GNU bug report logs - #54486
29.0.50; Eshell `escaped' string property can "leak" into output

Previous Next

Package: emacs;

Reported by: Jim Porter <jporterbugs <at> gmail.com>

Date: Mon, 21 Mar 2022 03:53:02 UTC

Severity: normal

Found in version 29.0.50

Done: Jim Porter <jporterbugs <at> gmail.com>

Bug is archived. No further changes may be made.

Full log


Message #22 received at 54486-done <at> debbugs.gnu.org (full text, mbox):

From: Jim Porter <jporterbugs <at> gmail.com>
To: 54486-done <at> debbugs.gnu.org
Subject: Re: 29.0.50; Eshell `escaped' string property can "leak" into output
Date: Sat, 23 Nov 2024 22:56:54 -0800
On 3/20/2022 8:52 PM, Jim Porter wrote:
> When using Eshell, it's possible to inadvertently add an `escaped' 
> string property to strings, resulting in some pretty surprising 
> behavior. Starting from "emacs -Q --eval '(eshell)'":
> 
>    ~ $ setq var (list "foo" "bar")
>    ("foo" "bar")
>    ~ $ echo $var
>    ("foo" "bar")
>    ~ $ echo $var[0]
>    foo
>    ~ $ echo $var
>    (#("foo" 0 3
>       (escaped t))
>     "bar")

In the intervening years, I've improved Eshell's parser to prevent other 
bugs, which has resulted in the 'escaped' string property no longer 
being useful.

Instead, Eshell now propertizes text that has actual syntactic meaning: 
for example a globbing character like "*" gets the 'eshell-glob-char' 
text property. By marking *syntactic* characters with a text property, 
we ensure that Eshell only ever adds properties to text literally 
written into the Eshell buffer, which avoids the issue here.

As a result of all this, we can now remove the calls that added that 
property in Eshell. I've now made this change in b4655ff99b5, so closing 
this bug.




This bug report was last modified 216 days ago.

Previous Next


GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.