed.

> Neither function is documented to quote its return value, and
> neither should do so.

Documentation in Emacs was never 110% accurate, so reading it as a
kind of formal requirements is not a good idea, IME.  This behavior is
in file-symlink-p since more than 17 years ago, so it's a de-facto
standard by now; if we decide it is what we want, we could document it
and move on.

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